离心泵叶轮内旋转流场激光测量的研究

采用双焦激光流速仪对离心泵叶轮内旋转流场和叶轮出口附近的泵涡壳流速场，选择３个不同方位的窗口进行了测量。所测量的３种不同运行工况，其流量分别为设计流量的１．０，０．７０和０．３８。不同窗口测得的两叶片间流道的流速分布表明，即使在设计工况下，整个叶轮各叶片间的流速分布也不是对称的。叶轮出口处的液流角从叶片吸入侧向叶片压力侧增大，叶片吸入侧出现脱流。这在非设计工况尤其明显，并同时产生二次流。在流量为０．３８设计流量时，二次流较强。液流相对运动的主流从在叶片进口处的吸入侧转移到叶片出口处的压力侧。

STUDY ON LASER VELOCIMETER MEASUREMENTS OFROTATIONAL FLOW FIELD IN A CENTRIFUGAL PUMP

A laser two focus velocimeter was applied to the measurements of flow field in unshrouded im-peller of a centrifugal pump and its volute near the exit of the impeller.Three windows were selected for themeasurements.Three operation points of the pump were taken during the measuring.The ratios(Q/Q)offlow rate to the design one are 1.0,0.70 and 0.38 respectively. The velocity distributions inblade-to-blade passages obtained at different windows give the evidence that the velocity distributions areasymmetric even under the design operation point.The flow angle at exit of impeller increases from the suc-tion side towards the pressure side of the blade ,and a seperation flow was found at suction side especially atoff-design points when the secondary flow occured.The secondary flow became stronger at operation pointof Q/Q=0.38.The main flow of relative motion sifted from the suction side to the pressure side.