Numerical prediction of clock effect of diffuser in volute on blade loading in centrifugal pump
PENG Xiaona，ZHU Xiangyuan，LI Guojun，JIANG Wei
Key Laboratory of Thermal Fluid Science and Engineering of MOE, Xi′an Jiaotong University, Xi′an, Shaanxi 710049, China; College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
Abstract Unsteady numerical simulations of internal flow field in a centrifugal pump in different clock positions of a diffuser related to the volute tongue were carried out by using structured-grid and the SST turbulence model and influence of clock effect on blade loadings in the impeller and radial diffuser was studied. The results show that with increasing flow rate the pressure loading on impeller blades and diffuser vanes is decreased gradually, indicating gradually reduced work done by the impeller. The pressure on the diffuser vane suction side is higher than on the pressure side due to influence of the volute tongue. When the tongue is located in the middle of two diffuser vanes, the pressure side of impeller blades is subject to a larger loading, suggesting the impeller has a better capability of working. When a diffuser vane is positioned closely to the volute tongue gradually, the region of the loading on the vane suction side being higher than on the pressure side in the diffuser is extended into the diffusion section from the spiral section. The pressure pulsation intensity in the spiral section increases gradually, however, the intensity in diffusion section is decreased steadily. This phenomenon indicates that the pressure pulsation intensity in the diffusion section is affected mainly by the volute tongue, but the intensity in the spiral section is done basically by the leading edge of diffuser vane.
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