3D-PIV Measurements In Clearance Between The Impeller And The Diffuser Of An Axial Flow Pump

Flow pattern, in clearance between the impeller and the post guide vanes in an axial flow pump, has an obvious influence on the performance of pump. The dissertation used the testing technique of 3D-Laser to study the distributing rule of the flow velocity, and the relation between it and the performance of pump. It is helpful for the validation of the results of the numerical calculation, the optimization of design of the impeller and the diffuser, and the high-performance operation of the pump.The experiment adopted the technique of 3D-PIV to measure these flow fields in detail for the first time at home, and get the there-dimensional flow fields at the five operation points. The experimental work is under taken on a hydraulic model 150 millimeter. To meet the conditions of measurement, a completely transparent impeller case was packed a quadrate water tank to reduce the error effectively arose by the curve refraction.First, the equipment of axial pump was operated at the steady speed of 1450rpm to get the performance curve and then make sure of five operation points used next. Secondly, the 3D-PIV was applied to get the particle images of the flow fields, in clearance between the impeller and the diffuser, after solving the calibrations of the measurement section in an axial flow pump. Thirdly, the data gained just now was processed with Insight3.4 professional soft to get the three-dimensional velocity vectors, and it were processed post with Tceplot9.0 soft to get the field figs of meridional plane and the isoline maps of velocity distribution, the flow principle of the tested flow fields were analyzed, and compared with the CFD results and the experimental work without the post guide vanes. Last, the causes that produced the deviation in the measurement course were discussed, and then the methods to reduce errors were also put forward.There was obvious there-dimensional flow character in the measured flow fields, but the radial velocity was very small within the runoffs over that one of high-efficiency operating condition point.