Abstract: Advanced high speed MEMRECAM Ci 3 system is employed to make a experimental observation & study on moving condition & trajectories of solid particles, the stable & accumulating movement character of air phase, mechanism of performance abrupt by air-admission. Conclusions are drawn on the general movement character of air & solid phase and preliminary analysis has been carried out on its’ moving mechanism. Mainly that solid particles move in a generally dispersed and a little trended way with relation to its’ shape & density; the behavior of air phase is relevant to inlet air fraction & the operating of the impeller, generally air phase separates and aggravates firstly on the outer side of the impeller, then accumulates and emerges hollow space in the center. When losing activity by air pocket, pump shakes fairly violently and may cause badly damage. All the results will be beneficial for using & developing centrifugal pump.

Key words: Air phase, Centrifugal pump, Moving character, Solid particles