An Experimental and Theoretical Investigation of Two-Dimensional Centrifugal Pump Impellers

Abstract

An experimental and theoretical investigation on a series of three centrifugal pump impellers has been made in order to determine the usefulness and validity of tyro-dimensional potential theory for the description of the flow. Computed values of the developed head and distribution of pressure on the vane surfaces are compared with measurements an two-, four-, and six- bladed impellers which have 30° logarithmic spiral vanes and a radius ratio of about one-half. It is found that for operating points where the influence on the flow into the impeller by the inlet turn is least, the agreement between the observed and predicted values is reasonably good, while for other flow rates large discrepancies occur. Although the impeller efficiency is relatively high when the flow is least disturbed by the inlet, the slope of the work coefficient line is steeper than the theoretically predicted value. This deviation is attributed to boundary layers which are observed on the vane surfaces.