Experimental study of a planar expansion-deflection nozzle

Institute of Space Propulsion German Aerospace Center Lampoldshausen, Hardthausen 74239, Germany

Abstract

A planar expansion-deflection (ED) nozzle was tested in the cold-flow P6.2 test bench at German Aerospace Center (DLR) Lampoldshausen. The comparison between design, experimental data, and numerical results at the design point of p₀/p_a = 30 shows, in general, a good agreement with slight discrepancy due to a higher expansion in the experiments. The center-body base wake closure was studied from transient pressure profiles (p₀/p_a = 15-25). A hysteresis was shown to exist in the transition from the open to the closed wake mode and back. For lowpressure ratios (p₀/p_a = 6, i. e., off-design operation), flow separation on the center body occurred. The related separation shock was shown to interact with the opposite outer contour leading to pressure peaks.