A steam ejector can effectively utilize waste heat resources, which is widely used in the fields of air conditioning, refrigeration, and seawater desalination. The structure of the steam ejector’s mixing chamber has a critical influence on its performance. In this paper, the effects of the mixing chamber length on the steam ejector performance under different Mach numbers at the nozzle exit, constant area section length, and diffuser length are studied using three-dimensional (3D) numerical simulations. The numerical simulation results show that the entrainment ratio and critical back pressure of the steam ejector rise first and then decrease with the increasing of the mixing chamber length under different Mach numbers, constant area section lengths and diffuser lengths. The steam ejector can achieve a better performance with the mixing chamber length in the range of 40 mm to 80 mm, when the nozzle throat diameter is 2.5 mm under a typical working condition of steam ejector refrigeration.

蒸汽喷射器可以有效地利用废热资源，该废热资源被广泛用于空调，制冷和海水淡化领域。蒸汽喷射器混合室的结构对其性能有至关重要的影响。在本文中，使用三维（3D）数值模拟研究了混合腔室长度对喷嘴出口处不同马赫数，恒定截面积长度和扩散器长度下蒸汽喷射器性能的影响。数值模拟结果表明，在不同的马赫数，恒定的截面长度和扩散器长度的情况下，随着混合室长度的增加，蒸汽喷射器的夹带率和临界背压先上升，然后下降。