Numerical Simulation and Unsteady Combustion Model of AP/HTPB Propellant under Depressurization by Rotation

In order to study micro-scale combustion characteristics of base-bleed propellant ammonium perchlorate/hydroxyl terminated polybutadiene (AP/HTPB) under rotation condition, a two-dimensional unsteady rotating combustion model of periodic sandwich model of AP/HTPB was established. In the gas phase, a two-step overall reaction was used to couple the gas-solid boundary layer, the rotational momentum was fitted and the numerical simulation comparative analysis under the initial combustion pressure of 0.1 MPa-5 MPa and the rotation velocity of 0-10 800 r min(-1) was experimented. The results show that under the conditions of an initial combustion pressure of 3.5 MPa, a depressurization rate of 1000 MPa s(-1) and a rotation velocity of 10 200 r min(-1), the formation of a narrow diffusion-controlled chemical reaction zone appears in the initial stage of depressurization. When the combustion pressure drops to about 0.88 MPa, the flame shows dual characteristics: diffusion-controlled and premixed combustion. When the pressure dropped to 0.1 MPa, the flame is premixed combustion. The steady combustion process at different combustion pressures and different rotational velocities was analyzed numerically. The results show that there is a linear positive correlation between the flame deflection angle and the pressure. When the rotation velocity is lower than 10 000 r min(-1), the deflection angle of the gas flame increases linearly with the rotation velocity. However, when the rotation velocity is higher than 10 000 r min(-1), the deflection angle and the rotation velocity of the gas flame increase exponentially. The trend of the average Reynolds number of the combustion surface is basically the same as that of the deflection angle of the gas flame. Therefore, the average Reynolds number of the combustion surface can be used to describe the influence of rotation and pressure on the deflection angle of the gas phase flame.