I agree with Mohamad.
The problem is that you are pumping into a dead end system with fixed demands. If the flow is fixed, you can't get a curve. In order to get this to work, you need to have storage on both sides of the pump or model the demands as emitters or pressure dependent.
I've attached a journal paper we did a few years ago explaining this.
Dear All
Thanks A lot for your responses i figured out the problem as both of you said it is due to dead end system. and i should use pressure dependent demand functions.
Thanks alot
Dear Tom;
Good Evening, I tried to model the demands as emitters or pressure dependent, but i could not and the problem for the system head curve still. so please if you can explain on the attached model how to model the demands emitters or pressure dependent.
Thanks in Advance
Eng Sayed Ali
Here is good topics will help you:
Regards........Mohamad
communities.bentley.com/.../2671.aspx
Dear Mohamad
Thanks for this information. i tried to model the demand at juctions using pressure dependent demand function but this results as not as expected. i attached again the watergems model and excel spreadsheet for the expected system head curve. so please if you specify what to de exactly in the model to get the same result as per attached excel sheet, this will be so kind of you. please not that the minimum required residual pressure 3 bar at least.
Regards
Sayed Ali