管内螺旋涡流中环状流形成及稳定机理

Annular flow is characterized by low flow resistance and high heat transfer coefficient. Its existence can reduce the energy consumption in gas-liquid transportation and enhance the heat transfer. The present project is aimed to establish the annular flow within a broader hydrodynamic range on the basis of the density difference between gas and liquid and by promoting the redistribution of the gas-liquid interface with swirling flow and thus changing the transition boundaries of the flow regime. Through analytical, numerical and experimental methods, the project is to propose a dynamic model of the gas-liquid swirling flow and a mathematic model of the interfacial waves in the annular two-phase flow, and to illustrate the formation mechanisms and the dynamic conditions of the annular flow in gas-liquid two phase swirling flow and for different inlet flow regimes. Studies on the stability mechanism and the dynamic conditions of interfacial wave in annular flow will also be included. A through knowledge of the flow regime transition, its quantitative prediction, the stability of interfacial wave and flow resistance will be obtained. Research results will benefit the industrial applications of the annular flow by reducing fluid resistance, increasing heat transfer efficient and improving flow safety. Meanwhile, it provides advanced model, experimental data and fundamental laws for the construction of theories about gas-liquid two phase swirling flow.

环状流动具有较低的流动阻力和较高的传热系数，可以降低气液输送能耗、提高换热性能。基于气液两相密度差这一基本物理特性，本项目提出了利用螺旋涡流促使气液相界面重新分布，改变气液两相流流型转变界限，在更宽广的流动范围形成环状流这一创新思路。通过理论建模、数值模拟、机理实验相结合的方法，构建气液两相螺旋涡流动力学模型和螺旋涡流作用下的环状流界面波数理模型，阐明不同来流流型条件下气液两相螺旋涡流中环状流形成的机理与动力学条件，环状流界面波稳定机理和动力学条件，掌握螺旋涡流作用下的流型转变、环状流界面波稳定性、流动阻力等规律和定量预测方法。研究成果将为应用环状流动技术实现降低流动阻力、增强换热效率、提高流动安全等工业应用提供理论基础；为构建气液螺旋涡流基础理论提供先进模型、基础数据和基本规律。

环状流动具有较低的流动阻力、较高的传热系数、较好的气液分离性，可以降低气液输送能耗、提高换热性能和气液分离效率，在物料输送、强化换热、气液分离、流动安全等工业领域得到了广泛应用。基于气液两相密度差这一基本物理特性，本项目提出了利用螺旋涡流促使气液相界面重新分布，在更宽广的流动范围形成环状流的创新思路。通过机理实验、理论建模和数值模拟相结合的研究方法，提出了高含气率气液两相流测量新方法，系统研究了螺旋涡流及非螺旋涡流作用下气液两相流的关键基础科学问题，揭示了大振幅界面波及液滴夹带机理，构建了气液两相螺旋涡流动力学模型和螺旋涡流作用下环状流界面波数理模型，阐明了不同来流流型条件下气液两相螺旋涡流中环状流形成的机理与动力学条件，揭示了环状流液膜失稳的动力学机理，掌握了螺旋涡流作用下的流型转变、环状流界面波稳定性、流动阻力等规律和定量预测方法。研究成果将为应用环状流动技术实现降低流动阻力、增强换热效率、提高流动安全等工业应用提供理论基础；为构建气液螺旋涡流基础理论提供先进模型、基础数据和基本规律。