I have placed a FCV before pumpins station for flow control. I created a valve setting pattern same as the node on the downstream side to analyse it in EPS. but it is showing following errors:
1. FCV cannot deliver flow.
2. Maximum trials exceeded.System may be unstable.
3. Negative pressure at FCV.
4. Negative pressure at downstream junction.
5. Negative pressure at downstream pump
How can i fix these issues?
Hello Rahul,
See my responses below;
rahul dixit said:1. FCV cannot deliver flow
This means that the flow through the valve is less than the setting that you entered thus causing the valve to remain fully open i.e. inactive. See the below article on this for more details on resolution of this error;
What is the meaning of the notification "Valve cannot deliver flow", with regards to a Flow Control Valve (FCV)?
rahul dixit said:2. Maximum trials exceeded.System may be unstable
This message means that the maximum number of trials specified in the solver have exceeded and a valid solution is not found. You can increase the number of trials by going to Analysis > Calculation Options. Under the "Steady State/EPS Solver" section, double-click on the active calculation option to view the properties. Find the property field "Trials" and set this to a higher value, such as 400. See if this helps in resolving this notification. More details on this can be found in the below article;
Troubleshooting the Network Unbalanced or Cannot solve network hydraulic equations user notification
rahul dixit said:3. Negative pressure at FCV. 4. Negative pressure at downstream junction. 5. Negative pressure at downstream pump
This could be related to the FCV operation. Check to see if the FCV is limiting flow downstream which might be causing downstream elements demands not to be fulfilled or restricting flow to a downstream pump. See the article below for more details on this;
Problems when using a flow control valve (FCV) downstream of a pump
Let me know if this helps.
Regards,
Yashodhan Joshi
Bentley Technical Support