Reduction of Feedback Pressure Perturbation for Rotating Detonation Combustors

The transient pressure propagation induced by the unsteady but stable rotating detonation combustor can lead to degradation of the compressor performance and stability. In this study, the propagation characteristics of feedback pressure perturbation are firstly investigated based on numerical simulations of internal flows. Then a form of isolator configuration, which is a cylinder with several rows of wedge obstacles on the inner wall, is constructed aiming at weakening the pressure perturbation. Furthermore, a preliminary optimization design criterion of the isolator is proposed based on balance between the feedback pressure reduction and total pressure recovery. The results show that, the feedback pressure perturbation mainly propagates upstream along the axial and circumferential direction against the outer wall of the flow channel. Meanwhile, the peak pressure slowly decays during the propagation of the pressure perturbation along the axial direction, and the feedback pressure perturbation rotates in the same direction as the detonation wave with a phase lag in the circumferential direction. The isolator with a series of wedge obstacles on the inner wall can accelerate the decay of the feedback pressure perturbation. Increasing the number of obstacles, the dimensionless height, width and spacing have a positive impact on the reduction of the pressure perturbation, while the effect of increasing the inclination angle is just opposite. Meanwhile, an expanded channel for the isolator is more beneficial for reducing the feedback pressure perturbation.