Experimental Determination of Cavitation Characteristics of Low Specific Speed Pump using Noise and Vibration

摘要

An experimental investigation of the cavitation behaviour of a radial flow pump of metric specific speed 23.62 rpm having different leading edge profiles of the vane is presented. The pump was operated for flow rates from 80 to 120% of the best efficiency point. The measurement included noise and vibration signals apart from the hydraulic parameters. The results exhibited the trends of noise and vibration with respect to percentage of head drops for all operating conditions. It was concluded that the trends were totally different for various flow rates. Hence it is suggested that the criteria to be used for detecting the early cavitation in pump based on noise and vibration signals should be a function of the flow rate. Further, it was found that the range of frequency band for noise and vibration was within 5 kHz with reference to the magnitude of fluctuation. The repeatable predominant frequency of vibration for prediction of cavitation behaviour of this particular pump was established as 0.992 kHz.