Numerical Study Of Cavitation Flow Characteristics In A High Speed Micro-centrifugal Pump

Traditional low specific speed centrifugal pump energy conversion efficiency is generally low. Pump speed and miniaturization will be an effective way to improve the operating efficiency of the pump under certain conditions of flow and head. With the advances in manufacturing technology, problems of reducing the efficiency can be solved well. However, Traditional high speed centrifugal pumps and pump miniaturization requires better operational reliability of the pump and anti-cavitation ability.In order to understand the phenomenon of cavitation in high speed micro-centrifugal pump, micro-speed centrifugal pumps will be the research subjects in this paper. Cavitation distribution of high speed micro-centrifugal pump under different cavitation number can be acquired by CFX, and impeller blades doing role-conversion function and fluid flow by cavitation are analyzed. The influence of cavitation flow pressure pulsation time domain and frequency domain characteristics are studied by calculation unsteady pressure field of the blade surface and the flow passage of volute.The results indicate that numerical simulation method used in this paper was able to accurately predict the flow of high speed micro-centrifugal pump cavitation within. With the gradual decrease of cavitation numbers, centrifugal pumps anti-cavitation performance is weakened with the increase of flow coefficient within a certain range. The suction side of the blade appears low flow region and the secondary reflux flow, at the same time the local high speed area extend to the flow passage at the trailing edge blade side. Cavitation flow mainly reduced the first half of table load on balde, oppositly blade on the second half of the load size increases. In the cavitation with noncavitation conditions, blade surface and volute pressure pulsation main frequency respectively represent the rotation frequency of the impeller and blade passing frequency or its multiple. When the critical cavitation occurs in the pump, the cavitation blade surface of pressure pulsation amplitude is worth to weaken or even drop to zero, but the amplitude inside the volute are higher than the noncavitation. Finally, sections under different time of vortex in intensity and position changes,which are main factors that cause the volute pressure pulsation amplitude value enhancement.