Performance Prediction of Compressible Two-Phase Flow through Ejectors

Document Type : Original Article


Mechanical Power Engineering Department, Faculty of Engineering, Menoufiya University, Shebin El-Kom, Egypt.


The objective of present work is to investigate theoretically the performance of two-phase flow
(gas-liquid) through ejectors. The numerical investigation is based on non-homogeneous, (liquid
and vapor velocities are not equal), non-equilibrium (liquid and vapor temperatures are not equal),
two-fluid model, (Eulerian-Eulerian), conservation equations governing steady, two–dimensional
(axisymmetric), turbulent, compressible, and parabolic two-phase flow. These equations are
namely continuity, momentum, and energy. These equations are solved iteratively using control
volume method with Prandtl’s mixing length as a turbulence model. Mass and heat transfer
between the liquid and vapor phases are considered. Wall function is used instead of using very
fine grid near the wall. The coordinates system is converted to bodyfitted coordinates. Refrigerant
134a is used as a working fluid. The Modified Benedict-Webb-Rubin (MBWR) equation of state is
used to represent compressibility. The presented model is validated against previously published
data in literature. The validation showed reasonable agreement. Effects of changes in geometry
and operating conditions on ejector performance are investigated. Moreover, effects of certain
parameters on ejector efficiency are presented showing that, for maximum efficiency both
geometrical and operational parameters must be carefully selected. Overall, the results lead to
useful information for ejector optimum design and prediction of the ejector behavior and