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 ${\mathrm{H}}_2$-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.

压力增益燃烧（PGC）由于在恒定压力的布雷顿循环中提高了热力学效率，因此在呼吸式燃气轮机中得到了广泛的关注。旋转爆震发动机（RDE）是PGC的一种形式，在大多数RDE中，燃料和氧化剂是从单独的充气室喷入燃烧室的（出于安全原因），导致反应区的混合物不均匀。在本文中，开发了一种新颖的方法来在二维计算流体动力学分析中对燃料-氧化剂混合物的不均匀注入进行建模。从会聚的三维非反应模拟中提取燃料质量分数的概率密度函数（PDF），并将其用作二维模拟中随时间变化的进气边界条件。使用这种方法${\mathrm{H}}_2$-空气作为燃料-氧化剂的混合物。仿真结果已针对文献中的实验结果进行了验证，并且在相同的操作条件下，将非预混合RDE仿真得到的结果与完美预混合RDE进行了比较。本研究提供了一种计算上不昂贵的方法来对RDE喷油器设计进行建模，并有助于阐明燃料和空气混合不均匀对RDE的影响。