Orthogonal Analysis for Structural Optimization of Ejector for Multiejector Air Curtain

ABSTRACT As an important component of the multiejector air curtain for automatic cold store, understanding the impact of the geometric parameters of the ejector on its outlet jet is crucial for boosting its thermodynamic performance. In this paper, three structural parameters of ejector, namely, nozzle diameter ( d 1 ), mixing chamber diameter ( d 2 ), and distance from nozzle to mixing chamber (NXP), were optimized by multi‐index orthogonal test. The numerical simulation was carried out and validated, and the influence of the three factors of the ejector was discussed. The results show that (1) d 1 is the primary factor on all four indicators, while d 2 and NXP are relatively less important factors; (2) Among the 25 ejector structure cases in the orthogonal design, the optimal structural combination of the ejector was determined to be CBE through comprehensive balance method, while the optimal combination scheme was CEE by comparing comprehensive evaluation scores; (3) Compared with OE under all operating conditions, CBE reduces J ac by about 20.9%, but W jb , L jb , and ER are increased by about 38.7%, 42.6%, and 101.9%, respectively. The performance of CEE is slightly better than that of CBE in all four optimization indexes, improving by about 3.9% on average.