Acoustic Analysis in Small-scale Rotating Detonation Engines

Abstract

Rotating detonation engines (RDEs) have been at the forefront of cutting-edge research for the last few decades due to their potentially high thrust-to-weight ratio, compact size and ease of manufacturability. RDEs are typically annular designs in which a detonation wave spins around a cylindrical annular region. However, recent research shows that coreless RDEs, an innovative design with the inside core removed, hold promise for small-scale RDEs in particular. In this work acoustic analysis is carried out on two sizes of smale-scale RDEs, of 10 mm and 25 mm outer diameter, in both hollow and annular configurations. The resulting operating modes and frequencies are compared with recent experimental data obtained using both hydrogen-oxygen and methane-oxygen gaseous propellant mixtures. Additionally, as-yet-unpublished data for the 10 mm configuration with heated propellant is analyzed and reported, and recommendations for prospective work to further establish the acoustic modes and mechanisms of RDEs are given.