In the present work an attempt has been made to investigate the performance of a 3 channel 1-1 pass, corrugated plate heat exchanger. The plates had sinusoidal wavy surfaces with corrugation angle of 450. Hot water at different inlet temperature ranging from 400C to 600C was made to flow in the central channel to get cooled by water in the outer channels.
2. An Experimental Study of Exergy in a Corrugated Plate Heat Exchanger
http://www.iaeme.com/IJMET/index.asp 17 editor@iaeme.com
composed of the smooth and corrugated walls. The heat transfer performance of the
corrugated wall channel was compared with that of a smooth wall. Hamza et al. have
experimentally studied effects of the operating parameters on laminar flow forced
convection heat transfer of air flowing in a channel having a V-corrugated upper
plate. The experiments were performed for Reynolds number and tilting angles of
channel in the ranges of 750–2050, and 0–60°, respectively. To determine the optimal
design and operating conditions of heat exchangers, the performance of heat
exchanger should be evaluated correctly. It is thus needed to develop an accurate and
reliable evaluation method. Presently the evaluation criteria of the performance of
heat exchangers fall into two catalogues: the entropy evaluation method and the
exergy evaluation method. In the analysis and design of heat exchangers, it is
necessary to evaluate the entropy generation/exergy destruction due to heat exchange
and pressure drop as a function of the design variables selected for the optimization
analysis. Bejan presented a method for fixed or minimum number of entropy
generation units in counter flow heat exchangers for gas-to-gas applications. He also
investigated a heat exchanger with heat transfer loss and frictional pressure drop in
channels, and reported heat exchanger effectiveness using the entropy generation
number. Boyd et al. demonstrated that it was possible to design an optimal heat
exchanger based on the second law of thermodynamics to minimize the loss of
available work. Sarangi and Chowdhury analyzed the entropy generation in a counter
flow heat exchanger and discussed some formal mathematical consequences of
entropy generation.. Sekuli estimated the quality of the heat exchange process in heat
exchanger analysis using the entropy generation. Durmus et al studied experimentally
forced convection heat transfer and pressure drop in plate heat exchangers having
different surface profiles. The results show that the efficiency of the heat exchanger
increases with increasing the fluids' contact surface, pressure drop and mass flow rates
due to an enhanced heat transfer to the fluid. Pandey et al. carried out heat transfer
and pressure drop studies on a sinusoidal plate heat exchanger. The results show that
the results show that the average energy loss in PHE with rectangular wavy surface is
about 79.53% of that with the rectangular geometry.
2. NOMENCLATURE
A Cross sectional area, (m2
)
c Specific heat at constant pressure, (J kg-1
K-1
)
C Heat capacity rate, (W K-1
)
Dh Hydraulic diameter, (m)
E Exergy loss, (W)
h heat transfer coefficient, (W m_2
K_1
)
L length, (m)
M mass flow rate, (kg s_1
)
P Pressure, (N m_2
)
Pr Prandtl number
Q Heat transfer rate, (W)
Re Reynolds number
T Temperature, (K)
V Average velocity of fluid, (m s_1
)
ρ Density of air, (kg m_3
)
3. Mohd. Rehan Khan and Dr Ajeet Kumar Rai
http://www.iaeme.com/IJMET/index.asp 18 editor@iaeme.com
Suffixes
c Cold
e Environment, ambient
h Hot
I Inlet
max Maximum
o Outlet
min Minimum
3. EXPERIMENTAL SETUP
The photograph of the experimental setup, fabricated with 22 gauge GI sheets to
investigate the heat transfer characteristics of the plate heat exchanger channels for
same flow conditions with different inlet hot water temperatures are shown in (Figure
1). It includes a hot water loop, two coolant loop and a measurement system. The hot
water loop comprises a water tank, a heater, and a water pump. The cold water loop
comprises a water tank, and a water pump. A digital temperature indicator with
thermocouples is used to measure temperatures at inlet and exit of the hot and cold
streams. The flow rate is measured by noting down time for collection of fixed volume
of the fluid. The whole system is thermally insulated to minimize the energy loss.
Figure 1 Photographs of sinusoidal wavy corrugated plates used in plate heat exchanger.
Figure 2 Photographs of experimental setup
4. An Experimental Study of Exergy in a Corrugated Plate Heat Exchanger
http://www.iaeme.com/IJMET/index.asp 19 editor@iaeme.com
3.1. Specifications of the experimental setup
Length of the test section =100 cm
Width of the test section = 10 cm
Height of a flow channel, i.e. gap between two successive corrugated plates = 5
cm.
Chevron angle of the plate = 45o
Material of the plate is GI of 22 gauge.
3.2. Experimental procedure
Hot water was made to flow through the central corrugated channel to maintain the
channel surfaces at approximately constant temperature. Cold water is made to flow
in the upper and lower channels. Thermocouples were inserted in the inlet and exit of
the hot and cold streams, were used to record the corresponding fluid temperatures.
Thermocouples were calibrated with ZEAL thermometer. Experiments were
conducted for 40, 45, 50, 55, 60 0
C inlet temperature of hot water in parallel and
counter flow arrangement. The hot and cold water flow rate is maintained constant for
all inlet hot water temperatures and for both parallel and counter flow arrangements.
Mass flow rate of hot fluid (water) is maintained at 0.05 kg/s and that of the cold fluid
(water) is 0.16 kg/s.
3.3. Numerical Methodology
In the present experiment, flow rates of hot and cold fluids are kept constant in
parallel and counter flow arrangement. After collection of the data of temperatures at
inlet and exit of the hot and cold fluid streams, exergy losses of the two heat
exchanging fluids are calculated as given below.
Heat lost to the surroundings = heat given by hot fluid - heat taken by cold fluid
mhch=(Thi - Tho)-mccc(Tco - Tci)
Values of heat given by hot fluid and heat absorbed by cold fluid, calculated in the
present experiment showed that there was negligible loss of heat to the surroundings
due to proper insulation of the heat exchanger. For such heat exchanger,W=0 and Q =
0, and exergy loss for a steady state open system can be found as a sum of those for
the individual fluids, i.e.,
E = Eh + Ec
The exergy changes for the two fluids are obtained as given below:
For hot fluid (i.e. water),
Eh = Te[mh(sho- shi)]
or Eh = Te[Ch ln(Tho-Thi)]
and for cold fluid
Ec =Te[mc(sco- sci)]
or; Ec = Te[Cc ln(Tco/Tci)]
The exergy loss caused by pressure drop is not to be considered for liquids
because ΔE also contains the exergy loss caused by the pressure drop. Besides the
5. Mohd. Rehan Khan and Dr Ajeet Kumar Rai
http://www.iaeme.com/IJMET/index.asp 20 editor@iaeme.com
exergy loss, the effectiveness of the PHE is calculated from experimental observations
using the following equation:
Ԑ =[ Cc(Tco - Tci]/[Cmin(Thi - Tci)]
Reynolds number is calculated based on hydraulic diameter of sinusoidal wavy
PHE channel from Re =(ρVDh/µ)
Where Dh = 4(width x height)/2(width + height) and V = m/ρ(width x height)
Physical properties, ρ and m of the fluid are evaluated at its mean Bulk
temperature.
4. RESULTS AND DISCUSSION
Figure 3 shows the variation of maximum possible heat transfer rate for different inlet
temperature of hot water and for a given inlet temperature of cold water in both
parallel and counter flow arrangements. As inlet hot water temperature increases, Qmax
increases. Trend is found similar in parallel and counter flow arrangements.
Effectiveness in counter low is 44.5% more than parallel flow arrangement.
Figure 3 Variation of Qmax for different inlet hot water temperature
Figure 4 Variation of Exergy for different hot water inlet temperature
0
1000
2000
3000
4000
5000
6000
7000
40 45 50 55 60
Qmax(W)
Temperature (0C)
Parallel Flow
Counter Flow
0
20
40
60
80
100
120
140
40 45 50 55 60
Exergy(W)
Temperature 0C
Parallel Flow
Counter Flow
6. An Experimental Study of Exergy in a Corrugated Plate Heat Exchanger
http://www.iaeme.com/IJMET/index.asp 21 editor@iaeme.com
Figure 5 Variation of E/Qmax for different inlet temperature of hot water
Variation of exergy loss with hot fluid inlet temperature for a fixed cold fluid inlet
temperature is given in Figure 4 for both parallel and counter flow arrangements.
Exergy loss is less at low inlet hot temperature relative to the high inlet hot
temperature. This observation may be attributed to increased temperature resulting in
the increase in irreversibility which is responsible for increase in exergy loss. It is also
observed that with rise in inlet hot water temperature, exergy loss is more in counter
flow arrangement than in parallel flow arrangement, which is in accordance with the
results found by Pandey et. al. [2011].
Variation of Exergy loss (E/Qmax) with inlet hot water temperature is shown in
Figure 5 for a constant inlet cold water temperature. It may be seen that the (E/Qmax)
is more in parallel flow arrangement than in the counter flow arrangement.
CONCLUSION
1. A three channel 1-1 pass corrugated with corrugation angle 450
plate type heat
exchanger was fabricated.
2. Performance of plate heat exchanger at different input heat load was measured in
parallel and counter flow arrangement.
3. Exergy analysis was performed to find its behavior in parallel and counter flow
arrangement.
4. Effectiveness in counter low is 44.5% more than parallel flow arrangement.
5. Exergy loss was found 7.2% more in parallel flow than in counter flow arrangement.
REFERENCES
[1] Sunden, B. and Trollheden, S. Periodic laminar flow and heat transfer in a
corrugated two-dimensional channel. International Communications in Heat and
Mass Transfer, 16, 1989, pp. 215–225.
[2] Fabbri, G. Heat transfer optimization in corrugated wall channels. International
Journal of Heat and Mass Transfer, 43, 2000, pp. 4299–4310
[3] Hamza, A., Ali, H. and Hanaoka, Y. Experimental study on laminar flow forced-
convection in a channel with upper V-corrugated plate heated by radiation.
International Journal of Heat and Mass Transfer, 45, 2002, pp. 2107–2117.
0.01
0.012
0.014
0.016
0.018
0.02
0.022
0.024
40 45 50 55 60
E/Qmax
Temperature 0C
Parallel flow
Counter flow
7. Mohd. Rehan Khan and Dr Ajeet Kumar Rai
http://www.iaeme.com/IJMET/index.asp 22 editor@iaeme.com
[4] Bejan, A. The concept of irreversibility in heat exchanger design: counterflow
heat exchangers for gas-to-gas applications. J HeatTransfer, 99, 1977, pp. 374–
80.
[5] Bejan, A. General criterion for rating heat exchanger performance. Int.J Heat
Mass Transfer, 21, 1978, pp. 655–8.
[6] Boyd, J. M., Bluemel, V., Keil, T. H., Kucinkas, G. R. and Molinari, S. The
second law of thermodynamics as a criterion for heat exchanger design. Energy,
6(7), 1981, pp. 603–9.
[7] Sarangi, S. and Chowdhury, K. The generation of entropy in a counterflow heat
exchanger. Cryogenics, 22, 1982, pp. 63–5.
[8] Sekulic, D. P. The second law quality of energy transformation in heat exchanger.
J Heat Tranfer, 112, 1990, pp. 295–300
[9] Durmus, A., Benli, H., Kurtbas, I. and Gul, H. Investigation of heat transfer and
pressure drop in plate heat exchangers having different surface profiles. Int J
Heat Mass Transf, 52, 2009, pp. 1451–7.
[10] Pandey, S. D. and Nema, V. K. Rating of an experimental plate heat exchanger”.
In:Proceedings of national conference: advance in management of energy
efficiency and clean environment. Kanpur, India, 2010, pp. 70–75
[11] Mukherjee, P., Biswas, G. and Nag, P. K. Second law analysis of heat transfer in
swirling through a cylindrical duct. J Heat Transfer, 109, 1987, pp. 308–13.
[12] Ismael, O. M., Dr. Rai, A. K., Mahdi, H. F. and Sachan, V. An experimental
study of heat transfer in a plate heat exchange. International Journal of
Mechanical Engineering and Technology, 5(4), 2014, pp. 31–37
[13] Pandey, S. D. and Nema, V. K. An experimental investigation of exergy loss
reduction in corrugated plate heat exchanger. Energy, 36, 2011, pp. 2997–3001
[14] Kumar, A., Dr. Rai, A. K. and Sachan, V. Experimental Study of heat transfer in
a corrugated plate heat exchanger. International Journal of Mechanical
Engineering and Technology, 5(9), pp. 286–292