Design And Performance Study Of A Two-parameter Adjusting Ejector Under Variable Operating Conditions

Ejector can be widely used in many fields such as refrigeration industry,fuel cell and oil exploitation.Working condition parameters can significantly affect the operation of the ejector,and the change of working condition can sensitively affect the operation performance of the ejector.The research and application value of the performance of the ejector under variable working conditions is great.In order to solve this problem,a two-parameter adjusting ejector is designed,which can ensure stable ejection performance under varying working fluid pressure,mainly including the following three works:1.Based on literature research,this paper explores the relationship between nozzle outlet position and workflow pressure,and between nozzle area ratio and working fluid pressure.Through the reproduction of the literature model,the change rule of the injection ratio after changing the nozzle outlet position and nozzle area ratio under different working fluid pressure is analyzed.The results show that when the nozzle area ratio is changed,the ejector ratio increases first and then decreases with the working fluid pressure,and there is an optimal ejector ratio for each nozzle area ratio in the simulation;when the nozzle position is changed,the ejector ratio also increases first and then decreases with the increase of working fluid pressure,and there is an optimal ejector ratio for each nozzle exit position.2.A kind of two-parameter adjusting ejector is proposed to ensure the optimal performance of the ejector under different working conditions.An elastic actuator,corrugated pipe,is added to the nozzle of the ejector.According to the corrugated pipe principle,the corrugated pipe will shift axially with the working fluid pressure of the ejector,which will change the horizontal position of the nozzle outlet.At the same time,the blocking area between the needle and the nozzle throat will be changed,so as to change the throat area ratio and nozzle exit position of the ejector.3.The two-dimensional axisymmetric modeling and model verification of the proposed two-parameter adjusting ejector are carried out.Through numerical simulation,the effects of variable working fluid pressure,throat area ratio and nozzle exit position on the performance of the ejector are studied,and the relationship between working fluid pressure and optimal throat area ratio and optimal nozzle exit position is fitted,and the linear relationship between them is obtained.Finally,the two-parameters adjusting ejector and the fixed geometry parameter ejector are compared under the same working condition.Therefore,the two-parameter adjusting ejector solves the problem of stable operation under the condition of unstable heat source,and provides a solution for improving performance.