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惯性颗粒在非均匀加速流中的输运问题-2021增刊

李青1,涂国华2,余钊圣3,林昭武3,李婷婷4,袁先旭2   

  1. 1. 中国空气动力研究与发展中心,空气动力学国家重点实验室
    2. 中国空气动力研究与发展中心
    3. 浙江大学航空航天学院
    4. 西安交通大学
  • 收稿日期:2021-09-15 修回日期:2021-10-07 出版日期:2021-10-12 发布日期:2021-10-12
  • 通讯作者: 袁先旭
  • 基金资助:
    国家重点研发计划:高超声速湍流与多物理场耦合机理研究

Inertial particle transport in non-uniform accelerated flow

  • Received:2021-09-15 Revised:2021-10-07 Online:2021-10-12 Published:2021-10-12
  • Contact: Xianxu XianxuYuan

摘要: 基于新型碳基颗粒增强或碳基纤维材料的再入体热烧蚀问题对飞行器的气动力/热性能影响机理尚不明确。 初步研究不考虑化学反应和气体引射效应,把热烧蚀问题中的颗粒剥离问题模化为一个驻点流中的离散颗粒启动问题。 由于高速气流在驻点温度达到上万度量级,局部马赫数接近于零,研究近似假设靠近壁面的流体动力学为不可压缩的,并使用不可压缩的颗粒解析的直接数值模拟方法Particle-Resolved Direct Numerical Simulation(PR-DNS)来研究一个惯性颗粒在平面挤压/拉伸流和壁面驻点流中的动力学,从而揭示在驻点流中的颗粒输运机理。 研究发现:1.惯性颗粒在面挤压/拉伸流中受到的总气动力近似等于相同颗粒滑移雷诺数下均匀来流的阻力;2.颗粒在壁面驻点流中的输运机制是水平输运,几乎没有垂直输运,与平行剪切颗粒床输运非常不同,这是驻点流特有的垂直向下挤压作用导致的。

关键词: 挤压拉伸流, 壁面驻点流, 颗粒输运机制, 热烧蚀颗粒, 颗粒解析的直接数值模拟

Abstract: The effect of thermal ablation of novel carbon fiber composites material on the aerodynamic force and heat is not fully understood. As a primary research, without considering the chemical reaction, gas injection and other complicate physical process, assume the particle loss from the vehicle surface as a discrete particles dynamics problem. Due to the high temperature in the near wall, local Mach number is vanishingly small, near wall fluid flow can be treated as incompressible. Therefore, Particle Resolved Direct Numerical Simulation (PR-DNS) of incompressible flow can be used to study the particle dynamics in a straining flow and wall-bounded stagnation point flow. It has been found that: 1. The total aerodynamic force of large density ratio particle in straining flow is approximately equal steady drag in a uniform flow with the same particle slip Reynolds number; 2. The particle transport in a wall-bounded stagnation point flow is horizontal, with minimal vertical transport, which is very different from that of parallel shear flow over a particles bed. This is due to the normal hydrodynamic force of stagnation point flow.

Key words: straining flow, wall-bounded stagnation point flow, ablation particle, particle transport, PR-DNS