Similarity characteristics of qualitative and quantitative regulation for adjustable ejector

Abstract

Abstract In the new era of ejector technology entering into system scale from device scale. The methodology of regulation mode of an adjustable ejector has been summarized in this paper. The similarity in characteristics of qualitative and quantitative regulation under different operating modes are researched. The results show that both qualitative and quantitative regulation have the characteristics of ‘constant capacity’. Three different ‘constant-capacity’ phenomena in ejectors have been found, and the similarity indicates that the turbulent flow in ejectors has some statistical invariances in the form of mass flow rate of jetting flow. The ejector has the similar entrainment ability by increasing primary pressure by 43% in the qualitative regulation mode or enlarging the nozzle throat opening by 47% in the quantitative regulation mode under critical mode with similar underexpanded state. The advantages of adjustable ejectors have been promoted, in particular ±5% regulation accuracy or constant regulation ability, discharging improved ability by 80% in flow rate or 10% in pressure lifting ability in subcritical mode or primary flow rate saving ability by 25% or 13% in pressure lifting ability in critical mode.