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

Abstract

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.

A diffuse interface method for solid-phase modeling of regression behavior in solid composite propellants

“…The second is to use the level-set (LS) method, which relies on the evolution of a surrogate field, the isocontours of which are regarded as a sharp surface. This was originally applied by Wang et al [35] and others [36,37] to modeling surface regression in SCPs. Here, surface regression is effected by local calculation of regression rate, which is used to update the surrogate field at the interface.…”

Evaluation of Mechanical Properties of Composite Solid Propellant by Genetic Engineering of Materials: Part B: Modeling of Minimum Representative Unit for Multi‐Modal Particle Packing Structure Based on Formulation of Composite Solid Propellant

“…The combustion property of composite solid propellant is significantly affected by the mesoscopic structure of the burning surface [2, 3], which means that the burning rate at each point on the burning surface is different. However, the measured burning rate is usually an average value and not enough to characterize the propellant combustion property in detail.…”

Characteristics of the Reacting Flow for the Base‐Bleed Projectile under Dual Stress

“…It was observed that the combustion efficiency obtained by a multi-location swirl injection gives a lower improvement with a 24 L/D motor (from 70 % to 76 %), but the improvement was significant with a 12 L/D motor with a single swirl injector (from 50 % to 74 %). Ye [10,11] established a two-dimensional periodic sandwich steady rotating combustion model of AP/HTPB, and the flame structure was simulated under the combustion pressure of 0.1-5.0 MPa and spinning speed of 0-10 800 rpm. He found that the deflecting angle of the gas flame is linearly positive with the pressure, and the trend of the average Reynolds number on the combustion surface is the same as the deflection angle of the gas flame.…”