Numerical investigation of an unsteady injection adapted to the continuous detonation wave rocket engine operation

ONERA Chemin de la Hunière, BP 80100, Palaiseau CEDEX 91123, France

Abstract

Detonation applied to propulsion could result in a promising increase of the thermodynamic efficiency of the engine cycle. Numerical simulations of the detonation propagating in the Continuous Detonation Wave Rocket Engine (CDWRE) are currently performed but still do not account for realistic injection process. The assumption of an ideal injected premix is generally chosen for convenience to obtain theoretical results. Comparison of the numerical results with experiments is difficult because of the clear difference of the injection configurations. Some physical aspects of the separate injection of the components used in experiments are not clearly assessed. This study is included in a wider numerical project aimed at designing and optimizing a realistic CDWRE. The optimization process is presently focused on the injector. One element of the injection hole pattern is considered assuming that this element is periodically repeated over the injector head. The aim of the work presented here is to model and analyze the refill process of the components in the combustion chamber behind the rotating detonation. The simulation starts just after the passage of the detonation over the considered injection element. This simulation gives information on the way the injected propellants recreate the reactive mixture for the next detonation. In the first step, two-dimensional (2D) computations helped us to set up the methodology and to study the dynamic response of the fresh components injected. A comparison between 2D homogeneous and separate injections is provided. In the second step, three-dimensional (3D) computations have been performed with a separate injection suitable for the CDWRE operation. Some performance parameters are evaluated such as mixing efficiency or filling of the domain.