i'm runing a model of pump station

[Ouahmed]

i'm runing a model of pump station and i have simulated, using AFT impulse as software, the shut off of pump and the surge caused by it, so i have surge around 300 bar in upstream and downstream pipes (DN400 and DN500). i don't know if surge can reach such pressure !!

I feel like i'm missing something!

 

[MFJewell]

Is this modelled as the pump (or a discharge valve) instantaneously going shut? I would suspect it could cause water hammer which may be what AFT is showing you in the form of the pressure spike. Probably would be useful to give more details on the system such as sketch of piping layout, working fluid, etc.

 

[BigInch]

High. You should probaby not reach 300 barg surge unless you started with something at least around 200 barg normal discharge pressure. What's your velocity?

Technology is stealing American jobs. Stop H1-Bs for robots.

 

[Ouahmed]

Thx for yours replies
Hi BigInch ;
the velocity equal for 1.4 m/s. the steady state pressure is 17 bar.

hi MFJewell ;
i'm working on pump instantaneously going shut in water pump station,the distance between station and discharge tank is 10 km

 

[LittleInch]

An OOM error somewhere. I would hardly expect 30 bar from that description.

It might be thinking that you're creating a vacuum which then collapses as flow reverses D/S the pump.

This can create a large pressure, but it's not real for your situation. Try and put in a slow down mode for the pump, even of 3-5 seconds might be enough.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Ouahmed]

hi LittleInch

thx for your replie,i will try it, i want to ask about the difference between transient model of pumps:
-No transient-Four quadrant
-Trip with Inetia and no back flow or reverse speed
-Trip with inertia- Four quadrant
-Start up with Inetia and no back flow or reverse speed
-Start up with inertia- Four quadrant
-start up- Four quadrant known speed

 

[AWloo]

You can find more information within the userguide in AFT Impulse by pressing F1. Have a look through the user documentation to understand these in more detail. The transient model that you chose depends on what you are trying to determine.

In this case you are looking at what happens when you shut down a pump so it would be the Trip with inertia. Then you need to determine if backflow can happen and that will help you decide if you are using four quadrant or not.

 

[Ouahmed]

Hi AWloo ;

Thx for your help

 

[BigInch]

At that velocity it would be unlikely to generate more than 1/2 the normal pressure, 25 bar or so.

Technology is stealing American jobs. Stop H1-Bs for robots.