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This paper presents the numerical simulations of a Rotating Detonation (RD) propagating in a layer of combustible mixture, created by injection of gaseous hydrogen and oxygen. 3D Large Eddy Simulations (LES) of a reacting flow have been performed in a domain of planar geometry with different injector types operating in the regimes of premixed and separate propellant injection. A quasi-2D case with uniformly distributed premixed injection is first simulated to characterize the RD propagation under the most idealized conditions. Then, the simulations are performed with a 3D injector of the semi-impingement (SI) concept under the conditions of premixed and separate injection of the propellants at globally stoichiometric proportions. The case of separate propellant injection is the most realistic one. The computational results, represented by instantaneous and averaged flowfields, are analyzed to point out the changes in the conditions of RD propagation induced by the injection through discrete holes with respect to the distributed one and by the switching between the premixed and separate regimes. Besides the SI concept, an improved (Imp) concept for the injector has been designed to improve the mixing efficiency in the fresh mixture layer. Macroscopic quantities, such as the RD propagation speed, average parameters of the fresh mixture, and mixing efficiency are evaluated and compared in order to characterize the studied effects for the simulated cases. |
