Study on the Dynamic Characteristics of Combustion Flow Field in the Scramjet Isolator Under Continuous Variation of Inlet Parameters

This paper investigates the influence of continuous variations in the inlet temperature, pressure, and velocity of the scramjet isolator on the operational stability of the combustion chamber. During the continuous variation of the isolator inlet parameters, the engine’s flow state can be divided into five stages along the time dimension. First, the pressure in the isolator exhibits periodic fluctuations, accompanied by disturbances in the oblique shock wave along the Y-direction. Subsequently, these pressure fluctuations propagate into the combustion chamber, resulting in intense pressure-coupled oscillations between the isolator and the combustion chamber, while the structure of the oblique shock wave undergoes significant changes. Following this, the pressure in the combustion chamber begins to decrease gradually, accompanied by periodic oscillations, and the position of the oblique shock wave in the isolator moves significantly downstream. The pressure oscillations in the combustion chamber then propagate both upstream and downstream, leading to increased pressure fluctuations in the isolator and expansion section, while the volume of the flame stabilization region in the combustion chamber decreases significantly. Finally, under the continuous interaction of these pressure fluctuations, the engine reaches a global pressure equilibrium, and the combustion flow field returns to a stable state.