%A WU Xian-Fang, LIU Hou-Lin, WANG Kai, TAN Ming-Gao, YANG Dong-Sheng %T 3D PIV measurement of flow in doubleª²channel pump under overall operating conditions %0 Journal Article %D 2012 %J Journal of Drainage and Irrigation Machinery Engin %R 10.3969/j.issn.1674-8530.2012.06.010 %P 665-669 %V 30 %N 6 %U {http://zzs.ujs.edu.cn/pgjx/CN/abstract/article_468.shtml} %8 2012-11-30 %X The inner flow characteristics in a doubleª²channel pump were measured under eight flow rates with a particle image velocimetry (PIV). To guarantee the accuracy of three dimensional PIV measurements, a few key techniques, such as the optical fiberª²based external trigger synchronization system and three dimensional equivalent calibration methods, were applied in the measurements. A Visual C++2005 code was composed to obtain the relative velocity components from the absolute ones measured according to the velocity triangle. The results showed that one large scale doesn¬ðt appear in a flow passage of the impeller until the flow rate as low as 0ª±4 time the design flow rate Qd.. Moreover, this vortex gets more evident with decreasing flow rate. As flow rate decreases, the absolute velocity in the volute diffuser is decreased as well. A vortex doesn¬ðt occur there until the flow rate is reduced to 0ª±2Qd. The absolute velocity gets maximum values at the flow rate of 0ª±2Qd. There exist dominated largeª²scale vortices in the impeller and volute at the shutª²off condition, suggesting the poorest flow condition has emerged there.