An aerospike nozzle ejector in MED-TVC systems for performance improvement and operating condition extension

Aerospike nozzles, characterized by its distinct structure diverging from the conventional bell nozzle, are commonly employed in aerospace propulsion systems. This structural configuration confers performance advantages under specific operating condition. In this paper, an aerospike nozzle is firstly introduced into the steam ejector in multi-effect distillation (MED) systems to solve the problem of performance degradation caused by unstable steam source pressure in the traditional ejector. The effect of the aerospike nozzle structure with different throat radiuses on the performance of the aerospike nozzle ejector (ANE) is investigated. The simulation results show that when the throat radius is 4 mm, the entrainment ability of the ANE is optimal. Moreover, the effect of boundary conditions on the entrainment capacity is analyzed. With the increase of primary pressure, the critical pressure of the ANE increases and the critical ER decreases. The entrainment ability and back-pressure sensitivity of the traditional ejector and ANE is compared and analyzed. The results show that while ensuring the unchanged back-pressure sensitivity, the average and maximum increasing rates of the ANE performance in the low-pressure range is 89.21 % and 378.57 %, respectively, and the ER increasing rate is 45.18 % under wide operating conditions.