Some Experiments on an Air-Water Two-Phase Flow Pump Impeller with Rotating-Stationary Circular Cascades and Recirculating Flow Holes

Abstract

Gas accumulation and its elongation in a centrifugal impeller of liquid/gas two-phase flow pump cause head degradation. In order to decrease the head degradation, a special type of open impeller has been designed on the basis of the following concepts. A designed impeller consists of two stages of rotating and stationary circular cascades to create a dispersive effect of each cascade inlet for gas-phase flow. The outer rotating cascade has a large blade outlet angle to keep the pump head high even at high void fraction. Holes made through the rotating disk, through which recirculating liquid flows may blow off the gas accumulating region, are equipped in each flow passage. This newly conceptualized impeller was examined experimentally. Results are discussed in the present paper on how to improve the two-phase flow performance.