水平管气液两相分层流界面剪切预测研究进展

Progress of interfacial shear stress in the gas-liquid stratified flow in horizontal pipes

水平管气液两相分层流虽流型简单,但由于界面存在复杂的动量和能量传递,分层流的界面剪切预测至今没有一致的结论。本文从理论模型、实验模型、数值计算3个角度出发,详细阐述水平管气液两相分层流界面剪切预测的研究现状,得出不同研究方法的优势和缺陷。针对3种研究方法,指出理论模型通过模型简化和经验关联式来建立封闭模型,实验模型则在封闭关系上修正经验关联式,但由于简化假设和实验条件的限制,使得这两种研究方法对界面剪切应力的预测具有一定的局限性;数值计算能够弥补机理模型在流场细节等方面的不足,但能够提供界面剪切预测或封闭关系的工作很少。此外,对比了5种不同形式的已有模型对气液两相分层流持液率和压降预测的结果。最后展望了水平管气液两相分层流界面剪切预测的研究趋势,提出理论和实验研究需要提出更详细的局部模型,并考虑工程实际工况进行研究,发展针对气液界面计算的新方法,并为分层流提供封闭关系则是数值计算研究面临的挑战。

The gas-liquid two-phase stratified flow has complex momentum and energy transmission phenomena at interface,although its pattern is simple. There are still no unified conclusions for interfacial shear stress in stratified flow. Current progress of interfacial shear stress in horizontal pipes were elaborated by theoretical models,experimental models and numerical simulations. As for theoretical models,closure models were established by models simplification and empirical correlations. Empirical correlations were corrected with closure relations in experiments. Due to simplifying assumptions and experimental conditions,there are some limitations in predicting the interfacial shear stress with theoretical and experimental ways. The detailed flow fields were studied by numerical simulations,but closure relations have been less obtained so far. Five existing models are compared according to liquid holdup and pressure drop. The future research trends of gas-liquid two-phase stratified flow interfacial shear stress in horizontal pipes were further discussed. More detailed local models are needed to be proposed and engineering practice should be taken into account. It is necessary to develop new methods of gas-liquid interface calculations and closure relations for numerical simulations.