NUMERICAL SIMULATION AND AUXILIARY ENTRAIMENT OF STEAM EJECTORS

The numerical results disclose that there are several locally low-pressure areas inside a well-designed steam ejector. Based on this finding, a so-called auxiliary entrainment technology is proposed to entrain extra entrained steam by connecting these locally low-pressure areas to the suction chamber of the entrained steam. Then numerical simulations are carried out of different auxiliary entrainment schemes. The results reveal that although the auxiliary entraining entrance of the mixing chamber auxiliary entrainment can entrain some low-pressure steam into the ejector, the auxiliary entrainment results in a decrease in the entrained steam mass flow rate of the main entrained steam entrance that is greater than the auxiliary entrainment steam mass flow rate. However, it is also disclosed that the throat auxiliary entrainment does increase the entrainment ratio of the steam ejector. The best result obtained in our simulation is that the ejector entrainment ratio is increased by 3.68%. Therefore, it may be concluded that auxiliary entrainment may be an effective way for improving the performance of steam ejectors, although its feasibility needs proving experimentally.