1 Reply Latest reply on Apr 3, 2014 8:42 PM by Jared Conway

    Negative torque

    Enda Roche

      Hi guys,

      I'm currently running a flow simulation on a Wells turbine and am running into a little difficulty. The Wells turbine is enclosed in a 0.6m pipe, with a tip clearance of 1mm between blade and pipe. I am running tests with a speed range of 1000-2000 rpm. I have enclosed a rotating region around the blades of the Wells turbine. The rotating region covers exactly the width of the blade. I have set an inlet flow of 5.98m/s and static pressure at the outlet. I set a surface goal for torque on the 6 blades of the Wells turbine. When I run the study I am getting negative torque in my results. I have the rotating region rotating in the right direction aswell. The pressure drops across the turbine steadily increase with speed, but my torque increases in the negative direction.

      This is giving me negative efficiency when I do calculations. Any ideas where I'm going wrong?

      Any advice is greatly appreciated.

       

      Regards,

        • Re: Negative torque
          Jared Conway

          if your rotating region is just barely past the tip of the blades, it sounds like you have not reviewed the recommendations for rotation regions. i would recommend starting there and also looking at the technical reference, solving engineering problems document, the help and the solidworks kb. rotating regions are difficult.

           

          http://ec.europa.eu/research/energy/nn/nn_rt/nn_rt_oes/images/wells_blade_1_1424.jpg

           

          is i assume what you're working with. this looks like it may be outside the scope of what is recommended for rotating regions. you may want to check with your reseller on whether this is a good application for rotating regions. if a customer brought this type of project to me to solve from a consulting perspective, we would check with the developers first as the flow simulation rotating region method works for cases that are like pumps/impellers.