Most engineers involved in the planning of pumping systems are familiar with the terms water which cause series damage to pipe component such as pumps valves and cause big losses of water called water Hammer. ------------------------------------------------------------------------------------- ► You can visit my website https://bit.ly/3rNZ4Ds Follow us on ► LinkedIn: https://bit.ly/3yL9q8K ► Instagram: https://bit.ly/3yG9zdx ► YouTube: https://bit.ly/3q93r9G ------------------------------------------------------------------------------------- #Water_Hammer #Valves #Joukowsky's_equation #Hazen_Williams_Equation #Darcy-Weisbach #Cole-Brooke_Equation #Haaland_Equation #Moody_chart #elimination_water_hammer #Surge_Tank #Air valve #Pressure_relief_valve #Check_valve #Control_valve #air_vessels #WaterCAD #Water_network #Pipe #Junction #Reservoir #Bentley HAMMER

1. Water Hammer
Prepared by
Eng/Mohamed Khaled

2. Water Hammer
Most engineers involved in the planning of pumping systems are familiar with the
terms water which cause series damage to pipe component such as pumps valves and
cause big losses of water called water Hammer
INTRODUCTION:

3. Water Hammer
1. Water hammer (Hydraulic shock - fluid hammer) is a pressure surge or wave caused
when a fluid in motion is forced to stop or change direction suddenly
2. Water hammer is a series of pressure pulsations of varying magnitude above and
below the normal pressure of water in the pipe
Physical concept of water hammer

4. Water Hammer
Rapid valve open/close and change in flow rate are the most common reason to cause
the pressure surge; when direction of the flow changes, the water particles hit the pipe
walls, emitting a banging noise.

5. Water Hammer

6. Water Hammer
Water hammer can happen when:
• A pipe suddenly close at outlet (downstream).
• Valves suddenly close along the flow.
• Hydrant open/close
• Surge tank draining out
• Pump failure and check valve/air valve slam due to acceleration/deceleration.
• Common appliances like washing machine, automatic flushing toilet when suddenly
shutdown

7. Water Hammer
Parameters affecting water hammer
1. Unsteady friction model
2. Cavitation
3. Fluid–structure interaction (FSI)
4. Viscoelastic of the pipe wall
5. leakage and blockage

8. Water Hammer
1. Unsteady friction model :
Parameters affecting water hammer:
The effect of unsteady friction on water hammer waveforms is investigated using the
copper pipeline shown in Fig . The Reynolds number of the initial flow (Re) is 4360 so
that the initial flow is turbulent.

9. Water Hammer
2. Cavitation
Parameters affecting water hammer:
Cavitation occurs when the liquid in a pump turns to a vapor at low pressure. It occurs
because there is not enough pressure at the suction end of the pump, air bubbles are
created at low pressure then hit the surrounding wall

10. Water Hammer
3. Fluid–structure interaction (FSI)
Interactions between fluids and structure may be stable or oscillatory. The strain caused
in the solid structure causes it to shift in oscillatory interactions, and the structure
returns to its former state only for the process to repeat.
Parameters affecting water hammer:

11. Water Hammer
4. Viscoelastic of the pipe wall
In water supply schemes, plastic pipes are increasingly
used. Because of their high resistance (mechanical,
chemical, temperature and abrasion) and low price
characteristics. Viscoelastic pipe parts have been used
to remove dangerously large transients because of the high the dispersion and damping
presented by the pipe section’s viscoelasticity
Parameters affecting water hammer:

12. Water Hammer
5. leakage and blockage
During design lifetime, leaks and blockages reflect common faults that can be
encountered by pipeline systems. In certain instances, Transients measured in the field
represent considerably more damping that which is predicted by models
Parameters affecting water hammer:

13. Water Hammer
Governing equation of water hammer phenomena & pipeline losses:
1. Joukowsky's equation:
2. Hazen Williams Equation
3. Darcy-Weisbach Formula
4. Cole-Brooke White Equation
5. Haaland Equation

14. Water Hammer
Joukowsky's equation is a method of determining the surge pressures that will be
experienced in a fluid piping system.
ΔP=ρ a Δv
Where
a=speed of sound in a fluid (m/s)
P=Fluid pressure (Pa)
v=Fluid velocity (m/s)
ρ=Fluid density (Kg/m^3)
Governing equation of water hammer phenomena:
1. Joukowsky's equation

15. Water Hammer
𝑎 =
1
𝜌
1
𝐾
+
𝐷
𝐸𝑒
𝑚
𝑠
Where
𝐾 = 𝐵𝑢𝑙𝑘 𝑚𝑜𝑑𝑢𝑙𝑢𝑠 𝑜𝑓 𝑓𝑙𝑢𝑖𝑑
𝐸 = 𝑌𝑜𝑢𝑛𝑔’𝑠 𝑚𝑜𝑑𝑢𝑙𝑢𝑠 𝑜𝑓 𝑝𝑖𝑝𝑒 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙
𝑒 = 𝑊𝑎𝑙𝑙 𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 𝑜𝑓 𝑝𝑖𝑝𝑒
Bulk modulus =
𝑷
(𝑽𝟎−𝑽𝒏)/𝑽𝟎
Young's modulus: 𝑬 =
𝝈
𝜺

16. Water Hammer
Governing equation of water hammer phenomena:
2. Hazen Williams Equation
The Hazen–Williams equation is an empirical relationship which relates the flow of
water in a pipe with the physical properties of the pipe and the pressure drop caused by
friction. It is used in the design of water pipe systems
ℎ𝑓 = 10.675 ×
𝐿
𝐶1.852
×
𝑄1.852
𝐷4.87
Where
ℎ𝑓 = 𝑇ℎ𝑒 ℎ𝑒𝑎𝑑 𝑙𝑜𝑠𝑠 𝑑𝑢𝑒 𝑡𝑜 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 𝑚 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟
𝐿 = 𝑇ℎ𝑒 𝑝𝑖𝑝𝑒 𝑙𝑒𝑛𝑔𝑡ℎ 𝑖𝑛 𝑚
𝐶 = 𝑇ℎ𝑒 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑤ℎ𝑖𝑐ℎ 𝑑𝑒𝑝𝑒𝑛𝑑𝑠 𝑜𝑛 𝑟𝑜𝑢𝑔ℎ𝑛𝑒𝑠𝑠
𝑄 = 𝑇ℎ𝑒 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑖𝑛 𝑚3
/𝑠
𝐷 = 𝑇ℎ𝑒 𝑝𝑖𝑝𝑒 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑖𝑛 𝑚

17. Water Hammer
• Weisbach first proposed the equation we now know as the Darcy-Weisbach formula
or Darcy-Weisbach equation:
Governing equation of water hammer phenomena:
3. Darcy-Weisbach Formula
ℎ𝑓 = 𝑓 ×
𝐿
𝐷
×
𝑉2
2𝑔
Where
ℎ𝑓 = 𝑇ℎ𝑒 ℎ𝑒𝑎𝑑 𝑙𝑜𝑠𝑠 𝑑𝑢𝑒 𝑡𝑜 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 (𝑚) 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟
𝑓 = 𝑑𝑎𝑟𝑐𝑦 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑓𝑎𝑐𝑡𝑜𝑟
𝐿 = 𝑇ℎ𝑒 𝑝𝑖𝑝𝑒 𝑙𝑒𝑛𝑔𝑡ℎ 𝑖𝑛 (𝑚)
𝑉 = 𝑇ℎ𝑒 𝑓𝑙𝑜𝑤 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑖𝑛 (
𝑚
𝑠
)
𝐷 = 𝑇ℎ𝑒 𝑝𝑖𝑝𝑒 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑖𝑛 (𝑚)

18. Water Hammer
Governing equation of water hammer phenomena:
3. Cole-Brooke White Equation
The Colebrook-White equation which provides a mathematical method for calculation
of the friction factor (i.e. mathematical iteration is normally required to find f).
1
𝑓
= −2 log10
𝜀
3.7𝐷
+
2.51
𝑅𝑒 𝑓
𝑓𝑜𝑟 𝑅𝑒 > 4000
𝑓 = 64/𝑅𝑒 𝑓𝑜𝑟 𝑅𝑒 <4000

19. Water Hammer
Governing equation of water hammer phenomena:
4. haaland Equation
1
f
= −2 log
ε
3.7 D
+
4.518log(
Re
7
)
Re
(1+
Re
.
52
29
ε/D .7)
for R e> 4000
Used to calculate friction factor without Iteration

20. Water Hammer
Governing equation of water hammer phenomena:
5. Moody chart

21. Water Hammer
Devices elimination water hammer

22. Water Hammer
Devices elimination water hammer
1. Surge Tank
2. Air valve
3. Pressure relief valve
4. Check valve (non-return valve, reflux valve)
5. Control valve

23. Water Hammer
Devices elimination water hammer
1. Surge Tank
• Surge tank is a storage device used to pressurized the fluid to resist excess pressure
rise and pressure drop conditions
• There are different types of surge tanks like:
▪ Closed surge tank (air vessels).
▪ Simple surge tank.
▪ Gallery type surge tank
▪ Inclined surge tank
▪ differential surge tank

24. Water Hammer
Devices elimination water hammer
1. Surge Tank
• Closed surge tank (air vessels)
A water surge vessel is attached to the pipework of
the mains outlet, pressurized with compressed air, by
absorbing any fall, retaining the water flow and
velocity, the vessel maintains the water pressure

25. Water Hammer
1. Surge Tank
• Simple surge tank
The top of the surge tank is opened to
atmosphere pressure and when
completely fill than overflow and
maintain the pressure
Devices elimination water hammer

26. Water Hammer
1. Surge Tank
• Gallery type surge tank
This type has two chamber, the below
chamber store excess water and release it
when it required, and the upper chamber
used to absorb excess pressure
Devices elimination water hammer

27. Water Hammer
1. Surge Tank
• Inclined surge tank
in this type, the surge tank provide some
inclined and we can use it when there is
limited of the height of the tank,
Devices elimination water hammer

28. Water Hammer
1. Surge Tank
• Gallery type surge tank
These ports helps the flow into or out of the
tank, the excess pressure is destroyed by
internal riser of surge tank
Devices elimination water hammer

29. Water Hammer
Devices elimination water hammer
2. Air valve
Air valve used to release this free air is known as an air release valve. And to admit air
into the system when the internal pressure of the pipeline drops below atmospheric
pressures.
There is three main types of air valve:
• Air release valves
• Air/Vacuum Valves
• Combination Air Valves

30. Water Hammer
Devices elimination water hammer
3. Pressure relief valve
A pressure relief valve is a safety device
designed to protect a vessel or network from
pressure during an event of overpressure.

31. Water Hammer
Devices elimination water hammer
4. Check valve (non-return valve, reflux valve)
It has the capacity to shut the flow off in the event that
the downstream pressure exceeds the upstream
pressure. In this respect, it is used in one direction only
for flow.

32. Water Hammer
Devices elimination water hammer
5. Control valve
A control valve is a mechanism used to control or
manipulate the flow of fluids, it is a critical element of a
control loop and is an example of an aspect of final
control. The Control Valve is the most common final
control component used in today's industry by far

33. Water Hammer
Devices elimination water hammer
Conclusions & recommendations
1. All methods mention can serve in water hammer effect.
2. We cannot use (NRV) only to prevent water hammer effect.
3. No way to use one method to prevent water hammer.
4. Good analysis = Good design = less running cost

34. Water Hammer
Software used to study water hammer
WaterCAD & Hammer are the most programming to design and manage
water systems effectively to reduce disruption risks and energy use. it
helps you successfully plan, design, and operate water distribution
systems:

35. Water Hammer
Water network
Pipe
Length
material
Diameter
Junction
Demand Elevation
Pump
Flow
Elevation
Head
Reservoir
Elevation

36. Water Hammer
Design Criteria of pipeline Networks
• The minimum diameter f pipe = 100 mm
• The velocity = 1-2 m/s
• the minimum residual pressure in the network > .25 m H20
• The valves < 300 mm installed directly on the pipe line (Buried Valves inside
surface box – gate valve)
• The valves >300 mm installed in valves room (butterfly valves)