Abstract

This paper describes the results of an experimental study in which the pressure recovery from a homogenized two-phase flow in a conical diffuser was measured. The flow was an air/water mixture with volumetric void fractions up to 35. Although the pressure recovery was reduced because of the two-phase mixture, the use of a diffuser is still beneficial. For example, whereas a 7° diffuser operating in a single-phase flow achieves a pressure recovery of about 85, the same diffuser operating in a flow with a 20 void fraction has a pressure recovery of about 70; this compares with about 20 through a sudden expansion. It has been found that the optimum angle of the diffuser in two-phase flow is the same as that in single-phase flow, i.e. 7°. The pressure recovery coefficient has been defined using the homogeneous density and the velocity of the mixture at the inlet to the diffuser. An expression is proposed for predicting the pressure recovery coefficient of a diffuser operating in two-phase flow. © 1992.