Numerical and Experimental Analysis of Single-Phase and Two-Phase Flow in Ejectors

Abstract

This paper presents results from an ongoing research effort to study single-phase and two-phase flow in ejectors numerically and experimentally. The goal of this study is twofold. The numerical analysis is intended to explore the details of the complex flow patterns within an ejector to help design more efficient ejectors. The experimental study was mainly intended to verify the feasibility of an idea previously proposed by the authors. This idea is to introduce fine droplets of a nonvolatile liquid into the driving fluid flow to reduce irreversibilities in the mixing chamber, thereby improving the overall efficiency of the ejector. The numerical results show that CFD analysis can be a very helpful and often reliable tool to understand the complex flow patterns within ejectors. Those results show some interesting flow phenomena that have not been adequately addressed in the literature. It was also found that CFD results are strongly dependent on grid resolution and the turbulence model employed. The experimental results show that two-phase flow can indeed be advantageous in certain cases. The limitations of this idea are discussed in some detail.