Final report project (THESIS ) LAST YEAR {MECHANICAL 4TH YEAR}

CFD ANALYSIS OF PARALLEL FLOW HEAT EXCHANGER
ME DEPARTMENT, SRMGPC, LUCKNOW Page 1
CHAPTER-1
1.1. INTRODUCTION
Heat exchanger is a process equipment designed for the effective transfer of heat energy between
two fluids. For the heat transfer to occur two fluids must be at different temperatures and they
must come thermal contact. Heat exchange involve convection in each fluid and conduction
through the separating wall. Heat can flow only from hotter to cooler fluids, as per the second law
of thermodynamics.
A heat exchanger is a device used to transfer heat between two or more fluids. Heat exchangers
are used in both cooling and heating processes. The fluids may be separated by a solid wall to
prevent mixing or they may be in direct contact. They are widely used in space
heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical
plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of
a heat exchanger is found in an internal combustion engine in which a circulating fluid known
as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant
and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger
that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often
air or a liquid coolant.
Heat exchangers are widely used in industry both for cooling and heating large scale
industrial processes. The type and size of heat exchanger used can be tailored to suit a process
depending on the type of fluid, its phase, temperature, density, viscosity, pressures, chemical
composition and various other thermodynamic properties.
In many industrial processes there is waste of energy or a heat stream that is being exhausted,
heat exchangers can be used to recover this heat and put it to use by heating a different stream in
the process. This practice saves a lot of money in industry, as the heat supplied to other streams
from the heat exchangers would otherwise come from an external source that is more expensive
and more harmful to the environment.
Heat exchangers use containment vessels to heat or cool one fluid by transferring heat between it
and another fluid. Users of heat exchangers include chemical, petrochemical, oil & gas, power
generation, refrigeration, pharmaceuticals, HVAC, food & beverage processing and pulp & paper
industries.
A plate heat exchanger is a specialized design well suited to transferring heat between medium
and low pressure fluids. Plate heat exchangers contain thin plates joined together with a small
space between them allowing fluid to flow between a larger surface area. They are highly
efficient and more compact in design than other forms of heat exchangers.

Shell and tube heat exchangers are well suited for high pressure applications. They consist of a
shell with a bundle of tubes inside it transferring heat from within and around the bundle.
Air cooled heat exchangers are pressure vessels which cool a circulating fluid within finned tubes
by forcing ambient air over the exterior of the tubes.
1.2 DEFINITION
In a typical Heat exchanger, heat is Shared/Exchanged between two fluids.
But A Boiler generates heat through chemical reaction of the fuel, and exchanges the heat with
the water to produce steam or heated water depending on the application.
If we take the above definition for comparison, A Boiler can't be termed as a Heat
Exchanger because the process of Heat generation through chemical reaction isn't there in a Heat
Exchanger.
1.3 HISTORY OF HEAT EXCHANGERS
The first known heat exchangers for homes were simply rocks placed in a fire. The rocks would
store the heat from the fire and could then be moved inside of a hut or small tent to warm the
interior without fear of burning it down. The heat that was being lost from the fire was captured
by the heat transfer surface, the rock, and used to heat the inside of the residence. This same
method of thought led to the development of the hot water bottle.
The first “central” home heating was invented by the Romans, though there is evidence that the
Indians may have been using this “hypocaust” technology up to two millennia earlier. The
premise involved a basement room located under the main floor. The floor was made with cement
sandwiched between layers of tiles on the top and bottom. Space was left for hot air and smoke
from fires in the basement to travel through the flooring so heat could radiate up into the room.
The same technology was used to heat the public baths.
1.3.1 INTERNATIONALUSE
Koreans used a similar technology, called Ondol heating, for the last thousand years. With the
Ondol heaters, hot air and smoke would be channeled from the wood fires used for cooking into
pipes run under the floors.

It would be another 1700 years or so beyond the hypocaust before the next major advancement
took place in heat exchanger technology. This time, a Frenchman, Jean Simon Bonnemain, used a
hot water system to help with the incubation of chicken eggs. In the eighteen hundreds, the
Marquis de Chabannes used a similar technology to heat a sort of greenhouse for growing grapes.
Then the Price brothers introduced hot water and steam heating to England and patented a system
for home heating in 1829. Over the next half century, hot water and steam heat exchangers would
revolutionize the world.
1.3.2 BRAZED EXCHANGERS
Brazed heat exchangers are the smallest and most compact of heat exchangers used today. They
were first introduced in the 1920s. When the exchanger’s plates are brazed together, they can be
used under high pressure and can contain caustic or toxic materials safely. Because of their ability
to be created in small sizes, but with efficient surface area usage, the plate heat exchangers are the
most common heat exchangers used in refrigeration and HVAC systems.
1.3.3 CURRENTUSES
Today, heat exchangers have been developed in forms so small they can fit in the palm of your
hand, and so large they require cranes and jumbo aircraft to move them. For example, the
largest plate and frame heat exchanger in the world stands 81 feet tall and weighs over 450 tons
(900,000 pounds). Heat exchangers are used in everything, from our laptops and refrigerators to
petrochemical refineries and food, drink, and pharmaceutical manufacturing. The capture and re-
allocation of once-lost heat energy saves billions of dollars in expenses every year and makes
processes requiring high pressure feasible.
Heat exchangers now come in many varieties, each meeting a specific need in the market. From
the shell and tube to the plate and shell, the plate and fin to the adiabatic wheel, and the pillow
plate to regenerative models, there are almost as many heat exchanger designs as there are varying
needs. Heat exchangers can also be categorized by the number of fluids run through the exchanger,
the types of materials used (gas to liquid, liquid to liquid, liquid to phase change), or even by the
flow.
1.3.4 FUTURE
Heat exchangers have come a long way from the boiling pot and brick oven, but where will they
take us in the years to come? Soon, entire cities will have access to fully renewable power.
Consider the massive solar fields in Morocco, the Mohave Desert, and Vojens, Denmark. These
three solar fields alone produce enough energy to support several million people. With the

advances in underground storage technology being perfected at Vojens, the sun’s power may
soon be harnessed and stored without batteries, within the earth.
While some energy sources come from outside (the sun), others come from within the earth itself.
Heat exchangers are taking advantage of geothermal heat sources to power entire hotels in New
Zealand, and entire communities, such as Fort Polk, Louisiana.
If you are interested in joining the millions who are already saving money, reducing carbon
emissions, and increasing production efficiency, then the addition or upgrade of heat
exchanger technology may be right for you.
TABLE1.0 TYPES OF HEAT EXCHANGERS
1
Air cooled heat
exchanger
Rectangular tube bundles mounted
on frame, with air used as the
cooling medium
2 Double pipe
Pipe within a pipe; inner pipe may be
finned or plain
3
Extended
Surface
Externally finned tube
4 Brazed plate fin
Series of plates separated by
corrugated fins
5 Spiral wound
Spirally wound tube coils within a
shell
6
Barometric
condenser
Direct contact of water and vapor
7 Bayonet tube
Tube elements consists of an inner
and tube
8 Scraped surface
Pipe within a pipe, with rotating
blades scraping the inside wall of the
inner pipe
9
Falling film
cooler
Vertical units using a the film of
water in tubes
10
Cascade
coolers
Cooling water flows over series of
tubes
11 Shell and tube
Bundle of tubes encased in a cylinder
shell

1.4.1 Air cooledheat exchanger
Water shortage and increasing costs, together with more recent concerns about water pollution
and cooling tower plumes, have greatly reduced industry's use of water cooled heat exchangers.
Consequently, when further heat integration within the plant is not possible, it is now usual to
reject heat directly to the atmosphere, and a large proportion of the process cooling in refineries
and chemical plants takes place in Air Cooled Heat Exchangers (AC-HEs).
There is also increasing use of Air Cooled Condensers for power stations. The basic principles are
the same but these are specialized items and are normally configured as an A-frame or "roof
type". These condensers may be very large-the condensers for a 4000 MW power station in South
Africa have over 2300 tube bundles, 288 fans each 9.1 m in diameter and a total plot area 500 m
X 70 m.
AC-HEs for process plants are normally just called Aircoolers, but should not be confused with
devices for cooling air (best described as Air Chillers).
The design of an AC-HE is more complex than for a Shell and Tube Heat Exchanger, as there are
many more components and variables.
The structure of an AC-HE is painted or galvanized, depending on customer specification.
However, the costs are roughly the same if a multiple coat paint system is specified. Often the
painted units are more expensive. There seems to be a trend toward more galvanized structures
because they require virtually no maintenance. Painted structures require touch-up after
installation and they often rust anyway.
Air-cooled heat exchangers are used extensively throughout the oil and gas industry, from
upstream production to refineries and petrochemical plants, under high pressure and high
temperature conditions, as well as corrosive fluids and environments.

FIG 1.1 : TYPICAL INDUCED DRAUGHT AIR COOLED HEAT EXCHANGER
1.4.2 DOUBLE PIPE HEAT EXCHANGER
A double pipe heat exchanger (also sometimes referred to as a 'pipe-in-pipe' exchanger) is a type
of heat exchanger comprising a 'tube in tube' structure. As the name suggests, it consists of two
pipes, one within the other. One fluid flows through the inner pipe (analogous to the tube-side in a
shell and tube type exchanger) whilst the other flows through the outer pipe, which surrounds the
inner pipe (analogous to the shell-side in a shell and tube exchanger).
A cross-section of a double pipe exchanger would look something like this:

FIG 1.2: DOUBLE PIPE HEAT EXCHANGER PARALLEL FLOW
They often have a U-tube structure to accommodate thermal expansion of the tubes without
necessitating expansion joints.
1.4.3 EXTENDEDSURFACE HEAT TRANSFER
FIG 1.3: EXTENDED SURFACE HEAT EXCHANGER

Extended surfaces have fins attached to the primary surface on one side of a two-fluid or a
multifluid heat exchanger. Fins can be of a variety of geometry—plain, wavy or interrupted—and
can be attached to the inside, outside or to both sides of circular, flat or oval tubes, or parting
sheets. Pins are primarily used to increase the surface area (when the heat transfer coefficient on
that fluid side is relatively low) and consequently to increase the total rate of heat transfer. In
addition, enhanced fin geometries also increase the heat transfer coefficient compared to that for a
plain fin. Fins may also be used on the high heat transfer coefficient fluid side in a heat exchanger
primarily for structural strength (for example, for high pressure water flow through a flat tube) or
to provide a thorough mixing of a highly-viscous liquid (such as for laminar oil flow in a flat or a
round tube).
1.4.4 BRAZED PLATE FIN HEAT EXCHANGERS
Brazed plate heat exchangers are one of the most efficient ways to transfer heat. They are designed
to provide unparalleled performance with the lowest life-cycle cost. Choosing brazed technology
for your next heating or cooling project will bring many benefits, including savings in space,
energy, and maintenance.
FIG 1.4: BRAZED PLATE HEAT EXCHANGERS

1.4.5 SPIRAL WOUND HEAT EXCHANGER
FIG 1.5: SPIRAL WOUND HEAT EXCHANGER
The coil wound heat exchanger shown in Figure 1 consists of carefully spaced helices of small-
diameter tubes of equal length through which the high-pressure streams flow. They are wrapped
around a core cylinder, called the mandrel, in a number of layers and enclosed in an insulated
cylindrical jacket, called the shell. The length of the shell is typically less than one-sixth of that of
the tubes. The tubes are therefore generally wound with multiple starts. The low-pressure stream
flows across the wound tubes in the space between the inner cylinder (mandrel) and the outer
jacket (shell).
1.4.6 BAROMETRICCONDENSER
A surface condenser is a commonly used term for a water-cooled shell and tube heat
exchanger installed on the exhaust steam from a steam turbine in thermal power stations.
These condensers are heat exchangers which convert steam from its gaseous to its liquid state at a
pressure below atmospheric pressure. Where cooling water is in short supply, an air-cooled
condenser is often used. An air-cooled condenser is however, significantly more expensive and
cannot achieve as low a steam turbine exhaust pressure (and temperature) as a water-cooled surface
condenser.
Surface condensers are also used in applications and industries other than the condensing of steam
turbine exhaust in power plants.

National and international test codes are used to standardize the procedures and definitions used in
testing large condensers. In the U.S., ASME publishes several performance test codes on
condensers and heat exchangers. These include ASME PTC 12.2-2010, Steam Surface
Condensers,and PTC 30.1-2007, Air cooled Steam Condensers.
The Barometric Condenser is employed in a variety of industries as an economical means of
removing air, exhaust steam, and other vapors from vacuum equipment. ... A principal feature of
the Barometric Condenser is that injection water may be discharged through a tail pipe by
gravity, without requiring a pump.
FIG 1.6: BAROMETRIC CONDENSER
1.4.7 BAYONET TUBE HEAT EXCHANGER

A heat exchanger according to the present invention is provided with bayonet tubes in its shell.
One end of each of bayonet tube outer ducts is secured to and open at a tube sheet fixed at one end
of the shell. One end of each of bayonet tube inner ducts is secured to and opened to a hot gas
separation chamber. The other ends of inner and outer duct communicate with each other. A hot
gas separation chamber is provided inside the tube side pressure drum which is attached to and in
contact with the tube sheet. Such construction of a heat exchanger according to the invention as
this prevents thermal stress from arising, rendering the design of economical and reliable heat
exchangers possible.
A bayonet tube heat exchanger is typically a pair of concentric tubes, the outer of which has a
closed end that creates a clearance pass between the inner and annulus tube. This paper evaluates
the impact of key parameters and operating conditions on the performance of a bayonet tube by
utilizing computational fluid dynamic approach and Taguchi statistical method.
A validated two-dimensional model, that considers conservation of mass, momentum and energy,
was employed together with an L25 orthogonal array (OA) of Taguchi matrix of five factors and
five level designs to determine the optimum combination of parameters as well as their
interactions. The result indicates that pipe total length and length of clearance area play an
important role in determining the bayonet tube performance in term of pressure drop and heat
transfer. The optimum combination of design and operating parameters were obtained with the
objective of maximizing the efficiency and performance of the bayonet tube.

FIG 1.7: BAYONET TUBE HEAT EXCHANGER
1.4.8 SCRAPED SURFACE HEAT EXCHANGER
Figure 1.8 SCRAPED SURFACE HEAT EXCHANGER

The dynamic scraped surface heat exchanger (DSSHE) was designed to face some problems
found in other types of heat exchangers. They increase heat transfer by: removing
the fouling layers, increasing turbulence in case of high viscosity flow, and avoiding the generation
of ice and other process by-products. DSSHEs incorporate an internal mechanism which
periodically removes the product from the heat transfer wall.
1.4.9 FALLING FILM COOLER
Falling film evaporator is an industrial device to concentrate solutions, especially with heat
sensitive components. The evaporator is a special type of heat exchanger.
In general evaporation takes place inside vertical tubes, but there are also applications where the
process fluid evaporates on the outside of horizontal or vertical tubes. In all cases, the process fluid
to be evaporated flows downwards by gravity as a continuous film.
The fluid distributor has to be designed carefully in order to maintain an even liquid distribution for
all tubes along which the solution falls. A typical distributor is shown in Fig. 2; these distributors
are usually called ferrules due to their concentric shape. In the majority of applications the heating
medium is placed on the outside of the tubes. High heat transfer coefficients are required in order
to achieve equally balanced heat transfer resistances. Therefore, condensing steam is commonly
used as a heating medium.

FIG: 1.9 FALLING FILM WATER COOLER
The fluid distributor has to be designed carefully in order to maintain an even liquid distribution for
all tubes along which the solution falls. A typical distributor is shown in Fig. 2; these distributors
are usually called ferrules due to their concentric shape. In the majority of applications the heating
medium is placed on the outside of the tubes. High heat transfer coefficients are required in order
to achieve equally balanced heat transfer resistances. Therefore, condensing steam is commonly
used as a heating medium.
For internally evaporating fluids, separation between the liquid phase (the solution) and the
gaseous phase takes place inside the tubes. In order to maintain conservation of mass as this
process proceeds, the downward vapor velocity increases, increasing the shear force acting on the
liquid film and therefore also the velocity of the solution. The result can be a high film velocity of a
progressively thinner film resulting in increasingly turbulent flow. The combination of these effects
allows very high heat transfer coefficients.
The heat transfer coefficient on the evaporating side of the tube is mostly determined by the
hydrodynamic flow conditions of the film. For low mass flows or high viscosities the film flow can
be laminar, in which case heat transfer is controlled purely by conduction through the film.
Therefore in this condition the heat transfer coefficient decreases with increased mass flow. With
increased mass flow the film becomes wavy laminar and then turbulent. Under turbulent conditions
the heat transfer coefficient increases with increased flow.
Evaporation takes place at very low mean temperature differences between heating medium and
process stream, typically between 3 - 6K, therefore these devices are ideal for heat recovery in
multi stage processes. A further advantage of the falling film evaporator is the very short residence
time of the liquid and the absence of superheating of the same. Not considering the vapour
separator, the residence time inside the tubes is measured in seconds, making it ideal for heat-
sensitive products such as milk, fruit juice, pharmaceuticals, and many others.
Falling film evaporators are also characterised by very low pressure drops; therefore, they are often
used in deep vacuum applications.
1.4.10 SHELLAND TUBE TYPE HEAT EXCHANGER
A shell and tube heat exchanger is a class of heat exchanger designs. It is the most common type
of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-
pressure applications. As its name implies, this type of heat exchanger consists of a shell (a
large pressure vessel) with a bundle of tubes inside it. One fluid runs through the tubes, and another
fluid flows over the tubes (through the shell) to transfer heat between the two fluids. The set of
tubes is called a tube bundle, and may be composed of several types of tubes: plain, longitudinally
finned, etc.

One of fluids is carried through a bundle of tubes enclosed by a shell. The other fluid is forced
through the shell and flows over the outside surface of tubes.
FIG 1.10:SHELL AND TUBE TYPE HEAT EXCHANGER
Two fluids, of different starting temperatures, flow through the heat exchanger. One flows through
the tubes (the tube side) and the other flows outside the tubes but inside the shell (the shell side).
Heat is transferred from one fluid to the other through the tube walls, either from tube side to shell
side or vice versa. The fluids can be either liquids or gases on either the shell or the tube side. In
order to transfer heat efficiently, a large heat transfer area should be used, leading to the use of
many tubes. In this way, waste heat can be put to use. This is an efficient way to conserve energy.
1.5 CONSTRUCTION OF SHELL AND TUBE TYPE HEAT EXCHANGER
Although there exists a wide range of designs and materials, some components are common in all
shell and tube designs.
Shell and tube heat exchangers represent the most widely used vehicle for heat transfer in process
applications. They frequently are selected for duties such as:
 Process liquid or gas cooling.
 Process or refrigerant vapor or steam condensing.
 Process liquid, steam or refrigerant evaporation.
 Process heat removal and preheating of feedwater.
 Thermal energy conservation efforts and heat recovery.

FIG 1.11: CONSTRUCTION OF SHELL AND TUBE EXCHANGER
Although there exists a wide range of designs and materials, some components are common to all.
In all shell and tube heat exchangers, the tubes are mechanically attached to tube sheets, which are
contained inside a shell with ports for inlet and outlet fluid or gas. They are designed to prevent the
liquid flowing inside the tubes from mixing with the fluid outside the tubes. Tube sheets can be
fixed to the shell or allowed to expand and contract with thermal stresses. In the latter design, an
expansion bellows is used or one tube sheet is allowed to float inside the shell. The nonfixed tube
sheet approach allows the entire tube bundle assembly to be pulled from the shell to allow cleaning
of the shell circuit.
1.5.1 FLUID STREAM ALLOCATION
There are a number of practical guidelines that, if followed, can lead to the optimum design of a
given heat exchanger. Remembering that the heat exchanger's primary responsibility is to perform
its thermal duty with the lowest cost yet provide in-service reliability, the selection of fluid stream
allocations should be of primary concern to the designer. When designing, keep the following
points in mind:-
 The higher pressure fluid normally flows through the tube side. With their small diameter and
nominal wall thicknesses, the tubes are better able to accept high pressures, and this approach
avoids having to design more expensive, larger diameter components for high pressure. If it is
necessary to put the higher pressure fluid stream in the shell, it should be placed in a small
diameter, long shell.

All other items being equal, place corrosive fluids in the tubes. It is much less expensive to use the
special alloys designed to resist corrosion for the tubes than for the shell. Other tube-side
components can be clad with corrosion-resistant materials or epoxy coated.
 Flow higher fouling fluids through the tubes.Tubes are easier to clean using common mechanical
methods than the shell.
 Many possible designs and configurations - affecting tube pitch, baffle use and spacing, and
multiple nozzles, to name a few - can be used when laying out the shell circuit. Because of this, it
is best to place fluids requiring low pressure drops in the shell circuit.
 The fluid with the lower heat transfer coeffi cient normally goes in the shell circuit. With this
setup, low-fin tubing, which will increase available surface area, can be used to offset the low heat
transfer rate.
1.5.2 TUBES
Heat exchangers with shell diameters of 10 to more than 100" typically are manufactured to
the standards set forth by the Tubular Exchangers Manufacturers Association. Generally,
the 0.625 to 1.5" tubing used in TEMA-sized exchangers is made from low carbon steel,
copper, Admiralty, copper-nickel, stainless steel, Hastalloy, Inconel, titanium or other
materials.
Tubes are either drawn and seamless, or welded. High quality electroresistance welded tubes
exhibit good grain structure at the weld. Extruded tube with low fins and interior rifling is specified
for certain applications. Surface enhancements are used to increase the available metal surface or
aid in fluid turbulence, thereby increasing the effective heat transfer rate. Finned tubing is
recommended when the shell-side fluid has a substantially lower heat transfer coefficient than the
tube-side fluid. Finned tubing is not finned in its landing areas, where it contacts the tube sheets.
Also, the outside diameter of the finned portions of this tube design is slightly smaller than the
unfinned areas. These features allow the tubes to be slid easily through the baffles and tube
supports during assembly while still minimizing fluid bypass.
U-tube designs are specified when the thermal difference between the fluids and flows would result
in excessive thermal expansion of the tubes. U-tube bundles do not have as much tube surface as
straight tube bundles due to the bending radius, and the curved ends cannot be easily cleaned.
Additionally, interior tubes are difficult to replace and often requiring the removal of outer layers
or simply plugging the tubes. To ease manufacturing and service, it is common to use a removable
tube bundle design when specifying U-tubes.
1.5.3 TUBE SHEETS

Tube sheets usually are made from a round, flat piece of metal. Holes are drilled for the tube ends
in a precise location and pattern relative to one another. Tube sheets are manufactured from the
same range of materials as tubes. Tubes are attached to the tube sheet by pneumatic or hydraulic
pressure, or by roller expansion. If needed, tube holes can be drilled and reamed, or they can be
machined with one or more grooves. This greatly increases tube joint strength (figure 1.12).
The tube sheetisin contact withbothfluids,soitmusthave corrosionresistance allowancesand
metallurgical andelectrochemical propertiesappropriate forthe fluidsandvelocities.Low carbonsteel
tube sheetscaninclude alayerof a higheralloymetal bondedtothe surface toprovide more effective
corrosionresistance withoutthe expense of usingthe solidalloy.
The tube hole pattern, or "pitch," varies the distance from one tube to the other as well as the angle
of the tubes relative to each other and to the direction of flow. This allows the fluid velocities and
pressure drop to be manipulated to provide the maximum amount of turbulence and tube surface
contact for effective heat transfer.
Where the tube and tube sheet materials are joinable weldable metals, the tube joint can be further
strengthened by applying a seal weld or strength weld to the joint. In a strength weld, a tube is
slightly recessed inside the tube hole or slightly extended beyond the tube sheet. The weld adds
metal to the resulting lip. A seal weld is specified to help prevent the shell and tube liquids from
intermixing. In this treatment, the tube is flush with the tube sheet surface. The weld does not add
metal but rather fuses the two materials. In cases where it is critical to avoid fluid intermixing, a
double tube sheet can be provided. In this design, the outer tube sheet is outside the shell circuit,
virtually eliminating the chance of fluid intermixing. The inner tube sheet is vented to atmosphere,
so any fluid leak is detected easily.
FIG 1.12: GROOVING IN THE TUBES
1.5.4 SHELL ASSEMBLY

The shell isconstructedeitherfrompipe upto24" or rolledandweldedplate metal.Forreasonsof
economy,lowcarbonsteel isincommonuse,butothermaterialssuitable forextremetemperature or
corrosionresistance oftenare specified.Usingcommonlyavailable shell pipe to24" dia.resultsinreduced
cost and ease of manufacturing,partlybecause theygenerallyare more perfectlyroundthanrolledand
weldedshells.Roundnessandconsistentshellinnerdiameterare necessarytominimize the space
betweenthe baffle outside edgeandthe shell,asexcessive space allowsfluidbypassandreduces
performance.Roundnesscanbe increasedbyexpandingthe shellaroundamandrel ordouble rollingafter
weldingthe longitudinal seam.Inextremecases,the shell canbe castand thenboredto the correct inner
diameter.
In applications where the fluid velocity for the nozzle diameter is high, an impingement plate is
specified to distribute the fluid evenly to the tubes and prevent fluid-induced erosion, cavitation
and vibration. An impingement plate can be installed inside the shell, eliminating the need to install
a full tube bundle, which would provide less available surface. Alternatively, the impingement
plate can be installed in a domed area (either be reducing coupling or a fabricated dome) above the
shell. This style allows a full tube count and therefore maximizes utilization of shell space
(figure1.13).
FIG 1.13: FLUID DISTRIBUTION TO TUBES BY IMPINGIMENT PLATE
1.5.5 END CHANNELS AND BONNETS
Used to control the flow of the tube-side fluid in the tube circuit, end channels or bonnets typically
are fabricated or cast. They are attached to the tube sheets by bolting with a gasket between the two
metal surfaces. In some cases, effective sealing can be obtained by installing an O-ring in a
machined groove in the tube sheet.
The head may have pass ribs that dictate whether the tube fluid makes one or more passes through
the tube bundle sections (figure 3). Front and rear head pass ribs and gaskets are matched to

provide effective fluid velocities by forcing the flow through various numbers of tubes at a time.
Generally, passes are designed to provide roughly equal tube-number access and to ensure even
fluid velocity and pressure drop throughout the bundle. Even fluid velocities also affect the film
coefficients and heat transfer rate so that accurate prediction of performance can be readily made.
Designs for up to six tube passes are common. Pass ribs for cast heads are integrally cast, then
machined flat while pass ribs for fabricated heads are welded into place. The tube sheets and tube
layout in multipass heat exchangers must have provision for the pass ribs. This requires either
removing tubes to allow a low cost straight pass rib, or machining the pass rib with curves around
the tubes, which is more costly to manufacture. Where a full bundle tube count is required
to satisfy the thermal requirements, the machined pass rib approach may prevent having to consider
the next larger shell diameter.
Cast head materials typically are used in smaller diameters to around 14" and are made from iron,
ductile iron, steel, bronze or stainless steel. Typically, they have pipe-thread connections. Cast
heads and tube side piping must be removed to service tubes. Fabricated heads can be made in a
range of configurations, including metal cover designs that allow servicing the tubes without
disturbing the shell or tube piping. Heads can have axially or tangentially oriented nozzles, which
typically are ANSI flanges.
FIG 1.14: PASS RIBS
1.5.6 BAFFLES

Baffles serve two important functions. First, they support the tubes during assembly and operation
and help prevent vibration from flow-induced eddies. Second, they direct the shell-side fluid back
and forth across the tube bundle to provide effective velocity and heat transfer rates.
A baffle must have a slightly smaller inside diameter than the shell's inside diameter to allow
assembly, but it must be close enough to avoid the substantial performance penalty caused by fluid
bypass around the baffles. Shell roundness is important to achieve effective sealing against
excessive bypass. Baffles can be punched or machined from any common heat exchanger material
compatible with the shell side fluid. Some punched baffle designs have a lip around the tube hole
to provide more surface against the tube and eliminate tube wall cutting from the baffle edge. The
tube holes must be precise enough to allow easy assembly and field tube replacement yet minimize
the chance of fluid flowing between the tube wall and baffle hole.
Baffles do not extend edge to edge but have a cut that allows shell-side fluid to flow to the next
baffled chamber (figure 4). For most liquid applications, the cuts areas represent 20 to 25% of the
shell diameter. For gases, where a lower pressure drop is desirable, baffle cuts of 40 to 45% are
common. Baffles must overlap at least one tube row in order to provide adequate tube support.
They are spaced somewhat evenly throughout the tube bundle to provide even fluid velocity and
pressure drop in each baffled tube section.
FIG 1.15: DOUBLE SEGMENTAL BAFFLE ARRANGEMENT
NOTE :- The arrangementon which we are going to base our analysis has 3
baffles and 6 tubes.

Chapter-2
LITERATURE SURVEY
1. The development of fluid flow and temperature profiles of a fluid after undergoing a sudden
change in wall temperature is dependent on the fluid properties as well as the temperature of the
wall. This thermal entrance problem is well known as the Graetz Problem. From reference [1] for
incompressible Newtonian fluid flow with constant ρ and k,The velocity profile can also be
developing and can be used for any Prandtl number material assuming the velocity and temperature
profiles are starting at the same point .For the original Graetz problem, Poiseuille flow was
assumed and equation was used to describe the fully developed velocity field of the fluid flowing
through the constant wall temperature tubing. Analyzing the paper from Sellars where he extends
the Graetz problem, this equation for velocity is also used. For the purposes of this paper and the
use of the finite element program, a constant value for the inlet velocity was used. This means a
modified Graetz problem was introduced and analyzed. In the cases studied, engine oil was
assumed to be flowing through the inner pipe which was made of copper and cooled by the outer
concentric pipe in which water was flowing. Material properties such as dynamic viscosity,
density, Prandtl number, and thermal conductivity were obtained from reference . Graetz found a
solution in the form of an infinite series in which the eigenvalues and functions satisfied the Sturm-
Louiville system. While Graetz himself only determined the first two terms, Sellars, Tribus, and
Klein were able to extend the problem and determine the first ten eigenvalues in 1956. Even
though this further developed the original solution, at the entrance of the tubing the series solution
had extremely poor convergence where up to 121 terms would Mnotwould Mnot make the series
converge. Schmidt and Zeldin in 1970 extended the Graetz problem to include axial heat
conduction and found that for very high Peclet numbers (Reynolds number multiplied by the
Prandtl number) the problem solution is essentially the original Graetz problem. Hwang et al
measured pressure drop and heat transfer coefficient in fully developed laminar pipe flow using
constant heat flux conditions. Based on the experimental results they showed that the experimental
friction factor was in good agreement with the theoretical predictions using the Darcy equation.

Bianco et al observed only amaximum of 11% difference between single and two phase results for
the laminar regime.
2 .Abukir et al for the first time compared three different two phase models and the single phase
model in the laminar regime. Single and two phase models were found to be predicting identical
hydrodynamic fields but very different thermal ones. The expression defining the velocity
distribution in a pipe flow across turbulent flow is derived and demonstrated in Bejan, “Convective
heat transfer coefficient”,1994 . Hydro dynamically developed flow is achieved in a pipe after a
certain length i.e. entrance length Le , where the effect of viscosity reaches the centre of pipe. At
this point the velocity assumes some average profile across the pipe which is no longer influenced
by any edge effects arising from the entrance region. The flow of real fluids exhibit viscous effects
in pipe heat transfer enhancement is increased due to its flow. Here this effect is identified for
turbulent flow conditions .A closer look at all the experimental and numerical works reveals that
most of the forced convective heat transfer studies in pipe flow have been done with constant wall
flux boundary condition. So in this work, a systematic computational fluid dynamic investigation
with constant wall temperature Boundary condition has been carried out adopting the single phase
approach in the turbulent regime and the results are compared with the analytical and numerical
results available in the literature
3 .C Rajesh Babu and Santhosh Kumar Gugulothu, investigated CFD analysis of heat transfer
enhancement by using passive technique in heat exchanger. The heat transfer enhancement is
very important many engineering applications to increase the performance of heat exchangers.
The active techniques required external power like surface vibrations, electrical fields etc and
the passive techniques are those which does not required any external power but the inserts
are required to disturb the flow like tape inserts etc moreover literature survey says passive
techniques gives more heat transfer rate without external power requirement by keeping
different tape inserts. However CFD tool is very important and effective tool to understanding
heat transfer applications. Computational heat transfer flow modelling is one of the great
challenges in the classical sciences. By incorporating the inserts the importance in different
applications. By CFD modelling by taking concentric tube by considering with and without
inserts we conclude that heat transfer enhancement by using ANSYS Fluent version 14.5.
4 A novel idea of two-phase fluid ie a liquid with nano particles present in it is conceived and this
fluid mixture is expected to give high thermal conductivity. Nano particles of metals and metal
oxides dispersed in any conventional heat transfer fluids show higher thermal conductivities when
compared to the thermal conductivities of pure liquids. In the last 100 years, a number of
theoretical and experimental studies were undertaken on the properties of liquid suspensions
containing milli or micro sized particles. Touloukian and Ho (1970) have proved experimentally
that at room temperature, the thermal conductivity of Cu is 700 times more than that of water and
3000 fold more than that of engine oil. Hamilton and Crosser (1962) and Wasp (1977) have
developed a thermal conductivity models for two-phase mixture based on their theoretical study.
Sohn and Chen (1984) investigated thermal conductivity property of solid-fluid mixture at low

velocity. At higher 7 flow rate (higher peclet number), the thermal conductivity was observed to be
increasing with increase in the shear rate. Masuda et al. (1993) studied the possibility of altering
the properties of conventional heat transfer fluids by suspending submicron particles of water
based Al203 and Ti02 and reported that the enhancement in the effective thermal conductivities are
about 32% and 11%, respectively for the nanofluids of 4.3% volume concentration.
.
5 Choi (1995) is the first researcher who worked on nano particles at the Argonne National
Laboratory, USA. He demonstrated that nanofluids exhibit an increased thermal conductivity
compared to the host fluid. Eastman et al. (1997) observed that oxide nanoparticles, such as Al2O3
and CuO have excellent dispersion properties in water, oil and ethylene glycol and form stable
suspensions. Wang et al. (1999) employed a steady state parallel plate method to measure the
effective thermal conductivity of nanofluids. They tested two types of nanoparticles, Al2O3 and
CuO, dispersed in water, engine oil, and ethylene glycol. Experimental results indicated higher
thermal conductivities in fluid mixture than those of the base fluids and the measured thermal
conductivity values are higher for nanofluids and the mixture formula under predicted experimental
thermal conductivity of the above nanofluids. Choi et al. (2001) noticed that engine oil of carbon
nanotubes and with 1.0% volume concentration exhibited 160% increment in thermal conductivity.
Das et al. (2003) employed temperature 8 oscillation technique to measure thermal conductivity of
water based Al2O3 and CuO nanofluids at different temperatures and observed a 200% to 400%
increase in the thermal conductivity of nanofluids in the temperature range of 210C to 510C. Xue
and Xu (2005) developed an effective thermal conductivity model for CuO/water and
CuO/Ethylene glycol nanofluids taking into account the thermal conductivity of the solid and
liquid, their relative volume fraction, particle size and interfacial properties.
6 .Koo and Kleinstreuer (2005) studied conduction-convection heat transfer characteristics of water–
ethylene/CuO nanofluids in micro channels and developed new models for thermal conductivity
and viscosity including the effect of viscous dissipation. Marshell et al. (2005) used spherical and
cylindrical shaped TiO2 nanoparticles in water and measured the thermal conductivities applying
hot wire method. Their results revealed that the thermal conductivity increased with increase in
particle volume fraction. The particle size and shape also have a bearing on enhancement of
thermal conductivity. The pH value and viscosity of the nanofluids are also characterized in their
experimental work.
7 .Liu et al. (2006) produced Cu nanoparticles of around 50–100 nm in diameter by chemical
reduction method and nanofluid is prepared without adding a surfactant. In a 0.1% volume
concentration Cu nanofluid, a 23.8% enhancement in the nanofluid thermal conductivity was
reported by them. Wang et al (2006) measured 9 thermal conductivities of Carbon Nano Tubes
(CNT) in water, CuO in water, SiO2 in water, and CuO in ethylene glycol by transient hot-wire
method and reported 11.3% improvement in the thermal conductivity of water-based CNT
nanofluids with 0.01% volume concentration. The measured thermal conductivity found to be
relatively higher than the thermal conductivity calculated using Hamilton–Crosser conductivity
model.

8 Beck et al. (2007) measured the thermal conductivity of ethylene glycol based alumina nanofluids
in the temperature range of 298 to 411K using a transient hot wire method. Higher thermal
conductivities were reported for all concentrations of nanofluids compared to the base liquid.
9. Casquillas et al. (2007) conducted experiments on thermal conductivity properties of ethylene
glycol based nanofluids of carbon nanotubes at droplet level and found that nanotubes
concentration has a strong effect on thermal conductivity. Chen et al. (2007) studied and measured
shear viscosity of ethylene glycol-titania nanofluids upto 8% percent on particle weight basis and
concluded that the shear viscosity of the nanofluids is a strong function of particle concentration
and nanofluid temperature. Honga et al. (2007) worked on nanofluids containing carbon nanotubes
and Fe2O3 particles and brought to light that the thermal conductivity of nanofluids can be
improved by applying external magnetic field. He reasoned that the Fe2O3 particles align in the
form of chains under applied magnetic 10 field and help to connect the nanotubes, which results in
enhanced thermal conductivity.
10 Qiuwang Wang et al. has investigated a combined multiple shell-pass shell-and-tube heat
exchanger (CMSPSTHX) with continuous helical baffles in outer shell pass has been invented to
improve the heat transfer performance and simplify the manufacture process. The CMSP-STHX is
compared with the conventional shell- and tube heat exchanger with segmental baffles (SG-STHX)
by means of computational fluid dynamics (CFD) method. The numerical results show that, under
the same mass flow rate M and overall heat transfer rate Q_m, the average overall pressure drop
∆P_m of the CMSP-STHX is lower than that of conventional SG-STHX by 13% on average.
Under the same overall pressure drop ∆P_m in the shell side, the overall heat transfer rate Q_m of
the CMSP-STHX is nearly 5.6% higher than that of SG-STHX and the mass flow rate in the
CMSP-STHX is about 6.6% higher than that in the SG-STHX. The CMSP-STHX might be used to
replace the SG-STHX in industrial applications to save energy, reduce cost and prolong the service
life .
11. Huadong Li et al. has investigated local heat transfer and pressure drop for different baffle
spacing in the shell and tube heat exchangers with segmental baffles. The distributions of the local
heat transfer coefficients on each tube surface were determined and visualized by means of mass
transfer measurements. The determination of the shell-side flow distributions are allowed by the
local pressure measurements. For same Reynolds number, the pressure drop and average heat
transfer are increased by an increased baffle spacing which can increase the heat transfer
coefficient in the whole baffle compartment due to the reduction of the percentage of the leakage
stream and due to the higher flow velocity through the baffle opening and the local heat transfer
coefficient distribution for individual tube is slightly affected by the baffle spacing.
12. Simin Wang et al. has investigated that the shell-and tube heat exchanger was improved
through the installation of sealers in the shell-side. They are cheap, firm and convenient to install.

Sealers effectively decreases the short-circuit flow in the shell-side and decrease the circular
leakage flow. The original shortcircuit flow then participates in heat transfer, which intensifies the
heat transfer performance inside the heat exchanger. The results of heat transfer experiments show
that the shell-side heat transfer coefficient of the improved heat exchanger increased by 18.2–
25.5%, the overall coefficient of heat transfer increased by 15.6–19.7%, and the energy efficiency
increased by 12.9–14.1%. Pressure losses increased by 44.6–48.8% with the sealer installation, the
energy utilization improves, which is of significance of the optimum design to the shell-and-tube
heat exchanger. The sealers are a solution settling the puzzle of the effect of baffle-shell leakage
flow in tube-and shell heat exchangers. The heat transfer performance of the improved heat
exchanger is increased, which is a benefit for optimizing of heat exchanger design.
13. J.S. Jayakumar et al. has established that heat transfer in a helical coil is higher than that in a
corresponding straight pipe. However, the detailed characteristics of fluid flow and heat transfer
inside helical coil is not available from the present literature. This paper brings out clearly the
variation of local Nusselt number along the length and circumference at the wall of a helical pipe.
Movement of fluid particles in a helical pipe has been traced. CFD simulations are carried out for
vertically oriented helical coils by varying coil parameters such as (i) pitch circle diameter, (ii)
tube pitch and (iii) pipe diameter and their influence on heat transfer has been studied. After
establishing influence of these parameters, correlations for prediction of Nusselt number has been
developed. A correlation to predict the local values of Nusselt number as a function of angular
location of the point is also presented.
14. A.E. Zohir ,The analysis of the Heat transfer characteristics in a heat exchanger for turbulent
pulsating water flow with different amplitudes has been carried out. The effect of pulsation on the
heat transfer rates, for turbulent water stream with upstream pulsation of different amplitudes, in a
double- pipe heat exchanger for both parallel and counter flows, with cold water on the shell side,
was investigated. The heat transfer coefficient was found to increase with pulsation, with the
highest enhancement observed in the transition flow regime. The heat transfer coefficient was
strongly affected with pulsation frequency, amplitude and Reynolds number. In the counter flow,
the enhancements in heat transfer rates are somewhat greater than that in the parallel flow. The heat
transfer coefficient was found to increase with pulsation, with the highest enhancement observed in
the transition flow regime. The results showed that an enhancement in relative average Nusselt
number of counter flow up to 10 times was obtained for higher amplitude and higher pulsation
frequencies. While, an enhancement in relative average Nusselt number of parallel flow up to
8 times was obtained for higher amplitude and higher pulsation frequency. The maximum
enhancements in the heat transfer rates were obtained at Reynolds number of 3855 and 11570.
15. Kevin M. Lunsford et al. has analyzed to increase the heat exchanger performance and suggested
increasing heat exchanger performance through a logical series of steps. The first step considers if
the exchanger is initially operating correctly. The second step considers increasing pressure drop if
available in exchangers with single-phase heat transfer. Increased velocity results in higher heat
transfer coefficients, which may be sufficient to improve performance. Next, a critical evaluation
of the estimated fouling factors should be considered. Heat exchanger performance can be

increased with periodic cleaning and less conservative fouling factors. Finally, for certain
conditions, it may be feasible to consider enhanced heat transfer through the use of finned tubes,
inserts, twisted tubes, or modified baffles.
16 .Apu Roy, D.H.Das has carried out with a view to predicting the performance of a shell and finned
tube heat exchanger in the light of waste heat recovery application. Energy available in the exit
stream of many energy conversion devices such as I.C engine gas turbine etc goes as waste, if not
utilized properly. The performance of the heat exchanger has been evaluated by using the CFD
package fluent 6.3.16 and the available values are compared with experimental values. By
considering different heat transfer fluids the performance of the above heat exchanger can also be
predict. The performance parameters of heat exchanger such as effectiveness, overall heat transfer
coefficient, energy extraction rate etc, have been taken in this work.

CHAPTER-3
PROPOSED METHODOLOGY
3.1 FORMULATION AND DESCRIPTION OF THE PROBLEM
3.1.1 PROBLEMDEFINITION
To perform CFD Analysis and compare nanofluids with conventional fluids (water and air) and
find the best coolant among them.
3.1.2 PROBLEM OBJECTIVES
The various objectives which are kept in mind are as follows:-
i. Testing various materials (alloys of Cr, Mo, W,V,Ni and galvanised steel) of exchanger tubes and
their effects on heat transfer rate in a parallel flow heat exchanger.
ii. Testing various fluids ( nanofluids vs conventional fluids) used as coolants in heat exchangers and
their effects on heat transfer rate in a parallel flow heat exchanger.
iii. Finding out the most economical materials,fluids to be used in a parallel flow heat exchanger to
minimise heat loss and maximise heat transfer rate using CFD analysis.
3.1.3 PROBLEMIDENTIFICATION

The single pipe heat exchanger is used in industry such as condenser for chemical process and
cooling fluid process. This single pipe heat exchanger is designed in a large size for large
application in industry. To make this small single pipe heat exchanger type becomes practicality,
the best design for this small single pipe heat exchanger is choosen.
Heat transfer is considered as transfer of thermal energy from 1 body to another. Heat transfer is
the most important parameter to be measured as the performance and the efficiency of the shell and
tube heat exchanger. By using CFD Simulation software,it can reduce the time and operation cost
compared by analytical calculations in order to measure the optimum parameter and the behaviour
of this type of heat exchanger.
3.1.4 ASSUMPTIONS
DIMENSIONS:-
• Length of Tube :- 18ooomm (approx)
• Internal Diameter of tube :- 980mm (approx)
• Outer Diameter :- 1000mm (approx)
• Baffle spacing :- 0.6 x inside shell dia =0.6x980mm= 588mm (approx)
• Weight of the tare system (without fluids) :- 13000kg(approx)
• Mass Flow Rate:- 7.56 kg/s
IMPORTANT CONSIDERATIONS:
 Scale-up i.e. laboratory scale (‘kilo lab’) to pilot plant scale (250 litres) to full plant scale
operation (10000 litres)
 Energy usage and energy costs.
 Process design and development

3.2 PROPOSED METHODFOR PROBLEM
1. Logarithmic Mean Temperature Difference (LMTD) Method
2. Heat exchanger effectiveness method
3. Effectiveness and number of transfer units[NTU]
3.2.1 LOGARITHMIC MEAN TEMPERATURE DIFFERENCE (LMTD)Method
1 Exchange between two fluids, the temp. of the fluids change in the direction of flow and
consequently there occurs a change in the thermal load causing the flow of heat.
2. fig.(a ) represents the temp. conditions existing in surface condenser or fed water heater .
3. The hot fluid is steam and the cold fluid is water. Here the temp. of steam remains constant but the
temp. of water is progressively rising.
4. During heat exchange in evaporation of water into steam fib(b) , the water evaporate at constant
temp. and the temp. of hot gases continually decreases in flowing from inlet to outlet.
CONDENSATION AND EVAPORATION

3.2.2 EFFECTIVENESS METHOD
3.2.3 Effectiveness and number of transfer units[NTU]

3.3:CATIA
CATIA (an acronym of computer-aided three-dimensional interactive application) is a multi-
platform software suite for computer-aided design (CAD), computer-aided
manufacturing (CAM), computer-aided engineering (CAE), PLM and 3D, developed by the French
company Dassault Systèmes.
3.3.1 DESIGNING IN CATIA:
CATIA offers a solution to shape design, styling, surfacing workflow and visualization to create,
modify, and validate complex innovative shapes from industrial design to Class-A surfacing with
the ICEM surfacing technologies. CATIA supports multiple stages of product design whether
started from scratch or from 2D sketches(blueprints).
3.3.2 FILE COMPATIBILITYAND CATIA V5 CONVERSION:
Dassault Systèmes provides utilities to convert CATIA V4 data files so they are accessible to
CATIA V5 and CATIA V6. Still, cases show that there can be issues in the data conversion from
CATIA V4 to V5 from either differences in the geometric kernel between CATIA V4 and CATIA
V5 or by the modelling methods employed by end users. The percentage loss can be minimized by
using the appropriate pre-conversion clean-up, choosing the appropriate conversion options, and
clean-up activities after conversion.
Conversion from CATIA Version 4 to Version 5 created construction problems for the
Airbus A380 aircraft. These problems resulted in $6.1B of additional costs due to years of project
delays when aircraft wiring was too short to make connections.
Transition from V5 to V6 is facilitated because they are sharing the same geometric
kernel. Third-party file translators also up-convert CATIA files between versions.
3.3.3 SYSTEMS ENGINEERING

The CATIA Systems Engineering solution delivers a unique open and extensible systems
engineering development platform that fully integrates the cross-discipline modeling, simulation,
verification and business process support needed for developing complex ‘cyber-physical’
products. It enables organizations to evaluate requests for changes or develop new products or
system variants utilizing a unified performance based systems engineering approach. The solution
addresses the Model Based Systems Engineering (MBSE) needs of users developing today’s smart
products and systems and comprises the following elements: Requirements Engineering, Systems
Architecture Modeling, Systems Behavior Modeling & Simulation, Configuration Management &
Lifecycle Traceability, Automotive Embedded Systems Development (AUTOSAR Builder) and
Industrial Automation Systems Development (ControlBuild).
CATIA uses the open Modelica language in both CATIA Dynamic Behavior Modeling
and Dymola, to quickly and easily model and simulate the behavior of complex systems that span
multiple engineering discipline. CATIA & Dymola are further extended by through the availability
of a number of industry and domain specific Modelica libraries that enable user to model and
simulate a wide range of systems – ranging from automotive vehicle dynamics through to aircraft
flight dynamics.
3.3.4 CATIA IN MECHANICAL ENGINEERING
CATIA enables the creation of 3D parts, from 2D sketches, sheetmetal, composites, molded, forged or
tooling parts up to the definition of mechanical assemblies. The software provides advanced
technologies for mechanical surfacing & BIW. It provides tools to complete product definition, including
functional tolerances as well as kinematics definition. CATIA provides a wide range of applications for
tooling design, for both generic tooling and mold & die. In the case of Aerospace engineering an
additional module named the aerospace sheetmetal design offers the user combine the capabilities of
generative sheetmetal design and generative surface design.
3.3.5 CATIA IN INDUSTRY
CATIA can be applied to a wide variety of industries, from aerospace and defense, automotive, and
industrial equipment, to high tech, shipbuilding, consumer goods, plant design, consumer packaged
goods, life sciences, architecture and construction, process power and petroleum, and services.
CATIA V4, CATIA V5, Pro/ENGINEER, NX (formerly Unigraphics), and Dassault Systèmes'
own SolidWorks platform are the dominant systems.

FIG 3.4:TUBE TYPE HEAT EXCHANGER DESIGNED IN CATIA
3.3.6 CATIA IN FLUID SYSTEMS:
CATIA v5 offers a solution to facilitate the design and manufacturing of routed systems including
tubing, piping, Heating, Ventilating & Air Conditioning (HVAC). Capabilities include
requirements capture, 2D diagrams for defining hydraulic, pneumatic and HVAC systems, as well
as Piping and Instrumentation Diagram (P&ID). Powerful capabilities are provided that enables
these 2D diagrams to be used to drive the interactive 3D routing and placing of system
components, in the context of the digital mockup of the complete product or process plant, through
to the delivery of manufacturing information including reports and piping isometric drawings.
3.4 BASIC COMMANDS IN CATIA:
1 PAD COMMAND
In most CAD software, the equivalent of this is called EXTRUDE, but in CATIA we call it PAD.
PAD command adds material in the third direction, a direction other than the sketch. The cube
below was made using the PAD command.

FIG 3.5: PAD COMMAND
2 POCKET COMMAND
In CATIA,The POCKET command is somehow the opposite of PAD command. It simply helps
remove geometry belonging to an already create part.
On the figure below the POCKET command is helping us to create the cylindrical hole in the
middle of the cube.
FIG 3.6: POCKET COMMAND

3 SHAFT COMMAND
Similar to REVOLVE command in other CAD software, the SHAFT command is mostly used to
make shaft like parts. It requires an axis, around which the sketch will be revolved.
FIG.3.7: SHAFT COMMAND
4 GROOVE COMMAND
As said earlier, there is another command in CATIA to subtract geometry from shaft like
components, called GROOVE. This command allows you to remove material by revolving a
sketch.
5 RIB command
The command which is usually known as SWEEP is called RIB in CATIA. It adds material along a
guide curve (which can be a straight line, arc or may be a spline). RID is used to make
components like springs, pipes etc.

FIG 3.8:RIB COMMAND
6 SLOT command
Slot removes the material along a guide curve.
FIG 3.9: SLOT COMMAND

Note: In Part Designworkbench, when you click on Sketch , the workbench will change
to Sketcher. To return from Sketcher to Part Design, you have to exit workbench using
option.
3.5 ANSYS
It develops and markets engineering simulation software. Ansys software is used todesign products
and semiconductors, as well as to create simulations that test a product's durability, temperature
distribution, fluid movements, and electromagneticproperties.
3.5.1 ANSYS Command File Creation and Execution
3.5.1.1 Generating the Command File
There are two choices to generate the command file:
1. Directly type in the commands into a text file from scratch. This assumes a good knowledge of the
ANSYS command language and the associated options.
If you know what some of the commands and are unsure of others, execute the desired operation
from the GUI and then go to File -> List -> Log File. This will then open up a new window
showing the command line equivialent of all commands entered to this point. You may directly cut
and paste from here to a text editor, or if you'd like to save the whole file, see the next item in this
list.
2. Setup and solve the problem as you normally would using the ANSYS graphic user interface
(GUI). Then before you are finished, enter the command File -> Save DB Log File This saves the
equivalent ANSYS commands that you entered in the GUI mode, to a text file. You can now edit
this file with a text editor to clean it up, delete errors from your GUI use and make changes as
desired.
3.5.1.2Running the Command File
To run the ANSYS command file,
 save the ASCII text commands in a text file; e.g. frame.cmd

 start up either the GUI or text mode of ANSYS
3.5.1.3 GUI Command File Loading
To run this command file from the GUI, you would do the following:
 From the File menu, select Read Input from.... Change to the appropriate directory where the file
(frame.cmd) is stored and select it.
 Now ANSYS will execute the commands from that file. The output window shows the progress of
this procedure. Any errors and warnings will be listed in this window.
 When it is complete, you may not have a full view of your structure in the graphic window. You
may need to select Plot -> Elements or Plot -> Lines or what have you.
 Assuming that the analysis worked properly, you can now use the post-processor to view element
deflections, stress, etc.
 If you want to fix some errors or make some changes to the command file, make those changes in a
separate window in a text editor. Save those changes to disk.
 To rerun the command file, you should first of all clear the current model from ANSYS. Select File
-> Clear & Start New.
 Then read in the file as before File -> Read Input from...
3.5.1.4 CommandLine File Loading
Alternatively, you can also read in the command file right from the ANSYS command line.
Assuming that you started ANSYS using the commands...
/ansys52/bin/ansysu52
and then entered
/show,x11c
This has now started ANSYS in the text mode and has told it what graphic device to use (in this
case an X Windows, X11c, mode). At this point you could type in /menu,on, butyou might not
want to turn on the full graphic mode if working on a slow machine or if you are executing the
program remotely. Let's assume that we don't turn the menu mode on...
If the command file is in the current directory for ANSYS, then from the ANSYS input window,
type
/input,frame,cmd

and yes that is a comma (,) between frame and cmd. If ANSYS can not find the file in the current
directory, you may need to point it to the proper directory. If the file was in the
directory, /myfiles/ansys/frame for example, you would use the following syntax
/input,frame,cmd,/myfiles/ansys/frame
If you want to rerun a new or modified file, it is necessary to clear the current model in memory
with the command
/clear,start
This full procedure of loading in command files and clearing jobs and starting over again can be
completed as many times as desired.
One of the most powerful things about ANSYS Mechanical is the fact that it creates an input file
that is sent to ANSYS Mechanical APDL (MAPDL) to solve. This is awesome because you as a
user have complete and full access to the huge breadth and depth available in the MAPDL
program. MAPDL is a good old-fashioned command driven program that takes in text commands
one line at a time and executes them. So to access all those features, you just need to enter in the
commands you want.
FIG 3.10: TEMP ESTIMATION AT EXTREMETIES IN ANSYS
3.6 COST OF PROJECT:

The costinvolve in purchasing different material and components is tabulated
below:
TABLE 3.1: MATERIAL AND THEIR COSTS
SNO MATERIAL USED QUANTITY COST(RS)
1. LAPTOP 1 40000
2. CATIA V5 [STUDENT
VERSION]
1 1500
3. ANSYS
SOFTWARE[STUDENT
VERSION]
1 2000
5. PEN DRIVE 2 650
TOTAL 44150

CHAPTER 4
DESIGNING (MODELLING) AND ANALYSIS
4.1 SELECTION OF MATERIALS
From a variety of materials shortlisted for our project , we are basing our project on alloy of
Cromium(Cr), Tungsten(W), Nickel(Ni),Vanadium(v) , Molybednum(Mo) with galvanised steel.
4.2 SELECTION OF FLUIDS/COOLANTS
In the current project we are going to select Nanofluid(CuO) ,water and air as coolants . The water
and air are called conventional fluids. At the end , we will be comparing Nanofluids with
conventional fluids on the basis of heat transfer rate in terms of effectiveness.
FIG 4.1: GALVANISED STEEL SHEET

FIG 4.2: NANOFLUID (CuO)
4.3 DESIGNING OF MODEL IN CATIA V5
Based on the above data, in this paper work has taken steel 1008 material for shell, copper and
brass material for tube. Hence these materials have good working properties compared to the other
materials such as Silver, Cast Iron, Aluminum etc. CATIA version is a process-centric computer-
aided design/computer-assisted manufacturing/computer-aided engineering (CAD/CAM/CAE)
system that fully uses next generation object technologies and leading edge industry standards.
Seamlessly integrated with D assault systems Product Lifecycle Management (PLM) solutions, it
enables users to simulate the entire range of industrial design processes from domains (elements) in
order to facilitate the numerical solution of initial concept to product design, analysis, assembly,
and a partial differential equation. The CATIA V5 product line covers mechanical and shape
“Optimal Design and Performance Analysis of Heat Exchangers Using Catia and Ansys” A. Nalini
deepthi, K. Ashok, P. Anudeep, S. Upendar “Optimal Design and Performance Analysis of Heat
Exchangers Using Catia and Ansys” 51 www.erpublication.org design, styling, product synthesis,
equipment and systems engineering, NC manufacturing, analysis and simulation, and industrial
plant design

4.3.1 DATA COLLECTION AND MODELLING
Basedon the above data,in thispaperworkhas takensteel 1008 material forshell,copperandbrass
material fortube.Hence these materialshave goodworking propertiescomparedtothe othermaterials
such as Silver,CastIron,Aluminumetc.CATIA versionisaprocess-centriccomputer-aided
design/computer-assistedmanufacturing/computer-aidedengineering(CAD/CAM/CAE) systemthatfully
usesnextgenerationobjecttechnologiesandleadingedge industrystandards.Seamlesslyintegratedwith
DassaultSystemsProductLifecycle Management(PLM) solutions,itenablesuserstosimulate the entire
range of industrial designprocessesfromdomains(elements)inorderto facilitate the numerical solution
of initial concepttoproductdesign,analysis,assembly,andapartial differentialequationmaintenance.
i. DIMENSIONSOF SHELL AND TUBE HEAT EXCHANGERS
No. of baffles = 3
No. of tubes = 6
Length of the tubes = 18000 mm
Tube internal diameter = 980 mm
Tube external diameter = 1000 mm
Clearance = 1000-980 = 20 mm
Tube layout = 90
Shell length = 18600 mm
Shell diameter = 1000 mm
Thickness = 1200 mm
NOMENCLATURE:
E - Young’s Modulus
μ -Poisson’s ratio
K -Thermal conductivity
ρ- Density
Cp -Specific heat Thermal properties of copper and brass
TABLE 4.1: GEOMETRY DEFINING

OBJECT NAME SOLID
STATE MESHED
TABLE 4.2 :COORDINATE DEFINING
Object Name Global Coordinate System
State Fully Defined
Object Name
Temperature
Total Heat
Flux
State Solved
Scope
Scoping Method Geometry Selection
Geometry All Bodies
Definition
Type Temperature Total Heat
Flux
By Time
Display Time Last
Calculate
Tim
e History
Yes
Identifier
Suppressed No
Results
Minimum 110.63 °C
7.9493e-
004
W/mm²
Maximum 120. °C
8.9392e-
004
W/mm²
Information
Time
1. s
Load Step 1

Definition
Sub step 1
Iteration Number 2
Integration Point Results
Display Option Averaged
Type Cartesian
Coordinate System
ID
0
.
Origin
Origin X 0. Mm
Origin Y 0. Mm
Origin Z 0. mm
Directional Vectors
X Axis Data [ 1. 0. 0. ]
Y Axis Data [ 0. 1. 0. ]
Z Axis Data [ 0. 0. 1. ]
TABLE 4.3: STEADY STATE THERMAL SOLUTIONS

4.4 IMPORTING DATAFROM CATIA TO ANSYS
NOW ANSYS IS OPENED AND THE PREVIOUSLY MADE MODEL IN CATIA V5 IS
IMPORTED IN ANSYS VIA THE CALLING COMMAND.
FIG 4.3: CALLING MODEL IN ANSYS
4.5 DEFINING MATERIALPROPERTIES
Water was used as the base fluid flowing through tubing or piping. Its material properties were
derived from tables based on the temperature which was being calculated in the model. The
material was defined in FLUENT using its material browser. For the different flow arrangement
problem model certain properties were defined by the user prior to computing the model, these
properties were: thermal conductivity, density, heat capacity at constant pressure, ratio of specific
heats, and dynamic viscosity. For the modified Graetz problem with pipe wall conduction as well
as for the heat exchanger models the material library properties in FLUENT were used.
TABLE 4.4: DEFINING FLUID PROPERTIES

Different Density
Thermal Specifi Dynamic
conducti c heat viscosity
fluids (ρ) Pr
vity(K) CP (μ)
propertie
s kg/m3
W/mk j/kgK kg/m-s
Transfor
mer
826 159 0.134 2328 0.0091
oil
T
B
A
Nanoflu
id
(CuO) 900 190 0.123 3430 0.00333
Benzene 875 6.51 0.159 1759 0.00058
Gas oil 830 50.4 0.135 2050 0.00332
Ethylene
1111.4 150.4 0.252 2415 0.0157
glycol
Glycerin 1259.9 6780.3 0.286 2427 0.799

Water 998.2 6.99 0.6 4182 0.001003
Differe
nt
Densit
y
Therma
l Specific
materia
l
conductivi
ty(K) heat CP3
propert
ies
(ρ)
kg/m
W/mk j/kgK
Alloy
used 8978 387.6 381
Galvani
sed 2719 203.2 871
4.6 SIMULATION
4.6.1 FINITE VOLUME METHOD:
The mass, momentum, and scalar transport equations are integrated over all the fluid elements
in a computational domain using CFD. The finite volume method is a particular finite
differencing numerical technique, and is the most common method for calculating flow in CFD
codes. This section describes the basic procedures involved in finite volume calculations.

The finite volume method involves first creating a system of algebraic equations through the
process of discretising the governing equations for mass, momentum, and scalar transport. To
account for flow fluctuations due to turbulence in this project, the RANS equations are discretised
instead when the cases are run using the k-epsilon turbulence model. When the equations have been
discretised using the appropriate differencing scheme for expressing the differential expressions in
the integral equation (i.e. central, upwind, hybrid, or power-law, or other higher-order differencing
schemes), the resulting algebraic equations are solved at each node of each cell.
FIG 4.4: SIMULATION IN ANSYS
FIG 4.5: MODEL FINISHING IN ANSYS

FIG 4.6: FINISHED MODEL OF HEAT EXCHANGER IN ANSYS IN VOLUME
PROFILE

CHAPTER 5
CALCULATION AND RESULT
DIMENSIONS:-
• Length of Tube :- 18ooomm (approx)
• Internal Diameter of tube :- 980mm (approx)
• Outer Diameter :- 1000mm (approx)
• Inlet Pressure (hot fluid) :- 50 psi
• Inlet Pressure (cold fluid) :- 50 psi
• No. of tubes :- 6
• No. of Baffles :- 3
• Hot fluid Inlet Temperature:- 344 K
• Cold Fluid Inlet Temperature :-290 k
• Baffle spacing :- 0.6 x inside shell dia =0.6x980mm= 588mm (approx)
• WEIGHT OF THE TARE SYSTEM (without fluids) :- 13000kg(approx)
• MASS FLOW RATE:- 7.56 kg/s
CONSTRAINTS
Important consideration in:
 Scale-up i.e. laboratory scale (‘kilo lab’) to pilot plant scale (250 litres) to full plant scale
operation (10000 litres)

 Energy usage and energy costs.
 Process design and development
5.1 CALCULATION
• Fig. represent the block diagram of HE. The indicated parameter are:
m= mass flow rate (kg/s)
c = specific heat (j/kg-deg)
t = fluid temp.(◦c)
∆t = Temp. drop or rise of a fluid across the HE

5 .1.1 Graetzproblem calculations:

At velocity V=0.0001m/s
Reynolds number
Re = ρvD/ μ
= (988x0.0001x0.1) / (5.47x10-4) =18.062 Now Pr = Cp μ/K
= (4181X5.47X10-4)/0.64 = 3.57
Dimensionless lengthvalue
L* =L/DRePr
= 1/ (0.1x18.062x3.57) = 0.1556
Nusseltnumber
Num = 3.66 + {(0.075/ L*)/ (1+ (0.05/ (L*) ^ (2/3)}
=4.072
Num = (-1/4 L*) x (ln (Tm*(L)
Tm*(L) = e-4 L* Num =0.0793
Tm (L) = Tw-(Tw-To) X Tm*(L)
= 30-(30-50) x0.0793 =31.6oc =304.67 k

FIG 5.1: MODIFIED GRAETZ PROBLEM ANSYS WORKBENCH MODEL
LAMINAR FLOW IN PARALLEL FLOW HEAT EXCHANGER
PROBLEM CALCULATIONS:
At velocity V=0.0001m/s
DO = 0.14m Di = 0.1m
AO = 0.4398 m2 Ai =0.3142
m2
Cross sectional area of each fluid flow Aoil = πr2 = 0.00785m2
Awater = π (ro
2-ri
2) = 0.02985 m2
GRAPH 1 : TEMPERATURE AND VELOCITY FOR A TURBULENT PARALLEL
FLOW HEAT EXCHANGER

CFD ANALYSIS OF PARALLEL FLOW HEAT
EXCHANGER
ME DEPARTMENT,SRMGPC,LUCKNOW
Moil= ρAv= (826). (0.007854).(0.0001)=0.0006487 kg/s Mwater= ρAv= (998.2).
(0.02984).(0.0001)=0.00297 kg/s
Heat capacity rates.
Coil = Cpoil × Moil = 2328×0.0006487=1.51W/K
Cwater=Cp, water× Mwater =4182×0.002979 =12.45 W/K Ratio of heat capacity:
Cr=Cmin/Cmax= Coil/ Cwater=0.1212
Reynolds number
Re = ρvD/ μ
=(4 x Moil)/ (π Di μoil)
=(4x0.0006487)/ (π x 0.1 x0.00915) = 0.902

Nusselt Number
Nu = 3.66 + (0.0668A/ (1+ (0.4 X A0.667))
=4.435
A = Re Pr (Di/L) =14.35 m2
Heat transfer coefficient
The inner pipe wall is:
hi = Koil x Nu/ Di
= (0.134 x 4.435)/0.1 =5.942 w/m2k
Designoverall heat transfer coefficient
UA = 1/{(1/ hi Ai)+(1/ ho Ao)+( ln(DO/ Di)/2 πLKcopper)}
=0.7687 w/k
Number of transfer units
NTU = UA/Cmin = 0.7687/1.5102 = 0.509
Effectiveness
έ= 1- e {-NTU (1+Cr)}/ (1+Cr)
=1- e {-0.59 (1+0.12121)}/ (1+0.12121)
=0.3879
Heat capacity
q= έ x Cmin x (Thi-Tci)
=61.507 watts
Cold and hot fluid out let temperatures
Tco = Tci + (q/ Cmax) = 293.15 + (61.507/12.45)
=298.09 k
Tho = Thi - (q/ Cmin) =398.15 – (61.507/1.510)
=357.42 k

Log mean temperature difference
q = UA∆TLM
∆TLM=61.507/0.7687=80.017 k
∆TLM = (∆T2 - ∆T1)/ ln (∆T2/∆T1) =(357.42-298.08)-(398.15-293.15)/ln((357.42-
298.08)/(398.15-293.15))
∆TLM =80.17k
TABLE 5.1 : TEMP (celcius) VS EFFECTIVENESS FOR WATER
TEMP EFFECTIVENESS
60 0.4
77 0.57
85 0.63
TABLE 5.2: TEMP (celcius) VS EFFECTIVENESS FOR NANOFLUID
(CuO)
TEMP EFFECTIVENESS
60 0.6
77 0.83
85 0.87
GRAPH 2 : TEMP VS EFFECTIVENESSFOR WATER

GRAPH 3:TEMP VS EFFECTIVENESS FOR NANOFLUIDS(CuO)

5.2 RESULTS
The Heat transfer rate for Nanofluids was found to be higher with an
effectiveness of approximately(0.776)almost23 percent higher than
that of conventionalfluids i.e water(with an effectiveness of 0.533).

Chapter-6
ADVANTAGES, DISADVANTAGES
AND APPLICATIONS
6.1 ADVANTAGES
Advantages of CFD Analysis of parallel flow heat exchangers are given below :-
Better cooling
High heat transfer rate.
Cost is less.
Easy maintenance and maintenance cost is less.
It resist all atmospheric effects.
6.2 DISADVANTAGES
The disadvantages of our project are as follows :-
Nanofluids are relatively new coolants with lesser demands and are not used
widely currently.
6.3 APPLICATIONS OF NANOFLUID(CuO) USED IN
PROJECT
The applications of Nanofluids used in our CFD Analysis are :-
In power plants.
In boilers
In air conditioning.

Chapter-7
CONCLUSION, FUTURE SCOPE
AND REFRENCES
7.1 CONCLUSION
CFD provides cost effective alternative, speedy solution and eliminate the need of
prototype. The literature review focus on the analysis of various parameters which
influence on the performance of the STHE.
It has been observed that computational modeling is one of the efficient techniques to
study these type of heat elements. The parameters like tube and shell diameter,
number of tubes, pitch and baffle angles are the important one to be worked upon. A
detailed analysis using the CFD simulation will be worthy to be carried out
The design and CFD analysis on shell and tube heat exchanger has been done and the
results were compared with the effectiveness NTU method. We had observed a
considerable amount of deviation from the actual value to the value that is obtained in
the simulation.
With the help of CFD Analysis ,we concluded that if we fix cold inlet and hot inlet
temperature then the value of Effectiveness is better in case of Nanofluids than that of
conventional fluids (water and air). And the degree of coolness in case of nanofluid is
more as compared to the conventional fluids.
The design and CFD analysis on shell and tube heat exchanger has been done and
the results
were compared with the effectiveness NTU method.
We had observed a considerable amount of deviation from the actual value to the
value that is obtained in the simulation.
This project has further developments like considering different types of flows like
cross, parallel and counter flow.
And also here we have considered that the radiation and convection losses as zero
where as in practical situations . Since the significance of various design soft wares is
increasing day by day this project can be executed in any kind of design softwares
like PRO-E and CATIA.

7.2 FUTURE SCOPE
1. We can measure total deformation,Factor of Safety, stresses and strain with the help
of CFD Analysis.
2. Heat transfer rate of Nanofluids is found to be better than that of conventional fluids,
hence heat transfer efficiency is higher and overall performance is enhanced. Hence
,Nanofluids can be used as heat transfer fluids in future extensively.
3. In Nanofluid used (CuO), minimum heat loss to surroundings was observed relative to
the conventional fluids , thus CuO has a scope as an effective coolant in future.

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