Analysis on cavitation characteristic in centrifugal pump

According to the formula of net positive suction head of centrifugal pump,the main factors which affect pump cavitation are the design of pump casing and impeller inlet.The formula of cavitation specific speed is rewritten into a new form related with blade inlet angle,hub-tip ratio and the two factors mentioned above.A diagram is drawn to show the design variables that have effect on the cavitation specific speed.By the diagram,it can be deduced that the optimum blade inlet angle for maximum cavitation specific speed is in the range of 10 to 30 degres.The factor related with impeller has more effect on the cavitation specific speed than that with casing.The cavitation incipient criteria show that any pump works under the condition of cavitation.Therefore,a valid curve,which corresponds to the 0.5% head-drop curve,is recommended here to limit the running range for pump at cavitation condition.