Heat transfer effects on multiphase Richtmyer–Meshkov instability of dense gas–particle flow

Abstract

Multiphase Richtmyer–Meshkov instability (RMI) widely exists in nature and engineering applications, such as in supernova explosions, inertial confinement fusion, particle imaging velocimetry measurements, and supersonic combustion. Few studies on the effects of heat transfer on the mix zone width have been conducted, and those that do exist are limited to dilute gas–particle flow. To address this research gap, the effects of dense particle heat transfer in a multiphase RMI flow were investigated in this study, and a dimensionless variable that integrates the particle volume fraction and particle parameters was derived for the first time. The results indicate that the effects of dense particle heat transfer cannot be neglected because the volume fraction increases by over three orders of magnitude compared to those in previous studies. Subsequently, numerical studies using the improved compressible multiphase particle-in-cell method were conducted to investigate the effects of heat transfer on the mix zone width. A detailed wave system structure and quantitative budget analyses were performed to investigate the inherent flow characteristics. The heat transfer effect was found to influence the fluid velocity by changing the fluid pressure gradient, thereby reducing the velocity and growth rate of the mix zone. With a Mach number of 2 and a 10% particle volume fraction, the heat transfer reduced the mix zone width by approximately 22%. In addition, simulations with different particle volume fractions and temperature self-similarity demonstrated the correctness and validity of the dimensionless heat transfer time, which is beneficial for predicting the effects of dense particle heat transfer.

颗粒密度与半径影响下的多相rmi混合区域宽度极限理论模型及其规律探究

“…我们使用基于欧拉-拉格朗日框架的 CMP-PIC 方 法来模拟多相流 [23,24] ，该方法可以模拟从稀疏到稠密 以及颗粒流的全流态流动。采用 Runge-Kutta 方法进 行时间推进， 使用 TVD 格式 [26] 来重构原始流动变量， 应用 Harten 等人 [27] 提出的黎曼求解器来求解通量。 将具有相似物理性质的颗粒打包为颗粒包， 并使用软 球模型计算颗粒之间的碰撞，方便相间耦合的计算， 显著降低大规模颗粒群模拟所需的计算量。 CMP-PIC 方法广泛应用于激波-颗粒群作用和多相 RMI 等问题 模拟中，取得良好的应用效果，该方法的验证可参考 已发表论文 [16,17,23,28,29] [13,16,23] 的研究，在每个网格单元布置四个颗粒包，可保证网 格内颗粒包分辨率的收敛。 表 1 四种网格分辨率的详细信息 [16][17][18]22] 。界面的位置定义为空气体积分数 1 0.5…”

“…图 2 四种分辨率下的混合区域宽度 Figure 2 Mixing zone widths of four resolutions 3.2 多相 RMI 模拟算例设置 Ma=1.2 的激波依次通过二维余弦形单模空气/SF 6 界面，空间上均匀分布有直径、密度一致的颗粒[28] ，如图 3 所示。其中，轻流体为空气，重流体为…”

Impact of Temperature Gradients on Multiphase Flow in Air Sparging Remediation Technology

“…Although there are several studies focused on the simulation and prediction of multiphase flows, most research has concentrated on steady-state analysis and has not fully considered the dynamic changes of temperature and pressure over time and their impact on the characteristics of multiphase flows [19][20][21][22]. In addition, the models used in existing research often overlook the complexity of changes in groundwater physical parameters with temperature and pressure, limiting the applicability and accuracy of models under actual complex geological conditions [23,24].…”