|
|
|
| Effects of offset blade on the pressure pulsation and wake structures in a centrifugal pump |
| GAO Bo*, ZHOU Zhiwei, NI Dan, ZHANG Ning, GU Jiarong |
| School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China |
|
|
|
|
Abstract Wake structure of the impeller blade is an important factor which can induce strong pressure pulsation in a centrifugal pump. A low specific speed centrifugal pump was chosen as the research object. The unsteady calculation of the flow flied was carried out by DDES(delayed detached eddy simulation)method in the pump. The pressure pulsation spectrum characteristics and wake vortex structures of three impeller types, i.e., the ordinary impeller, airfoil blade impeller and offset blade impeller, were compared in detail. It is shown that, the pump head is significantly increased with the offset blade impeller. The efficiency near the design working condition is higher than the other two impeller types, and the high efficiency area is wider. Compared with the ordinary impeller, the pressure pulsation amplitude at the fBPF solution is greatly reduced with the offset blade, especially in the vicinity of the tongue. The fBPF amplitude drops by 43%, and the pulsation energy in the low frequency range is also suppressed. Due to the effect by the interference of the offset blade wake, the high vorticity area of the impeller blade wake is significantly reduced, and the average vorticity intensity is weakened, which is the main reason for the decreasing of the pressure pulsation energy. Therefore, the offset blade design can effectively suppress the impeller blade wake vortex and reduce the pump pressure pulsation energy.
|
|
Received: 09 September 2020
|
|
|
|
|
|
|
