Numerical investigation on the effect of second throat diameter on two-throat nozzle ejector

Abstract

The employment of two-phase ejectors in the CO2 refrigeration systems is widely developed recently. Due to the lack reports on the two-throat nozzle ejectors, the performance of CO2 two-throat nozzle ejector varied with different second throat diameter (D t ) was numerically investigated under different primary pressures (P p ). The accuracy of established numerical simulation model was confirmed with the assistance of experimental data summarized in the literature. The simulated results show that the two-throat nozzle ejector performance corresponding to entrainment ratio (Er) is of better stability with relatively bigger D t under different working conditions. Next, the axial static pressure corresponding to bigger D t is lower than that of smaller one at pre-mixing chamber. And the secondary flow velocity of bigger D t is accelerated better as compared to that of smaller one.