Numerical Simulation Of Flow And Heat Transfer During Methane Immersion Combustion In A Molten Pool

In the metallurgical process,in order to strengthen the heat transfer and maintain the temperature in the molten pool,it is often necessary to directly pass fuel and air into the molten pool,and the flow of high temperature flue gas bubbles between the metal melt after fuel combustion directly affects the reaction rate in the metallurgical process.The process of combustion,expansion,breakage and movement of high temperature flue gas bubbles is very complicated,which involves not only heat and mass transfer,momentum transfer,but also two-phase flow phenomenon.However,at present,most of the relevant studies on molten pool melting are carried out under cold conditions,and the flow,deformation and heat transfer of high temperature flue gas bubbles after immersion combustion have not been reported.Therefore,the direct immersion combustion phenomenon is studied theoretically in the background of molten pool melting.The main research contents are as follows:(1)Using CFD analysis under different oxygen concentration in the process of submerged combustion of methane,the results show that the combustion process is intermittent,bubbles in the pipe after burning out of spray gun,and with the increase of oxygen concentration of temperature in the bubble is increased from 2500 k to 3000k,the bubbles of combustion for nozzle pressure distribution and the shape of the bubble has obvious influence.(2)Two dimensional simulation of the continuous injection process of two spray guns with different spacing and melt with different viscosity was carried out.The results show that with the increase of spacing,there are three different bubble flow states,and the turbulent kinetic energy increases from 0.015m²/s²to 0.04m²/s².Due to the influence of bubble flow pattern,the temperature distribution in the flow field is also slightly different,but the average temperature has not been significantly increased.The influence of fluid viscosity on bubble flow pattern and streamline is small.(3)Vortexes are widely distributed in the molten pool melting process,especially in the case that there are a large number of different sizes and intensities in the turbulent process.Accurate identification of the vortex structure is of great significance for understanding the flow mechanism and solving the problems encountered in the turbulent process.In this paper,Tecplot and Matlab were used to compare the vortex structures obtained by different vorticity processing methods in 3D model.It is found that the vortex structures obtained by Q criterion are similar to those obtained by?₂method and?method,while the former method can characterize both strong and weak vortexes.In this paper,the simulation study on the process of methane submersion combustion has been carried out,which strengthens the understanding of the submersion combustion,and is of great significance to improve the melting process of molten pool and reduce the loss of materials.