Numerical investigation of the effect of equivalence ratio on the propagation characteristics and performance of rotating detonation engine

The equivalence ratio is one of the significant factors affecting the propagation characteristics and performance of the rotating detonation engine (RDE). Using the compressible reacting flow solver based on the OpenFOAM open-source platform, the effect of different equivalence ratios of premixed H₂/Air gases on the propagation characteristics and performance of RDE under different total inlet pressures (P₀) is investigated. The reactants are injected through the discrete inlet to mimic the spatial inhomogeneity of the reactants in the actual RDE combustor. The results indicate a Y-shaped flow field structure is formed behind the rotating detonation wave (RDW) using the discrete inlet. There is only one RDW in the flow field with the change of the equivalence ratio when the P₀ is 0.5 MPa, and the primary factors affecting the RDW propagation velocity differ under fuel-lean and fuel-rich conditions. The RDW propagation mode switches from single-wave to co-directional double-wave and double-wave collision with the change of the equivalence ratio when the P₀ is 1.2 MPa. The velocity deficit of RDW in the double-wave mode is larger than that in the single-wave mode. Additionally, in the single-wave mode, the specific impulse decreases as the equivalence ratio increases, but the specific thrust increases as the equivalence ratio increases. When the propagation mode changes, the specific impulse and specific thrust show different trends with the change of the equivalence ratio. It demonstrates that multiple co-directional RDWs have the effect of stabilizing the thrust.