Modulation of a R245fa Supersonic Ejector By A Movable Needle: A Numerical Study

Abstract

The current study explores the performance of a variable geometry ejector (VGE) working with R245fa. The ejector is equipped with a needle that controls the primary nozzle throat area (A t ). The nozzle head exit position (NXP) is also adjustable. Three different primary nozzle throat area values are tested: 1.00A t , 0.80A t , and 0.61A t . The performance curves of both CFD and experimental tests are compared. The k-ω SST shows good agreement with the experimental values. Changes to the shock train formation are also observed. The effect of the needle on the reduced primary mass flow rate is compared to a primary pressure reduction.