离心泵启动过程瞬态特性的试验

为进一步研究离心泵启动过程的瞬态特性,建立了离心泵瞬态性能测试系统.在球阀全开、半开和全闭3种条件下,对离心泵的启动过程进行试验.在采集瞬态性能曲线的同时,应用粒子成像测速技术对离心泵测试截面的二维瞬态流速进行了拍摄,并分析了瞬时外特性与内部流动演化关系和产生试验误差的原因.结果表明,离心泵启动过程中内部流动演化呈现强烈的瞬态特性.开阀启动过程扬程和功率随转速快速上升,瞬时流量表现出三次曲线的增长特性;阀门全关启动的瞬时功率冲击达到稳态条件下的1.5倍,内部瞬态流动显示该冲击是由流体间相互掺混和涡能量的传递所引起的.产生气泡和低的拍摄频率是引起PIV测试误差的主要原因.

Experiment on instantaneous characteristics in centrifugal pump during startup period

To further research instantaneous characteristics in centrifugal pump during startup period,a centrifugal pump instantaneous performance test system was established.Experiments on the startup process of a centrifugal pump with ball valve fully opened,semi-opened and fully closed were carried out,respectively.At the same time of testing the instantaneous explicit performances,2D instantaneous flow field on the pump test section were captured with particle image velocimetry（PIV） technique.The reasons causing test error and relationships between external characteristics and internal flow evolutions were discussed.The results show that the internal flow of the centrifugal pump appears intense instantaneous characteristics during startup period.For startup with valve fully opened,both the instantaneous head and power increase rapidly with rotational speed increasing,and the instantaneous flow rate shows cubic trait characteristic.For startup with valve fully closed,the maximum power shock reaches 1.5 times of the steady state.The internal instantaneous flow indicates the shock is caused by fluid mixing and mutually transfer of vortex energy.The bubble and low shooting frequency are the main reasons for the PIV test errors.