IntroductionHere you find 17 WANDA cases which help to understand the waterhammer phenomena. All cases include a movie. In order to play the movie, you must install the Techsmith ScreenCapture Codec (more information - Download). The examples are also available as Wanda cases - Download 1) Positive pressure wavesDescription: Instantaneous valve closure at the end of a frictionless pipe Phenomenon: Propagation of positive pressure wave download movie ![](/download/attachments/53542947/case01.png?version=1&modificationDate=1251832258000&api=v2)
System data Property | Value |
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Diameter | 500 mm | Length | 10000 m; | Friction | No friction | Wave speed | 1000 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve
- instantaneous closure (within 1 timestep)
![](/download/attachments/53542947/case01a.png?version=1&modificationDate=1251832258000&api=v2) 2) Positive and negative pressure wavesDescription: Instantaneous valve closure in the middle of a frictionless pipe Phenomenon: Propagation of positive and negative pressure wave download movie ![](/download/attachments/53542947/case02.png?version=1&modificationDate=1251832258000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 5000 m; | Friction | No friction | Wave speed | 1000 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve
- instantaneous closure (within 1 timestep)
![](/download/attachments/53542947/case02b.png?version=1&modificationDate=1251832258000&api=v2) 3) Pressure waves and line packingDescription: Instantaneous valve closure at the end of a pipe with friction (line packing) Phenomenon: Propagation of positive pressure wave and line packing download movie ![](/download/attachments/53542947/case03.png?version=1&modificationDate=1251832577000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m; | Friction factor | 0.0222 (k = 1 mm) | Wave speed | 1000 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve
- instantaneous closure (within 1 timestep)
![](/download/attachments/53542947/case03b.png?version=1&modificationDate=1251832577000&api=v2) 4) Effect of surge tower on pressure waves Description: Instantaneous valve closure at the end of a pipe with friction and surge tower as the anti-surge device Phenomenon: Effect of surge tower on pressure waves download movie ![](/download/attachments/53542947/case04.png?version=1&modificationDate=1251832577000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m; | Friction factor | 0.0222 (k = 1 mm) | Wave speed | 1000 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve
- instantaneous closure (within 1 timestep)
Surge tower: - Area = 0.01 m 2 (vertical pipe with 113 mm internal diameter)
5) Propagation and development of negative pressure wave Description: Pump trip with small polar moment of inertia Phenomenon: Propagation and development of negative pressure wave download movie ![](/download/attachments/53542947/case05.png?version=1&modificationDate=1251832968000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m; | Friction factor | 0.0218 (k = 0.25 mm) | Static head | 2.0 m | Wave speed | 1000 m/s | Initial velocity | 0.6 m/s |
Pump data: - Duty point is 100 m3/h at 17 m head
- Polar moment of inertia 0.1 kgm2
![](/download/attachments/53542947/case05b.png?version=1&modificationDate=1251832968000&api=v2) 6) Propagation and development of negative pressure wave 2Description: Pump trip with large polar moment of inertia Phenomenon: Propagation and development of negative pressure wave download movie ![](/download/attachments/53542947/case06.png?version=1&modificationDate=1251832968000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m; | Friction factor | 0.0218 (k = 0.25 mm) | Static head | 2.0 m | Wave speed | 1000 m/s | Initial velocity | 0.6 m/s |
Pump data: - Duty point is 100 m3/h at 17 m head
- Polar moment of inertia 2.0 kgm2
![](/download/attachments/53542947/case06b.png?version=1&modificationDate=1251832998000&api=v2) 7) Effect of surge tower Description: Pump trip with small polar moment of inertia and surge tower as the anti-surge device Phenomenon: Effect of surge tower download movie ![](/download/attachments/53542947/case07.png?version=1&modificationDate=1251834400000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m; | Friction factor | 0.0218 (k = 0.25 mm) | Static head | 2.0 m | Wave speed | 1000 m/s | Initial velocity | 0.6 m/s |
Pump data: - Duty point is 100 m3/h at 17 m head
- Polar moment of inertia 0.1 kgm2
Surge tower: ![](/download/attachments/53542947/case07b.png?version=1&modificationDate=1251834400000&api=v2) 8) Reflections on diameter changesDescription: Two frictionless pipes in series with different diameters; instantaneous valve closure at the end of the system in the pipe with smallest diameter (reflection) Phenomenon: Effect of diameter change on pressure wave - reflection download movie ![](/download/attachments/53542947/case08.png?version=1&modificationDate=1251834424000&api=v2)
System data Property | Value |
---|
Diameter Pipe 1 | 500 mm | Diameter Pipe 2 | 250 mm | Length | 5000 m; | Friction factor | no friction | Wave speed | 1000 m/s | Initial velocity D=250 | 1.0 m/s |
Valve data: - Butterfly valve; instantaneous closure (within 1 timestep)
9) Reflections on diameter changes 2Description: Two frictionless pipes in series with different diameters; instantaneous valve closure at the end of the system in the pipe with largest diameter (reflection) Phenomenon: Effect of diameter change on pressure wave - reflection download movie ![](/download/attachments/53542947/case09.png?version=1&modificationDate=1251834424000&api=v2)
System data Property | Value |
---|
Diameter Pipe 1 | 250 mm | Diameter Pipe 2 | 500 mm | Length | 5000 m; | Friction factor | no friction | Wave speed | 1000 m/s | Initial velocity D=250 | 1.0 m/s |
Valve data: - Butterfly valve; instantaneous closure (within 1 timestep)
10) Changes in wave speed Description: Two frictionless pipes in series with different pressure wave celerity; instantaneous valve closure at the end of the system in the pipe with smallest wave celerity (reflection) Phenomenon: Effect of wave celerity change on pressure wave (e.g. change in pipe material) download movie ![](/download/attachments/53542947/case10.png?version=1&modificationDate=1251834450000&api=v2)
System data Property | Value |
---|
Diameter both pipes | 500 mm | Length | 5000 m; | Friction factor | no friction | Wave speed pipe 1 | 1000 m/s | Wave speed pipe 2 | 200 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve; instantaneous closure (within 1 timestep)
11) Changes in wave speed 2Description: Two frictionless pipes in series with different pressure wave celerity; instantaneous valve closure at the end of the system in the pipe with largest wave celerity (reflection) Phenomenon: Effect of wave celerity change on pressure wave (e.g. change in pipe material) download movie ![](/download/attachments/53542947/case11.png?version=1&modificationDate=1251836140000&api=v2)
System data Property | Value |
---|
Diameter both pipes | 500 mm | Length | 5000 m; | Friction factor | no friction | Wave speed pipe 1 | 200 m/s | Wave speed pipe 2 | 1000 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve; instantaneous closure (within 1 timestep)
12) Reflections on branches and closed end Description: Branched system with closed end; valve closure in main line Phenomenon: Reflections on branches and closed end download movie ![](/download/attachments/53542947/case12.png?version=1&modificationDate=1251836140000&api=v2)
System data Property | Value |
---|
Diameter pipe 1 | 500 mm | Diameter pipe 2 | 500 mm | Diameter pipe 3 | 250 mm | Length Pipe 1 | 5000 m; | Length Pipe 2 | 5000 m; | Length Pipe 3 | 3000 m; | Friction factor | no friction | Wave speed | 1000 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve; instantaneous closure (within 1 timestep)
![](/download/attachments/53542947/case12b.png?version=1&modificationDate=1251836160000&api=v2) 13) Cavitation and cavitation collapseDescription: Concentrated cavity in high point after pump trip Phenomenon: Effect of cavitation and cavity implosion on system pressures download movie ![](/download/attachments/53542947/case13.png?version=1&modificationDate=1251836160000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m; | Friction factor | 0.0218 (k = 0.25 mm) | Static Head | 2.0 m | Wave speed | 1000 m/s | Initial velocity | 1.0 m/s |
pipeline profile: ![](/download/attachments/53542947/case13a.PNG?version=1&modificationDate=1251836160000&api=v2) Pump data: - Duty point is 100 m3/h at 17 m head
- Polar moment of inertia 0.5 kgm2
![](/download/attachments/53542947/case13c.PNG?version=1&modificationDate=1251836179000&api=v2) 14) Cavitation and cavitation collapse 2Description: Extended cavity in horizontal pipeline after pump trip Phenomenon: Effect of cavity and cavity implosion on system pressures download movie ![](/download/attachments/53542947/case14.png?version=1&modificationDate=1251836179000&api=v2)
System data Property | Value |
---|
Diameter | 250 mm | Length | 10000 m; | Friction factor | 0.0218 (k = 0.25 mm) | Static Head | 2.0 m | Wave speed | 1000 m/s | Initial velocity | 0.6 m/s |
pipeline profile: ![](/download/attachments/53542947/case14a.png?version=1&modificationDate=1251836179000&api=v2) Pump data: - Duty point is 100 m3/h at 17 m head
- Polar moment of inertia 0.1 kgm2
![](/download/attachments/53542947/case14c.png?version=1&modificationDate=1251836201000&api=v2) 15) Propagation of pressure waves; development of flow velocityDescription: Instantaneous valve opening at the end of a pipe with friction Phenomenon: Propagation of pressure waves; development of pipe velocity download movie ![](/download/attachments/53542947/case15.png?version=1&modificationDate=1251836201000&api=v2)
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m; | Friction factor | no friction | Wave speed | 1000 m/s | Initial velocity | 0 m/s |
Valve data: - Butterfly valve; instantaneous opening (within 1 timestep)
![](/download/attachments/53542947/case15b.png?version=1&modificationDate=1251836201000&api=v2) 16) Rigid column method limitationsDescription: Comparison of rigid column approximation and water hammer equations Phenomenon: Maximum pressure is significantly underestimated by rigid column approximation if friction head is small download movie Image Added
System data Property | Value |
---|
Diameter | 200 mm | Length | 900 m; | Wave speed | 900 m/s | Initial velocity | 3.0 m/s |
Image Added 17) Description: Linear and twostage valve closure at the end of a pipe with friction Phenomenon: Effective valve closure time download movie Image Added
System data Property | Value |
---|
Diameter | 500 mm | Length | 10000 m | Friction Factor λ | 0,0154 (wall roughness k = 1 mm) | Wave speed | 1000 m/s | Initial velocity | 1.0 m/s |
Valve data: - Butterfly valve; linear and two-stage valve closure in 5 pipe periods
Image Added
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