A multicomponent real-fluid fully compressible four-equation model for two-phase flow with phase change
A multicomponent real-fluid fully compressible four-equation model for two-phase flow with phase change
复制标题
具有相变的两相流多组分真实流体完全可压缩四方程模型
DOI：
10.1063/1.5065781
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发表时间：
2019
影响因子：
4.6
通讯作者：
R. Lugo
中科院分区：
文献类型：
--
作者：
Ping Yi;Songzhi Yang;C. Habchi;R. Lugo
提出了一种多组分两相流的完全可压缩四方程模型，并结合了实流体相平衡求解器。在力学和热平衡假设下，它由两个质量、一个动量和一个能量平衡方程组成。考虑了液相和气相的多组分特性。热力学性质采用复合状态方程（EoS）计算，其中每个相在其凸度范围内遵循自己的Peng-Robinson (PR) EoS，并且两相混合物与一组代数平衡约束联系起来。这种复合声速方程避免了两相混合物声区速度复杂的缺点。相变计算使用相平衡求解器，其中相稳定性是由切平面距离法检查；采用等温等压等能闪法测定相变。该四方程模型已在内部IFP-C3D软件中实现。对四方程模型的预测结果、闪沸情况下的实验测量结果和已有的数值结果进行了广泛的比较，得到了很好的一致性。结果表明，该四方程模型能较好地模拟多组分两相流的相变，并能较好地反映多组分两相流的真实流体行为。最后，应用该验证模型研究了正十二烷/氮混合物在一维激波和双膨胀管中的行为。揭示了复杂的波型，揭示了PR - EoS中溶解氮和体积平移对波演化的影响。最后对三维跨临界燃油喷射进行了仿真，以突出所提出的四方程模型在多维流动中的性能。
A fully compressible four-equation model for multicomponent two-phase flow coupled with a real-fluid phase equilibrium-solver is suggested. It is composed of two mass, one momentum, and one energy balance equations under the mechanical and thermal equilibrium assumptions. The multicomponent characteristics in both liquid and gas phases are considered. The thermodynamic properties are computed using a composite equation of state (EoS), in which each phase follows its own Peng-Robinson (PR) EoS in its range of convexity, and the two-phase mixtures are connected with a set of algebraic equilibrium constraints. The drawback of complex speed of the sound region for the two-phase mixture is avoided using this composite EoS. The phase change is computed using a phase equilibrium-solver, in which the phase stability is examined by the Tangent Plane Distance approach; an isoenergetic-isochoric flash including an isothermal-isobaric flash is applied to determine the phase change. This four-equation model has been implemented into an in-house IFP-C3D software. Extensive comparisons between the four-equation model predictions, experimental measurements in flash boiling cases, and available numerical results were carried out, and good agreements have been obtained. The results demonstrated that this four-equation model can simulate the phase change and capture most real-fluid behaviors for multicomponent two-phase flows. Finally, this validated model was applied to investigate the behaviors of n-dodecane/nitrogen mixtures in one-dimensional shock and double-expansion tubes. The complex wave patterns were unraveled, and the effects of dissolved nitrogen and the volume translation in PR EoS on the wave evolutions were revealed. A three-dimensional transcritical fuel injection is finally simulated to highlight the performance of the proposed four-equation model for multidimensional flows.