CFD analysis of operating condition effects on optimum nozzle exit position of a supersonic ejector using the refrigerant R134a

Abstract

In this work, the computational fluid dynamics technique is employed to study operating condition effects on the optimum value of an important parameter called the nozzle exit position (NXP) for an ejector design. This ejector uses the gas R134a as the working fluid. Numerical tests are carried out using a combination of the REFPROP 7.0 database state equation and the high-Reynolds version of the SST k–ω model. Good agreement in terms of entrainment ratio and critical temperature is obtained between computed values and measurements. In addition, numerical results indicate that the optimum NXP maximizes ejector performance and is highly dependent on operating conditions.