Experimental investigation of thrust augmenting ejectors using vane excited primary jets

Abstract

An experimental investigation has been conducted to evaluate the entrainment characteristics of a thrust augmenting ejector, with a small, oscillating airfoil inserted in the potential core of the primary jet. Velocity distributions were measured across the width of the jet, at downstream distances of 20 and 40 nozzle widths, with the jet exhausting into still air and with the jet exhausting into an instrumented ejector shroud, for the following range of parameters: Pressure ratio 1.137 and 1. 268, amplitude of oscillation 2.6° and 6.9° zero-to-peak, frequency of oscillation 0, 20, 40 and 60 Hz. Static pressure distributions were measured within the shroud when the ejector was installed. The results amplify previously conducted studies. Jet spreading and entrainment appear to increase with increasing amplitude and frequency of oscillation and to decrease with increasing nozzle pressure ratio.