Turbulence Behavior below an Gas-Liquid Interface and Effects of Interfacial Waves in a Horizontal Stratified Flow.

采用实验和数值分析相结合的方法，研究了水平分层流动中空气-水界面的动量传递。当液体雷诺数为1200时，光滑界面表现为与固壁相似，而波状界面表现为与固壁不同。当雷诺数为11500时，界面附近的湍流与壁面湍流完全不同。在数值分析中，对k-epsilon模型进行了修正，以满足湍流能量、耗散率和雷诺应力对界面的渐近行为。修正的k-epsilon模型可以定量预测光滑界面下的湍流行为。研究了水平矩形通道中蒸汽-过冷水界面直接接触凝结换热。采用三种模型对界面换热系数进行了预测。热传导模型提供了最低的换热极限。与壁面k-epsilon模型相比，修正的K-epsilon模型能较好地模拟近界面湍流量的变化，与光滑界面下的实验结果吻合较好。通过在表面更新模型中引入界面波效应，定性地预测了有界面波的凝结换热。

Momentum transfer across an air-water interface was studied in a horizontal stratified flow through experimental and numerical analysis. When the liquid Reynolds number equaled to 1200, the smooth interface behaved similar to a solid wall, while the wavy interface behaved different from a solid wall. When the Reynolds number was 11500, turbulence near the interface was completely different from the wall turbulence. In numerical analysis, the k-epsilon model was modified to satisfy asymptotic behavior of turbulent energy, dissipation rate and Reynolds stress to the interface. The modified k-epsilon model could quantitatively predict the turbulence behavior below the smooth interface.Heat transfer by direct contact condensation at a steam-subcooled water interface was investigated in a horizontal rectangular channel. Three types of models were used to predict the heat transfer coefficients at the interface. The heat conduction model provided the lowest limit of heat transfer. The modified K-epsilon model, which could simulate the near-interface variation of the turbulence quantities, showed the more improved prediction compared with the wall k-epsilon model and agrees with the experimental results with smooth interfaces. The condensation heat transfer with interfacial waves were predicted qualitatively by introducing the interfacial wave effect into the surface renewal model.