Effects of Reversed Shock Waves on Operation Mode in H2/O2 Rotating Detonation Chambers

Abstract

Operation modes are an important topic in the research of Rotating Detonation Chamber (RDC) as it can affect the stability of RDC. However, they have not been discussed in detail due to the limitation of measurement means in experiments. The aim of this research is to investigate the mechanism of different operation modes by numerical simulation. In this paper, a numerical simulation for RDCs with separate injectors is carried out. Different operation modes and mode switching are analyzed. There is a series of reversed shock waves in the flow field. It was found that they have great effects on operation mode and mode switching in RDCs. A reversed shock wave can transit into a detonation wave after passing through isolated fresh gas region where fresh gas and burnt gas distribute alternatively. This shock-to-detonation transition (SDT) phenomenon will influence the ignition process, contra-rotating waves mode and mode switching in RDCs. SDT makes the number of detonation wave increases, resulting in multi-wave mode with one ignition. Moreover, quenching of detonation waves after collision and SDT after passing through isolated fresh gas region are the mechanism of contra-rotating waves mode in RDCs with separate injectors. In addition, when the inlet total temperature increases, a shock wave is easier to transit into a detonation wave. The distance that a shock wave travels before SDT decreases when temperature increases. This will result in mode switching. Therefore, SDT determines that there is a lower bound of detonation wave number.

BYCFoam: An Improved Solver for Rotating Detonation Engines Based on OpenFOAM

“…Figure 14 illustrates the schematic of an RDC in a 2D computational domain (12 cm × 4 cm). The premixed stoichiometric hydrogen/air mixtures were injected into the combustor through the bottom boundary with Laval nozzle inlet conditions [8,9]. The area ratio of nozzle was 1.7.…”

“…Consequently, numerical simulations are popularly employed to gain a deeper understanding of the complicated phenomena in detonation processes. Chen et al [8] and Liu et al [9] investigated the effects of reversed shock waves on the operation mode in a hydrogenfueled RDE with a fifth-order WENO code. In the work by Mikhalchenko et al [10][11][12], three-dimensional (3D) numerical modeling were conducted with different reactant mixtures and RDE configurations to study the effects of the detonation onset in the transition period.…”

A Numerical Approach to Optimize the Design of a Pintle Injector for LOX/GCH4 Liquid-Propellant Rocket Engine

“…The velocity of propellant injection should be slower than the sonic velocity. It is not desirable because the supersonic injector rockets are less efficient than the sonic injectors and produce less thrust per unit mass flow [41], and the combustion chamber can be highly harmful when a supersonic flow is present because it cause high pressure and shock wave [42][43][44].…”