Novel Approach for Computational Modeling of a Non-Premixed Rotating Detonation Engine

Pressure gain combustion (PGC) has gained significant attention in airbreathing gas turbine applications due to its increased thermodynamic efficiency over a constant-pressure Brayton cycle. Rotating detonation engine (RDE) is a form of PGC, and in most RDEs, fuel and oxidizer are injected into the combustion chamber from separate plenums (for safety reasons), leading to an inhomogeneous mixture in the reaction zone. In this paper, a novel approach is developed to model inhomogeneous injection of the fuel–oxidizer mixture in a two-dimensional computational fluid dynamics analysis. A probability density function (PDF) of the fuel mass fraction from a converged three-dimensional, nonreacting simulation is extracted and is used as a spatially and temporally varying inlet boundary condition in the two-dimensional simulation. Using this method, a numerical analysis is carried out to predict the flow characteristics, flow structures, and detonation cell size of a non-premixed RDE, using H2-air as the fuel–oxidizer mixture. The simulation results are validated against experimental results in the literature, and these results from the non-premixed RDE simulations are compared against a perfectly premixed RDE, under same operating conditions. The present study provides a computationally inexpensive method to model RDE injector designs and helps elucidate the effects of inhomogeneous fuel–air mixing on RDEs.