固体火箭发动机中声场对凝聚相粒子的影响

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

关键词:  固体火箭发动机  燃烧不稳定  声场  凝聚相颗粒流  数值模拟

Key words:  Solid rocket motor  Combustion instability  Acoustic field  Condensed particle flow  Numerical simulation

摘要:

为研究固体火箭发动机中声场对凝聚相粒子的影响，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，获得了发动机声场与凝聚相粒子的耦合作用规律。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。另外，发动机中不同振型的声场对粒子的影响也显著不同。径向声场力会使得凝聚相粒子往模型的中心区域汇聚，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，粒子呈现周期性往复运动，且在模型尾部一定位置发生碰撞聚集；颗粒相沿轴向的速度分布整体上呈现先增大后减小的变化规律，而粒子在碰撞聚集位置速度发生骤变。

Abstract:

The continuous phase-discrete element （CFD-DEM） coupling model was applied to the study of particle behavior under the action of multiphysics in solid rocket motors， and the effects of acoustic field on particle behavior were studied. Then the coupling law of the two-phase flow and the acoustic field of the motor was obtained and analysed. The results show that the CFD-DEM model can obtain microscopic information of particles that cannot be obtained by other models， such as particle-particle collision， particle-gas interaction force and particle-wall colliding force. In addition， the effects of different acoustic vibration model on the particles in the motor are also significantly different. The radial acoustic force will cause the condensed phase particles to converge toward the central region of the combustion chamber， while near the wall area is essentially a particle vacuum region， the spatially uneven distribution of the particles is extremely remarkable. Under the action of axial acoustic force （first-order fundamental frequency acoustic wave of the motor）， the particles periodically reciprocate and collide at a certain position at the tail of the model. The velocity distribution of the particle phase along the axial direction increases at first and then decreases， while the speed at which the particles collide gathers suddenly changes.