I am trying to model a tank with a control valve at the inlet and a pump supplying water into the tank. The control valve is being used to control the flow into the tank. A level transmitter is placed at top of the tank. As the level in the tank increases the control valve gradually closes and vice versa. Moreover a pressure transmitter is mounted on the pipe line prior to the control valve. This pressure transmitter will control the pump speed (VSP) with respect to pipeline pressure. So as the level in the tank increases, the control valve will gradually close, the pressure in the pipeline will increase and the speed of pump impeller will decrease.
How can I set up the controls for VSP and FCV to simulate such a scenario in WaterGems.
Thanks.
Hello Phanindra,
If you want to model the control valve at the tank, you could model a separate inlet valve for the tank, with "Has separate Inlet?" to TRUE and specify the inlet valve there. Since you will be using throttling inlet, the hydraulic time step should be small to capture the throttling behavior.
Instead of modeling VSP here, you could model a pump with controls based on pressure since you mentioned -
pipe line pressure goes up and the pump slows down.
Regards,
Sushma Choure
Bentley Technical Suppport
Just a few things to add to Sushma's response:
1) See more about the tank inlet valve in this article: Modeling top fill tanks and throttling inlet valves
2) You could try setting the pump as a VSP with Target head as the type and set the control node to a junction just before the tank. If convergence issues are seen, try Sushma's suggested approach.
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Answer Verified By: Phanindra Talpade
Hello Sushma,
Thanks a lot for your answer. Can you please elaborate a bit regarding the second part of your answer where you asked me to set up controls based on pipeline pressure. How to do that without considering a VSP and slow down a normal pump based on pipeline pressure?
I''ll be really thankful if you can explain me this in a bit more detail.
Hello Jesse,
Thanks a lot for your reply and providing the link to the article.
You could setup the controls for pump based on pressure in the system. First select junction in the model based on which the pumps will operate. Example is shown below.
IF J-1390 Pressure < 105.0 psi THEN PMP-560 Pump Status = OnIF J-1390 Pressure >= 110.0 psi THEN PMP-560 Pump Status = Off
Or you could model by setting the pump as a VSP with Target head as the type and set the control node to a junction just before the tank, as suggested by Jesse, whichever works for you.