Cavitation characteristics of multiphase pump at low flow rate
LIU Xiaobing1,2, HU Quanyou1, SHI Guangtai1,2, ZHAO Qin1,2
1.School of Energy and Power Engineering, Xihua University, Chengdu, Sichuan 610039, China; 2.Key Laboratory of Fluid and Power Machinery, Ministry of Education, Xihua University, Chengdu, Sichuan 610039, China
Abstract：The hydraulic performance of multiphase pump is poor at low flow rate. To improve its performance, the cavitating flow field in a multiphase pump was simulated numerically under low flow rate conditions by using the homogenous multiphase flow model, Rayleigh-Plesset equation and standard k-ε two-equation turbulence model. The transport properties of the pump were analyzed under several typical cavitation conditions and the distribution features of cavitation bubbles in the impeller were clarified. The head and efficiency curves of the pump were predicated and compared with the experimental results, validating the reliability of simulation results to some extent. The results showed that the flow around the blade leading edge and the rotor-stator interaction had a great influence on flow separation in the impeller at a low flow rate, and the low pressure zone formed with vortices could aggravate inlet cavitation and reduce the performance of the pump. Cavitation was generated at the blade leading edge near the blade mid-span at first. Then the cavitation got worse on the blade suction side near the leading edge, the closer to the hub, the worse the cavitation. The cavity on the blade suction side could even block the impeller flow passages and intensify the phase separation of flow in the impeller. These results provide a theoretical basis for design optimization, performance improvement and further experimental study on multiphase pumps.
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