Simulation Of The Gas-Liquid Mixing Process In Vertical Circular Pipe

Gas-liquid two phase flow in vertical circular pipe widely exists in many industrial fields, such as nuclear power engineering and aerospace. The shape of gas-liquid mixing chamber in atomizing device usually in circular tube structure, gas phase and liquid phase flow into the mixing chamber respectively by different inlet, and start to formation continuous bubbles, with different conditions the flow structure will be different, sometimes will be the bubblely flow, sometimes will be slug flow or annular flow regime, and at last spray out and atomization achieved. The flow pattern formation, and the formation of bubble and transition of flow pattern in the mixing chamber have effect on atomization of bubble atomizing device, in order to explore the characteristics of two-phase flow in vertical pipe, In this paper the author use the FLUENT simulation software to simulate gas-liquid mixing process in vertical circular pipe.According to the structure characteristics and the operating condition of atomizing device, the simulation calculation model was built. The author have complete the division of the grid and have determined the initial conditions and boundary conditions, using the simulation model in literature and the experimental results to verify the reliability of the model.Firstly, based on the characteristics of the circular pipe, the author have simulated the bubble formation process in the inlet hole. Analysis of the bubble formation process by variating characteristics of gas and liquid, and have analysed the influence of gas-liquid two-phase flow pattern, static contact angle and liquid properties parameters on bubble formation time and the bubble volume, obtained the law of changes in the characteristics of bubble formation.Secondly, the change in vertical pipe of gas-liquid two-phase flow pattern and the flow pattern have studied, analysed the influence of the inner diameter of the circular pipe, liquid viscosity, liquid density and surface tension on two-phase flow. The results of the study show that, in certain conditions the mass flow rate is the main factor affecting the flow pattern.Finally, the pulsation of the gas-liquid two-phase flow parameters under different flow patterns are analyzed. The paper have studied the void fraction of different flow pattern at different section, and have annlysed fluctuation intensity of flow parameters in different flow patterns. The results show that under different flow void ratio changes with the time difference characteristics significantly; fluctuation intensity of gas-liquid two-phase flow parameters like bubble flow and annular flow regimes under the smaller than the other.The study provides the basis for the structural design and selection of operating results for the mixing chamber of bubble atomizing device.