Characterization and predictive modeling of intake blockage in rotating detonation combustor

The intake blockage of the rotating detonation combustor (RDC) results from the interaction between the high-pressure detonation wave and the intake air of the combustor, which affects the working stability and performance parameters of the combustor. Based on this research background, a series of experiments were conducted under different flow rates and nozzle structures. A method for calculating the intake blockage based on the throat pressure of the combustor was proposed. The intake characteristics of the combustor under three intake states were analyzed, and the discrimination criteria for different intake states of the combustor were proposed. The proportion of intake blockage of the combustor was fitted by the dimensionless discrimination parameters. After correction by the fitting function, the proportion of intake blockage of the combustor was predicted with high accuracy ( R 2 = 0.98 ). The propagation mode and stability of the detonation wave under different working conditions were analyzed, and the relationship between the proportion of intake blockage and the propagation characteristics of the detonation wave was explored. It was found that when the proportion of intake blockage was zero, the detonation wave propagated in a single wave mode. With the decrease in throat flow capacity and the increase in intake blockage ratio, unstable modes begin to occur, accompanied by reduced stability in detonation wave propagation. When the throat was in fully subsonic flow, the intake filling speed of the combustor decreased significantly, and the longitudinal pulsed detonation mode were easily induced. The relationship between the intensity of the pressure feedback and the upstream chamber pressure rise ratio and the intake blockage was analyzed, and the relevant relationships were fitted for the construction of the prediction model. The research results show that with the increase of the proportion of intake blockage, the intensity of the pressure feedback and the upstream chamber pressure rise ratio both increase. The intensity of the pressure feedback is affected by many factors and is simultaneously influenced by the detonation wave intensity and the throat flow state, so its fitting accuracy is relatively low ( R 2 = 0.855 ). However, the upstream chamber pressure rise is mainly induced by the intake blockage, so a higher fitting accuracy can be achieved ( R 2 = 0.98 ). However, due to the additional aerodynamic losses caused by the feedback shock wave, the predicted results are lower than the experimental measurement values. In summary, this research work clarifies the relationship between the intake blockage of the rotating detonation combustor and the working characteristics of the combustor, which is of great significance for fully understanding the working principle of the rotating detonation combustor and guiding the structural design of the combustor.