10 Replies Latest reply on May 19, 2010 5:38 AM by 1-P1FEF6

    To obtain pump characteristics curve....

      Dear Friends,

       

                     We are carrying out analysis ( flow simulation) for a pump. We wanted to obtain the pump characteristic curve for the model.

       

      We gave the following inputs for trails :

       

      a. Input volume flow rate ( m3/s).

      b. static pressure at outlet.

       

      Besides, we tried environmental pressure at the outlet instead of static pressure.

       

      On both these cases, we found that the pump curve, particularly head is climbing up against the discharge Q.

       

      Any suggestions? What should be the ideal boundary conditions or the factors that should be given as input to achieve required output.

       

      Thank you for your valuable suggestions.

       

      Sincerely,

      Vipin kumar & Panneer selvam.

        • Re: To obtain pump characteristics curve....
          Roland Schwarz

          What type of pump?

           

          Can you post a picture of the resulting curve?

            • Re: To obtain pump characteristics curve....

              Hi,

               

              It is a centrifugal pump type with head decreasing as the flow rate increases

               

              We donot know what BC's to be given so that we can obtain the flow rate and the total pressure at the pump exit.

               

              Thanks

              VK&PS

                • Re: To obtain pump characteristics curve....
                  Deepak Gupta

                  You can always measure the pressure and flow rate at outlet. And everything will depends on the inputs you give.

                   

                  Just under results, RMB on surface parameter and select insert. Then select the face/surface at outlet and get the parameters like pressure, temperature, flow rate, etc.

                  • Re: To obtain pump characteristics curve....
                    Roland Schwarz

                    Keep an eye on the pump speed, as well.  You want to take your measurements at a constant RPM, and control flow with a throttle valve on the outlet.

                     

                    As far as volume, input = ouput (assuming no leakage), since most liquids are essentially incompressible.  Make sure your volume measurement instruments are properly set up (i.e. venturi not too close to a bend or valve, typically at least 10x pipe diameter from nearest obstruction).

                     

                    The pressure to measure is the differential pressure between inlet and outlet.  You should record both inlet and outlet pressures or have a dP gage set up.Make sure inlet pressure is high enough to avoid cavitation.

                     

                    If you are getting good data, 4 or 5 data points between full open and full shut should be sufficient.  I would be more comfortable with 10 to 12.

                • Re: To obtain pump characteristics curve....
                  Rich Bayless

                  Hello,

                   

                  It sounds like you set up the geometry of the pump housing and then applied a range of inlet flow rates.  Flow sim would then compute the back pressure at each flow rate, giving a curve where the pressure drop rises with rising flow rate.

                   

                  What I think you are asking, is how to use Flow sim to simulate the pumping action of the rotating impeller?

                   

                  Have you studied the 'Rotating Impeller' chapter in the Flow sim tutorial document?

                   

                  Cheers,  Rich.

                    • Re: To obtain pump characteristics curve....

                      Hi,

                       

                      Actually I have developed a new impeller & diffuser....to say a pump.

                       

                      Now I donot know what is the pump characteristics Q Vs H.

                       

                      To obtain that characteristics what would be the Boundary condition that I have to specify.

                      Initially I gave the above said Boundary condition but the pump characteristic (Q Vs H) is an increasing curve...but it should be a dropping curve.

                       

                      I am getting the dropping curve from my experimental results.....so now to establish a standard procedure in Flow Simulation what is the Boundary condition that is to be specified......if anyone has tried out before....please help me

                       

                       

                      Thanks,

                       

                      VK&PS

                    • Re: To obtain pump characteristics curve....
                      Radoslaw Koneczny

                      Hi,

                       

                        I think that you shall try tool called "Parametric study" to obtain pump characteristic.

                      It is located in FlowSimulation-> Tools-> Parametric study and give us possibility to compare flow characteristics depending on change in General Settings parameter (angular velocity in this case).

                      Set inlet and outlet as pressure openings, and compare flow characteristics changes by angular velocity change through Parametric study definition.

                       

                      Regards
                      RadeK

                        • Re: To obtain pump characteristics curve....
                          Ameer Chilakala

                          Hi VK,

                           

                          My first question is did u know how to solve the centrifugal pump simulation in the flow simulation? Did u used rotating region option in your problem i.e. for specifying the impeller rotation value i.e. RPM.

                           

                          Go through the online tutorials reg impeller problem in the flow simulation.

                           

                          you metioned that u r having experimental data with you, so take one of volume flow rate conditions or inlet or out let pressure conditions and solve the problem i.e. specify the inlet volume flow rate and out let conditions is the environment/static pressure.

                           

                          if you want apply the varying input volume flow rate condition means, use time dependent option in the general settings and use dependency option i.e. specify the volume flow rate W.R.T to the time.

                           

                          define the goals i.e. pressure head loss i.e. differences of inlet/oulet pressure conditions, volume flow rate conditions etc.

                           

                          form the goals plot data you can manuallly plot the discharge vs head varying graphs.

                           

                          kindly let me know if i am wrong.

                           

                          regards,

                          ameer.C

                            • Re: To obtain pump characteristics curve....

                              Thanks Ameer,

                               

                              This is what I wanted...... the Boundary conditions (BC) that are to be specified .

                               

                              In this case I have experimental results but in cases where we develop certain theoretical models

                              and want to get the pump characteristics curve we should know what BC has to be given to obtain the correct result.

                               

                              Thanks anyway.

                               

                              Presently I have given Inlet velocity and Static Pressure (Environmental)outlet - First Step => Output Goal is Flow rate

                               

                              In second step I apply Static Pressure (Environmental) at inlet and get the total pressure difference between outlet and inlet => head.

                               

                              Is this a right procedure.

                               

                              VK