The Experimental Study On Floating Impeller Pump Chamber Of The Liquid Pressure

The research of the axial force on the impeller may be reduced to the study on the flowing property of liquids in the pump’s chamber. The research relates to the accuracy of computing the axial force and it is also the weakness of the pump industry. Oversize axial thrust makes accident happening easily. Eliminating or balancing axial thrust not only can improve pump working life and efficiency, but also can make pump trending to high head. For centrifugal pump, using floating impeller to balance axial thrust is different from traditional methods, which integrates balance hole and balance disk onto impeller to make axial thrust self-poise. The main contents of this paper are as follows:This paper takes the centrifugal pump that IS80-50-315as research subject. In order to research the effect of the impeller’s axial displacement to the performance of the pump and the pressure in its cavity, the pressure taps are opened in the pump’s front and back cavity and the impeller’s axial displacement is changed. In order to assuring the measurement accuracy of the liquid pressure in the pump’s front and back cavity, the steady pressure tank is used to eliminate the pressure transient and one pressure gauge is used measure the pump’s front and back cavity pressure.The experiment gets the performance of the pump and the liquid pressure in the pump’s front and back cavity, when the impeller’s axial displacements are0,2,4,6mm. The results of the experiments indicate that as the impeller’s axial displacement gets big, the pump head and efficiency gets low and the shaft power becomes big; the liquid pressure in the pump’s cavity increases with radius and the pressure-radius curve almost is a straight line; with the addition of the impeller’s axial displacement, the liquid pressure in the pump’s back cavity is bigger than the front cavity. When the impeller’s axial displacement is0mm, the radius of pump are146mm,116mm,83mm and the pump’s quality flow are1.0Q, the liquid pressure in the pump’s back cavity is bigger than the front for1.03,0.56,2.52m, the average value is1.37m. When the impeller’s axial displacement is6mm, the liquid pressure in the pump’s back cavity is bigger than the front for1.02,0.21,2.40m, the average value is1.21m.Through the comparative analysis results between the experiment and the theory, indicate that the deviation of the theoretical calculating formula of the liquid pressure in the pump’s cavity is very big. But the theory modifier formulas which the document [34] puts forward have value. This paper can provide reliable information to research the flowing theory of the liquid in the pump’s cavity and the axial force of the floating impeller.Using water as working medium, three kinds of k-ε viscous model were taken to simulate the flow for full pump, which is steady and incompressible. The simulation of pump external characteristics was obtained. Then a viscous model which has the least relative error with experiment was used to simulate the liquid pressure in pump side chamber under different operating conditions. Eventually, the curves of pressure and head were drawn for simulation and experiment. Result indicates that the experimental curve agrees well with the simulation curve, and the former is under the latter. In order to study the relationship between pump side chamber liquid pressure and roughness of flow passage components, the influence which pump shroud inner facer roughness has on pump side chamber liquid pressure was simulated. Result shows that front pump shroud inner facer roughness has a large influence on pump side chamber liquid pressure.