关键词: 喷射器, 圆柱形混合室, 圆锥形混合室, 喷射系数

Abstract: Considering expansion and compression ratios, the entrainment ratio was analyzed for ejectors with cylindrical and conical mixing chambers using water, ammonia, R290, R22 and R134a as working fluid separately.The equivalent compression ratio, equivalent parameter line and equivalent parameter region of entrainment ratio were defined.At a constant expansion ratio, the cylindrical mixing chamber can reach a higher entrainment ratio than the conical chamber when the compression ratio is smaller than the equivalent compression ratio of entrainment ratio, and different case will occur when the compression ratio is less than the equivalent one of entrainment ratio.The equivalent parameter line of entrainment ratio shows that the equivalent compression ratio decreases with the increase of expansion ratio.In the equivalent parameter region of entrainment ratio, the two types of ejectors have almost the same efficiency.A cylindrical mixing chamber ejector is prior when compression ratio and expansion ratio locate in the left of the equivalent parameter region of entrainment ratio, while a conical mixing chamber ejector is preferable when they are in the right.The location of equivalent parameter region is determined by the adiabatic exponent.

Key words: ejector, cylindrical mixing chamber, conical mixing chamber, entrainment ratio