Numerical Simulation of the Effect of Burner Jets Parameters on High Temperature Air Combustion

Based on the high temperature air combustion(HTAC),the numerical simulation was carried out on the high temperature air combustion of coal gas in an industrial furnace with a multi-jet burner.The furnace was a rectangular chamber of 800 mm×800 mm×1 400 mm.The burner was made up of a circular fuel jet of a diameter of 10 mm at the center and 5 circular air jets equably distributed around the fuel jet with different straddle angles.The fuel jet deviated from the air jet with a inclined angle,α.PDF(Probability Density Function) combustion model based on a β function was selected to simulate the gas combustion combined with the standard k-e model to simulate the flow field.The radiation was simulated by a discrete ordinates method.The NOx emission was simulated by thermal NOx model.The effect of jet parameters,i.e.,the velocity ratio of fuel jet and air jet and the fuel jet inclined angle on the combustion characteristics was discussed.The simulated results show that the jet parameters change the recirculation of flue gas in the chamber leading to different mixing of the fuel,air and hot flue gas which determine the local temperature,oxygen concentration and NOx production.As the velocity ratio of fuel jet and air jet and the fuel jet inclined angle increase,the flue gas recirculation enhances and the low oxygen zone enlarges.The maximum and mean temperature both decrease and NOx emission decreases.The results provide a reference for the design of industrial furnace burner.