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Pump Not Delivering the Designed Flow in WaterGEMS

I am having a pump at the downstream of the reservoir and it is supplying to the two tanks. 

The problem is, I have set 1 point pump definitions with the design flow of 7.75 ML and the pump is delivering just 7.63 ML. I am unable to find out why there is a difference of .12 ML in this case. 

Also, does initial level of tanks play any role in this?

Parents
  • Hello Chetan, 

    When sufficient head is not available pump will not work at designed point, please check if there is huge headloss through pipes or valves in the model. 

    Initial level of tank defines the hydraulic grade line of that pressure zone / area since it is a hydraulic boundary. If you reduce or increase the initial level of tank you will see changes in pressure / HGL results. 

    If this does not help then you can upload model files for our review. 

    Sharing model files.

    Regards,

    Sushma Choure

    Bentley Technical Suppport

Reply
  • Hello Chetan, 

    When sufficient head is not available pump will not work at designed point, please check if there is huge headloss through pipes or valves in the model. 

    Initial level of tank defines the hydraulic grade line of that pressure zone / area since it is a hydraulic boundary. If you reduce or increase the initial level of tank you will see changes in pressure / HGL results. 

    If this does not help then you can upload model files for our review. 

    Sharing model files.

    Regards,

    Sushma Choure

    Bentley Technical Suppport

Children
  • There is no guarantee that a centrifugal pump will pump at it's nominal design flow. If the pipe is a little rough, a valve is partly open, a tank water level is higher than assumed, the flow will decrease. Over the course of a day, as tank water levels go up and down, the pump discharge will vary.

    Remember also that a one point pump curve is an approximation. If you are concerned about accuracy of 0.12 ML (I assume ML/day), then you need the exact pump curve for that pump.