Numerical Simulation Of Atomization And Combustion Characteristics Of Tubular Heating Furnace Nozzles

The fuel used in refinery tubular furnaces include fuel oil and gas.In the combustion of fuel oil,the fuel and the oxidant belong to different states and are therefore heterogeneous combustion.In general,when a fuel oil is burned,its chemical reaction rate is much faster than the rate at which the two-phase fluid diffuses and mixes.In order to facilitate the ignition,steady combustion and burnout of the fuel oil,the fuel oil is atomized into fine droplets by the atomizer before being sent to the furnace through the oil supply system.The effect of atomization has a decisive influence on the combustion process of fuel oil.The research on the atomization process of fuel oil plays an important role in the research of tubular heating furnace.In this paper,CFD analysis software is used to analyze the fuel oil atomization and combustion process under given working conditions,and to explore the influence of nozzle structure parameters and operating parameters on the atomization process.The results show that for the nozzle mixing chamber under the design parameters of this paper,the stabilized fuel component mass fraction is 15%,the speed is 20m/s,and the temperature is 460 K.In the nozzle structure parameters,the position and angle of the water vapor conduit have a great influence on the atomization process.The position of the water vapor conduit is the boundary line between different states of the mixing chamber flow field.The flow is unstable near the boundary line and below.The kinetic energy and heat exchange are relatively intense.Above the boundary line,the working fluid gradually enters a steady state with constant speed and temperature.The angle of the water vapor conduit has a great influence on the atomization process.When the angle is less than 60 °,the component collision is insufficient,and the atomization effect is not good.When the angle is greater than120° and gradually increases,water vapor may flow into the fuel oil conduit,endangering safe production.The diameter of the mixing chamber orifice has an influence on the turbulent flow energy in the mixing chamber,and has a great influence on the outlet velocity of the orifice.In the nozzle operating parameters,the small range change of the fuel oil inlet speed has little effect on the overall flow field distribution characteristics of the mixing chamber.The production requirements and production costs should be considered comprehensively todetermine the matching velocity of water vapor and fuel Oil.