诱导轮偏转角对离心泵叶轮空化性能的影响

为了阐明诱导轮偏转角对离心泵叶轮空化性能的影响,改善离心泵的空化性能,找到最佳周向位置,基于均相流假设,采用IDM空化模型与RNG k-ε湍流模型,先选取诱导轮偏转角分别为0°,10°,20°,30°,40°,50°共6种方案,对离心泵外特性及诱导轮和叶轮空化性能进行数值模拟和试验对比,得到不同方案下离心泵的性能数据.计算得到的NPSHR曲线与试验数据吻合较好,验证了计算方法的准确性;基于数值模拟结果,分析了不同偏转角下诱导轮与叶轮内气泡分布规律,发现不同偏转角下诱导轮和叶轮内空化发展过程及气泡发展规律基本相同,但偏转角为10°时气泡发展速度较慢、各空化阶段分布面积较小,进一步选择5°和15°偏转角进行计算分析,得到更精确的结论,即诱导轮偏转角为5°时离心泵的综合水力性能最优.

Effect of inducer deflection angle on impeller cavitation performance in centrifugal pump

In order to clarify the effect of inducer deflection on cavitation performance of centrifugal pump impeller, improve centrifugal pump cavitation performance, and get the best circumferential position, based on the homogeneous flow assumption, the IDM cavitation model and the RNG k-ε turbulence model were adopteed and five projects which deflections are 0°,10°,20°,30°,40° and 50° were selected,to compare numerical simulation values and experimental values of pump′s external characteristics and cavitation performances of inducer and impeller. The centrifugal pump characteristic performance data of different projects were obtained. Calculated NPSHR curves match well with experimental ones, which can verify the accuracy of the calculation methods. Based on numerical simulation results, vapor volume fraction distributions within inducer and impeller blades under various conditions were analyzed.It was found that cavitation bubbles′ development processes and rates of 10° and 20°positions are basically the same, but the cavitation rate and vapor volume fraction distribution areas are smaller when the deflection is 10°, therefore two deflectians of 5° and 15° were further selected to do simulation analysis to get more accurate results, i.e. the pump′s overall hydraulic characteristic is the best when the deflection is 5°.