含分散相颗粒有化学反应流体R-M不稳定性的数值模拟

Researchers have applied a large amount of studies for the Richtmhyer-Meshkov (R-M) instability formed on the compressible non-reacting single-phase fluid interface for instance impacted by shock wave. However, for the R-M instability occurred in the complicated flows with chemical reacting or laden with dispersed particles, the relative research is rare and there is still lack of knowledge. Based on a hybrid model combing the Eulerian continuous phase and Lagrangian dispersed phase, the present project aims to develop a three-dimensional numerical schemes and algorithms with high accuracy and high resolution, which are suitable for the compressible reacting flows laden with dispersed particles. Therefore, the capture of shocks and fluid interfaces and the track of dispersed point mass particles will be achieved. Based on the database from the numerical simulations, the effects of detailed chemical reactions on the dynamic evolution of fluid interface will be investigated and the action mechanism of reaction in the R-M instability will be revealed. The simulation studies of inert particles and compressible two-phase flows considering one- and two-way coupling will be applied in order to investigate the effects of dispersed particle density, size and mass loading ratio on the dynamic evolution of fluid interface. The present research aims to illustrate the physical mechanism controlling the reacting R-M instability, as well as the interaction between the continuous fluid and dispersed particles and its effect on the evolution of interface. In addition, numerical simulation algorithms and program platforms with independent intellectual property rights will be formed and established, and these research and application have important academic significance and engineering application value.

国内外学者对激波冲击无反应单相流体界面诱导的R-M不稳定问题开展了大量研究，但对于有化学反应或流体中负载分散相颗粒时的R-M不稳定研究则鲜见报道。本项目将基于连续相流体欧拉-分散相颗粒拉格朗日轨道模型的混合方法，发展适用于含分散相颗粒可压缩有反应流动的三维高精度、高分辨率数值格式及算法，实现激波、流体界面捕捉和离散质点颗粒追踪；基于数值模拟得到的数据库，研究详细化学反应对流体界面动力学演化规律的影响，揭示R-M不稳定中化学反应与流动结构发展的微观作用机理；分别开展惰性颗粒与可压缩流体单向、双向耦合的数值计算，探讨分散相颗粒密度、尺度、负载率等参数对界面动力学演化规律的影响。研究旨在揭示有化学反应的R-M不稳定物理机制，连续流体相与分散颗粒的相间作用规律及其对界面演化的影响机制，同时形成和建立我国自主知识产权的强可压缩两相反应流数值模拟算法和程序平台，具有重要的学术意义和工程应用价值。

R-M不稳定性在惯性约束聚变及超声速燃烧等领域具有广泛的应用，然而考虑化学反应及离散颗粒影响的研究则鲜见报道。本项目基于连续相流体采用欧拉方法、分散相颗粒采用拉格朗日方法的混合模式，发展了适用于含分散相颗粒可压缩有反应流动的三维高精度数值模拟方法，实现了激波捕捉和离散质点颗粒的追踪。该方法成功应用于含化学反应和分散颗粒的R-M不稳定性的数值模拟，揭示了化学反应和颗粒相液滴对R-M不稳定性增长机理的影响。通过改变入射激波强度、界面初始幅值、界面初始温度比、颗粒负载率等来说明它们对界面演化的影响。研究发现，1）化学反应对界面扰动幅值增长的影响由化学反应引起的膨胀效应和释热导致的对界面失稳的抑制作用共同决定，且入射激波强度增强，界面扰动幅值增长率增大，流体界面处发展出更多小漩涡，流体之间的相对运动更剧烈，促进了两侧流体掺混；2）负载分散相颗粒使界面形态变得复杂，界面的扩散厚度增大，提高掺混，促进扰动幅值增长；3 ）颗粒使流场中发展出小漩涡，粒径大小对漩涡的产生和发展起重要作用，粒径、入射激波强度和液滴数量增大促进界面扰动幅值增长。总之，研究揭示有化学反应的R-M不稳定物理机制以及连续流体相与分散颗粒的相间作用规律及其对界面演化的影响机制，同时发展了自主知识产权的强可压缩两相反应流数值模拟算法和程序平台，研究成果具有重要的学术意义和工程应用价值。