固体火箭发动机中声场对凝聚相粒子的影响

固体火箭发动机中凝相粒子的空间非均匀分布不但会改变粒子的阻尼效果，还可能对金属粒子的分布式燃烧产生影响，从而显著改变发动机内的增益和阻尼。粒子的空间分布受发动机内部固有的声场压强振荡的影响，进而影响粒子对声振荡的阻尼效果。本文将连续相-离散元（CFD-DEM）耦合模型应用于固体火箭发动机中多物理场作用下的粒子行为研究，实现了声场对粒子行为的影响研究，获得了发动机两相流流动与声场的耦合作用规律。结果表明：CFD-DEM模型可以获得其他模型无法得到的颗粒微观信息包括颗粒与颗粒间的碰撞、颗粒与壁面的碰撞以及颗粒与气相间的相互作用等。另一方面径向声场力会使得凝聚相粒子往发动机燃烧室的中心区域汇聚，并且形成稳定宽度的粒子质量分数高达90%以上的聚焦带，而在壁面区域基本为粒子真空区域，粒子的空间不均匀分布极其显著。轴向声场力（发动机一阶基频声波）作用下颗粒分布在声场波节节点后可以观察到较高浓度粒子区减少，颗粒分布不似无声场作用那样密集，且颗粒相沿轴向的速度分布呈现先增大后减小的变化规律，在节点附近达到峰值。

Effects of Acoustic Force Acted on Condensed Particles in Solid Rocket Motor

The spatially non-uniform distribution of condensed particles in a solid rocket motor not only changes the damping effect of the particles, but also affects the distributed combustion of the metal particles, thereby significantly changing the driving and damping in the motor. The spatial distribution of the particles is affected by the inherent acoustic pressure oscillation , which in turn affects the damping effect of the particles on the acoustic oscillation. In this paper, the continuous phase-discrete element (CFD-DEM) coupling model is applied to the study of particle behavior under the action of multiphysics in solid rocket motors. The results show that the CFD-DEM model can obtain microscopic information of particles that cannot be obtained by other models, including collision between particles and particles, or between particles and walls, and interaction between particles and gas phase. On the other hand, the radial acoustic force will cause the particles to converge along the central axis of the rocket motor combustion chamber and form a stable width of the focus band, while in the wall region is substantially a particle vacuum region, the spatially uneven distribution of the particles is extremely significantand. Under the action of acoustic field (first-order fundamental frequency acoustic wave of the motor), the particle distribution in the acoustic field node can be observed to decrease the particle concentration of the higher concentration, the particle distribution is not as dense as the no acoustic field condition, and the velocity distribution of the particle phase along the axial direction will reach a peak near the node.