| Because of the performance advantages of regenerative pumps in the field of low flowrates and high heads fluid delivery, the regenerative pumps have found wide applications like automotive and aerospace fuel pumping and pharmaceutical industries. The circulation flow inside the regenerative pump makes it capable of developing high pressure. However, the circulation flow induces the extra energy consumption, which makes the pump efficiency is not so high. Besides, similar to other fluid machinery, regenerative pumps have noise and vibration problems induced by pressure fluctuation caused by the fluid-structure interaction between the rotating impeller and stationary stripper. For automotive and aerospace fuel pumping, the low-efficiency and noise and vibration of regenerative flow pumps are the key issues need to be solved. The paper studied the internal flow and pressure fluctuation for performance development and noise and vibration reduction of the regenerative pump applied in automotive pumping system.The steady and unsteady simulation models of a micro axial regenerative pump were studied and verified by experiments. It turned out that the simulation and experiment results had a good agreement, and the difference between the results of numerical simulation and experiments were analyzed. The influence on performance of different fluid and axial position of impeller is analyzed. According to the results, the fluid viscosity had much influence on the hydraulic efficiency. In the same way, the thinner fluid film of inlet side caused by the unbalanced force of fluid made the disk friction loss increase and the efficiency decrease. The influences on pressure fluctuation of different fuel fluid and axial position of impeller were compared. It was found that the fluid characteristics had almost no influence on pressure fluctuation inside of the pump. However, the amplitude of BPF of pump changed if the axial position of the impeller changed. And the fluid-structure interaction of outlet side is stronger than one of inlet side, so it would be helpful if the clearance between outlet stripper and impeller was large.The internal flow and pressure fluctuation were simulated and analyzed in the paper. It was found that there were vertical vortex, radial vortex and axial vortex inside the pump. And because the vertical vortex induced momentum exchanges between fluid inside channels and fluid inside impeller, it was the main reason for pressure rising. According to the analysis of the pressure fluctuation, the amplitudes along the channel were low while the amplitudes near the stripper were high, which proved the main reason of BPF was the fluid-structure interaction.The influence of different cross sections of channels on performance was analyzed, and the results showed that enlarging the channel cross section area of outlet side would make the h-q curve migrate to large flowrate and increase the hydraulic efficiency. The paper put forward the non-uniform cross section channel and the analysis found when the equivalent sections of channels were equal, the non-uniform channel was helpful for decreasing the torque and increasing the efficiency.Uneven circumferential blade spacing was adopted to improve the pressure fluctuation characteristics and the numerical simulation was conducted. The result indicated that the uneven circumferential spacing had little influence on the h-q curve and as the internal flow changed after modification, the hydraulic efficiency would change. And the structure would yield additional frequency in the spectrum compared with even circumferential spacing and reduce the magnitude of the dominant frequency. And the statistical analysis of 60 kinds of uneven spacing was carried out to obtain a reference for multi-blade impeller uneven blade spacing design. The above results can be applied to optimization design of regenerative pumps used in the engine fuel system and provide reference for vibration and noise reduction of other multi-blade fluid machinery. |
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