叶轮叶顶厚度对喷水推进轴流泵空化性能的影响研究

The effect of tip thickness of blade on cavitation performance of waterjet axial flow pump

采用三维雷诺平均N-S方程和标准k-ε湍流模型对不同叶轮叶顶厚度参数的喷水推进轴流泵流场和性能进行数值仿真。结果表明:叶顶最大厚度对喷水推进泵的空化特性产生一定影响,当叶顶最大厚度增加时,在小流量工况,其水力效率上升;当流量超过444 kg/s,特别是超过额定流量时,其水力效率反而下降,且在相同的流量下,最高效率点降低。随叶顶最大厚度的增加,喷泵扬程减小,抗空化性能下降,汽蚀比转速减小。因此,本文选择的叶顶最大厚度为3 mm。选择合理叶顶最大厚度,可有效提高抗汽蚀特性,避免发生局部空化。

Three dimensional Reynolds averaged N-S equation and standard k-ε turbulence model were used to simulate the flow field and performance of waterjet axial flow pump with different tip thickness parameters of the rotor. The results show that the maximum thickness of the blade tip has a certain influence on the cavitation characteristics of the waterjet pump. When the maximum thickness of the tip increases, the hydraulic efficiency increases under the condition of small flow rate. On the contrary, when the flow rate exceeds 444 kg/s, especially the rated flow rate, the hydraulic efficiency decreases, and the maximum efficiency point decreases under the same flow rate. With the increase of the maximum thickness of the blade tip, the head of the pump decreases, cavitation resistance decreases, and cavitation specific speed decreases. Therefore, the maximum thickness of blade tip chosen in this paper is 3 mm. the cavitation performance can be improved effectively and the local cavitation can be avoided by selecting the proper tip maximum thickness of blade.