A numerical method for shock driven multiphase flow with evaporating particles
A numerical method for shock driven multiphase flow with evaporating particles
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DOI：
10.1016/j.jcp.2017.04.074
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发表时间：
2017-09
期刊：
影响因子：
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通讯作者：
Jeevan Dahal;J. McFarland
中科院分区：
文献类型：
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作者：
Jeevan Dahal;J. McFarland
本文提出了一种预测激波驱动流中活性相变颗粒相互作用的数值方法。采用粒子单元(PIC)技术，将拉格朗日坐标系中的粒子与欧拉坐标系中的流体相耦合。采用分段抛物线法(PPM)流体动力学求解器求解守恒方程，并对粒子相的质量、动量和能量源项进行了修正。该方法已在芝加哥大学开发的开源流体动力学软件Flash中实现。通过将单个粒子模拟的速度和温度历史与解析解进行比较，完成了对方法的简单验证。此外，在两种不同尺寸下进行了简单的单颗粒模拟，以研究激波驱动的多相不稳定中颗粒尺寸对涡量沉积的影响。由于颗粒涡度源项的平流通过载气，大颗粒的前期拟能产生量较低，后期拟能耗散较高。对二维激波驱动的圆形扰动不稳定性进行了数值模拟，并与已有的实验数据进行了比较，进一步验证了数值方法的有效性。对于这种情况，进一步考察了颗粒大小分布和颗粒蒸发的影响。结果表明，较大颗粒减少了涡量沉积，颗粒蒸发则增加了涡量沉积。结果还表明，在平均直径下，与单一颗粒尺寸的情况相比，对于颗粒尺寸分布，涡量沉积是减小的。
A numerical method for predicting the interaction of active, phase changing particles in a shock driven flow is presented in this paper. The Particle-in-Cell (PIC) technique was used to couple particles in a Lagrangian coordinate system with a fluid in an Eulerian coordinate system. The Piecewise Parabolic Method (PPM) hydrodynamics solver was used for solving the conservation equations and was modified with mass, momentum, and energy source terms from the particle phase. The method was implemented in the open source hydrodynamics software FLASH, developed at the University of Chicago. A simple validation of the methods is accomplished by comparing velocity and temperature histories from a single particle simulation with the analytical solution. Furthermore, simple single particle parcel simulations were run at two different sizes to study the effect of particle size on vorticity deposition in a shock-driven multiphase instability. Large particles were found to have lower enstrophy production at early times and higher enstrophy dissipation at late times due to the advection of the particle vorticity source term through the carrier gas. A 2D shock-driven instability of a circular perturbation is studied in simulations and compared to previous experimental data as further validation of the numerical methods. The effect of the particle size distribution and particle evaporation is examined further for this case. The results show that larger particles reduce the vorticity deposition, while particle evaporation increases it. It is also shown that for a distribution of particles sizes the vorticity deposition is decreased compared to single particle size case at the mean diameter.