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CHALLENGES FACED WHEN CHOOSING THE CORRECT PUMP SIZE DUE TO NO FRICTION HEAD LOSS BEEN CALCULATED ON THE RISING MAIN IN THE SYSTEM(SOURCE TO TANK) 2.)NEED FOR CUMULATIVEFRICTION HEADLOSS

Hello Bentley Communities,

I am facing challenges when it comes to choosing the correct pump size for my water system.WaterCad is not able to calculate for me friction head loss in the pipes and I will assume this is because of zero-flow in the pipe, yet I have entered the demand at the end of the pipeline.Can WaterCad be able to calculate head loss due to friction or in other words allows flow in the rising pipeline from the source to a tank on the upstream side of the network? ; as it is possible when designing a rising main from any source to a node located at a higher elevation?Is it because of the tank that the system will not allow any flow?In the case where I replace the tank with a junction node then losses will be calculated in the pipe.

How will I be able to choose the correct pump size for my network since I need to know the total amount of pressure of water needed at the end of the network(which is a function of friction losses)/Is there a way that I can allow friction losses to be calculated without removing "TANK 5"

Please have a look at the attached file.SITIKHO buyofu ANALYSIS.rar

The second question is that I would address the need for Cumulative friction losses along the pipeline.Can you guys please introduce it the pipe flex table?

Parents
  • WaterCAD has all the tools you need for the hydraulic design of your pump and associated piping.  is this a wastewater rising main or a water distribution system? I'll assume for now it is wastewater.

    Lay out the piping.

    Make the wet well a tank element and have the load be a negative demand on the tank. Make the receiving manhole a reservoir  element with the water level the level of the typical depth in the manhole.

    Insert a likely candidate pump(s) in the pump station.

    Right click on the System head curve option on the pump can view the system head curve. This gives you the head you'll need to provide at various flows. If it is very steep, upsize your piping. If it is flat, you can downsize it.

    Now try different pumps. Pick a model and impeller size such that the operating point, desired flow and best efficiency point coincide. If you want to pump 40 L/s, pick a pump with a BEP of 40 and make sure it will operate at 40.

    Next set up an extended period simulation run and adjust the controls so that it will operate as desired.

    The steps are slightly different for a water distribution system primarily in terms of how you handle the suction side piping and the fact that you place demands on the outlet side.

    Best wishes,

Reply
  • WaterCAD has all the tools you need for the hydraulic design of your pump and associated piping.  is this a wastewater rising main or a water distribution system? I'll assume for now it is wastewater.

    Lay out the piping.

    Make the wet well a tank element and have the load be a negative demand on the tank. Make the receiving manhole a reservoir  element with the water level the level of the typical depth in the manhole.

    Insert a likely candidate pump(s) in the pump station.

    Right click on the System head curve option on the pump can view the system head curve. This gives you the head you'll need to provide at various flows. If it is very steep, upsize your piping. If it is flat, you can downsize it.

    Now try different pumps. Pick a model and impeller size such that the operating point, desired flow and best efficiency point coincide. If you want to pump 40 L/s, pick a pump with a BEP of 40 and make sure it will operate at 40.

    Next set up an extended period simulation run and adjust the controls so that it will operate as desired.

    The steps are slightly different for a water distribution system primarily in terms of how you handle the suction side piping and the fact that you place demands on the outlet side.

    Best wishes,

Children