Numerical investigation of exit pressure on flow structure in steam ejector by considering condensation and evaporation process

Nowadays, it is very important to use renewable refrigeration cycles due to the high consumption of electrical energy by existing refrigeration cycles. The ejector refrigeration cycle (ERC) is one of these cycles in which the ejector is the most important part. This study has investigated the effect of ejector outlet pressure on flow structure. Several outlet pressures are considered, and their effect on pressure, velocity, temperature, liquid mass fraction (LMF), and Entrainment ratio (ER) are investigated. First, the flow simulation in the ejector is validated. Then, the impact of output pressure is evaluated. According to the results, the used model can well estimate the flow behavior in the ejector. The impact of the outlet pressure in the diffuser part and the constant area section leads to the difference in the distribution of temperature, velocity, pressure, and LMF. The LMF becomes zero at x = 0.41 m, x = 0.36 m, x = 0.32 m, and x = 0.27 m for pressures of 3600 Pa, 4000 Pa, 4200 Pa, and 4500 Pa, respectively, and the flow becomes single-phase, and a temperature increase is seen in the flow. Outlet pressure has a substantial impact on ejector performance as well as ER, and as outlet pressure from 3600 Pa, the ER decreases.