为实现多组分复杂流体流动与扩散耦合过程的准确预测,提出一种耦合多组分Shan-Chen格子玻尔兹曼法(lattice Boltzmann method,LBM)、Maxwell-Stefan扩散通量方程及4参数(临界温度、临界压力、偏心因子和体积修正因子)Peng-Robinson状态...为实现多组分复杂流体流动与扩散耦合过程的准确预测,提出一种耦合多组分Shan-Chen格子玻尔兹曼法(lattice Boltzmann method,LBM)、Maxwell-Stefan扩散通量方程及4参数(临界温度、临界压力、偏心因子和体积修正因子)Peng-Robinson状态方程(equation of state,EOS)的多组分流体流动与扩散耦合模型(equation of state Maxwell-Stefan force model,EOS-MS模型).通过Peng-Robinson EOS计算混合流体整体的流体间作用力,结合多组分LBM中流体间作用力与压力的关系,构建组分流速与流体间作用力的关联,并代入Maxwell-Stefan方程,推导得到各组分受力的代数方程组.利用精确差分法(exact difference method,EDM)将计算得到的组分间作用力引入多组分LBM.分别模拟甲烷、乙烷纯物质及其混合物的气液两相共存问题,计算结果与标准参考数据及逸度平衡法的计算结果一致,验证了模型在预测混合流体热力学平衡态方面的准确性.通过模拟氢气、氮气和二氧化碳的三元扩散动态过程,发现模型结果与有限体积法预测高度吻合,并成功复现了多组分流体中逆扩散等实际扩散现象,证明模型在多组分流体流动与扩散耦合模拟中的有效性.本研究构建的EoS-MS力模型可准确预测多组分流动与扩散耦合过程,避免了在组分受力计算中引入人为假设带来的误差,为解决地热资源利用等领域中存在的多组分复杂流动问题提供了新方法.展开更多
The calculated fluid dynamics (CFD) model of the two-phase flow field in the directed trapezoid spray tray (CTST-8) was established with the volume of fluid (VOF)method.The physical model was established with the soft...The calculated fluid dynamics (CFD) model of the two-phase flow field in the directed trapezoid spray tray (CTST-8) was established with the volume of fluid (VOF)method.The physical model was established with the software Gambit,and the grid was adapted by the gradient of velocity.Under the condition that the gas velocity in the tray hole was kept at 8.4 m·s-1 and clear liquid height was kept at 25mm,calculation was carried out with commercial software FLUENT 6.1.The results showed the three-dimensional characteristics,and displayed the detailed information of the flow field in the cover such as the distribution of phase volume fraction,velocity field,and pressure field.The pressure values in the cover and the relative liquid-liftup of a single-cover acquired by the simulation were in good agreement with the experimental results.The model had a high degree of accuracy,and could be used to predict the two-phase flow field in CTST-8.展开更多
文摘为实现多组分复杂流体流动与扩散耦合过程的准确预测,提出一种耦合多组分Shan-Chen格子玻尔兹曼法(lattice Boltzmann method,LBM)、Maxwell-Stefan扩散通量方程及4参数(临界温度、临界压力、偏心因子和体积修正因子)Peng-Robinson状态方程(equation of state,EOS)的多组分流体流动与扩散耦合模型(equation of state Maxwell-Stefan force model,EOS-MS模型).通过Peng-Robinson EOS计算混合流体整体的流体间作用力,结合多组分LBM中流体间作用力与压力的关系,构建组分流速与流体间作用力的关联,并代入Maxwell-Stefan方程,推导得到各组分受力的代数方程组.利用精确差分法(exact difference method,EDM)将计算得到的组分间作用力引入多组分LBM.分别模拟甲烷、乙烷纯物质及其混合物的气液两相共存问题,计算结果与标准参考数据及逸度平衡法的计算结果一致,验证了模型在预测混合流体热力学平衡态方面的准确性.通过模拟氢气、氮气和二氧化碳的三元扩散动态过程,发现模型结果与有限体积法预测高度吻合,并成功复现了多组分流体中逆扩散等实际扩散现象,证明模型在多组分流体流动与扩散耦合模拟中的有效性.本研究构建的EoS-MS力模型可准确预测多组分流动与扩散耦合过程,避免了在组分受力计算中引入人为假设带来的误差,为解决地热资源利用等领域中存在的多组分复杂流动问题提供了新方法.
文摘The calculated fluid dynamics (CFD) model of the two-phase flow field in the directed trapezoid spray tray (CTST-8) was established with the volume of fluid (VOF)method.The physical model was established with the software Gambit,and the grid was adapted by the gradient of velocity.Under the condition that the gas velocity in the tray hole was kept at 8.4 m·s-1 and clear liquid height was kept at 25mm,calculation was carried out with commercial software FLUENT 6.1.The results showed the three-dimensional characteristics,and displayed the detailed information of the flow field in the cover such as the distribution of phase volume fraction,velocity field,and pressure field.The pressure values in the cover and the relative liquid-liftup of a single-cover acquired by the simulation were in good agreement with the experimental results.The model had a high degree of accuracy,and could be used to predict the two-phase flow field in CTST-8.
