Numerical Simulation Study Of Heat Transfer And Atomization During Immersion Blowing With A Silo Spray Gun

Immersion injection smelting is a common non-ferrous metal smelting technology,which has good advantages in raw material processing,smelting quality and economic benefits.This paper mainly studied the heat transfer of the spray gun and the immersion spray atomization characteristics of the fuel during the immersion smelting process.In this paper,the heat transfer and immersion spray atomization models of Siro spray guns are established for the immersion spray smelting process,and the model is verified.The main contents include:(1)The use of Siro spray gun flow heat transfer model to analyze the effect of gun flow heat transfer under different air flows.(2)The study of the heat transfer mechanism of different cyclone structures under regular heat flow,and the comparison of the synthesis of different cyclones performance.(3)Using the immersion spray atomization model to study and analyze the atomization characteristics of diesel at different air speeds,oil quantities and temperatures.For the flow heat transfer process of the Siro spray gun,the larger the air flow,the better the effect of the heat exchange and the lower the wall temperature.The overall pressure loss of the spray gun is mainly generated at the position of the cyclone.The larger the air flow,the greater the total pressure drop,but the friction coefficient will be decrease.For cyclones with different structures,reducing the pitch multiple and increasing the number of fins can effectively reduce the wall temperature,enhance the convection heat transfer capacity and improve the overall performance.Changing the fin thickness can reduce the wall temperature in a small range,but it has a flow heat transfer effect.The effect is not obvious;increasing the air flow G=79.6350kg/m~2·s,Nusselt number ratio is the smallest,which indicating that increasing the air flow is not sensitive to the improvement of the cyclone convective heat transfer capacity,and can increase the pressure drop ratio and drag coefficient ratio.The wall temperature of the closed cyclone is significantly higher than that of the unclosed cyclone.For the immersion spray atomization process of the Siro spray gun,the penetration data of oil droplets increases first and then stabilizes with the injection time.The greater the velocity of the atomizing air,the greater the increase rate of penetration data,and the greater the penetration data after stabilization.Secondary crushing occurs near the interface of gas-liquid,and after a rapid decrease of about0.004s during the injection process,the total SMD of the oil droplets keep stabile.Let the air velocity bigger,the collision binding capacity become greater and after0.006s,the total SMD are greater.The speed and temperature will be inversely proportional to the SMD of the oil droplets captured on the axial catching surface,and the amount of oil loaded will be reversed.When the space temperature is higher than the diesel evaporating temperature,the higher the temperature,the smaller the mass of the oil droplets captured by the capture surface as the distance from the spray gun mouth,the lower the equilibrium value of the oil droplet mass and the greater the concentration of the axial steam.The purpose of this study is to design the heat transfer model of the spray gun in the actual production process.This model can be used to predict the temperature of the outer wall of the spray gun to a certain extent.Analyzing the flow heat transfer characteristics of cyclones with different structures can help optimize the design of the spray gun to increase the life of spray gun and the running time of furnace.In addition,the research on the characteristics of immersion spray atomization is conducive to improving the smelting quality,enhancing the smelting efficiency and improving the fuel utilization rate.