Experimental Investigation of Throatless Supersonic Exhaust on a Rotating Detonation Engine

Abstract

Generating supersonic exhaust without using converging-diverging geometry is an attractive feature desired in all propulsion devices that have supersonic flows. The inherent increased thermodynamic efficiency of combustion by detonation and supersonic azimuthal velocity of the detonation wave front both lend to a sense of curiosity about the possibility of supersonic axial exhaust velocity. Numerical simulations and some experiments have shown that there are oblique shock waves in the exhaust, which are inexorably linked to the detonation wave front. Do these phenomena create the necessary conditions for this to be possible? Experimental investigation into the exhaust characteristics of a rotating detonation engine have yielded very positive results and are discussed in this paper. Also, this engine features a unique injection method for fuel and oxidizer. While there has been some latent desire to explore the flow characteristics of the mixing zone ahead of detonation, aberrant pressure transducer readings on the front end wall of the combustor has been the catalyst into undertaking this task. The results of CFD analysis show possible explanations for this unusual behavior, along with possible explanations for additional effects of engine operation.