利用LDV测量离心蜗壳流道内速度场的校核

Verifying the accuracy of LDV used in measuring velocity fields of the centrifugal volute.

介绍了利用激光多普勒测速仪 (LDV)测量离心泵蜗壳流道内部速度场时的速度与流量两种校核方法。说明当蜗壳内的液流速度较高时 ,测量结果较精确 ;当蜗壳内的液流速度较低时 ,测量结果相对误差较大。为此 ,在选择示踪粒子时 ,应尽量减小示踪粒子的直径 ,并使其密度与待测液体密度相当。提出了先采用速度校核法初步确定流道内的速度 ,再选定相应速度下的滤波值与频移值范围 ,最后利用LDV精确测量离心蜗壳流道的内部速度场的测试方法。

Two kinds of methods for verifying the precision of LDV when used in measuring velocity fields of the centrifugal volute are introduced. When the flow rate of the liquid in the volute is fairly high, the values measured are relatively precise; while the flow rate is rather low, the values measured have large relative errors. Therefore the tracer ions with reasonable size and density should be selected. The authors put forward a precise method for measuring the internal velocity fields of the centrifugal volute, i.e. determining the velocity in the volute by the velocity verifying method first, deciding then the range of filtration and the frequency shift magnitude at the corresponding velocity, and measuring the velocity fields by LDV at the end.