Numerical Simulation Of High Temperature Air Combustion In Annular Furnace

High temperature air combustion (HTAC) is one of the most important innovations in the field of combustion and thermal process. The study of the high temperature combustion process and its thermal characteristics in the industry furnaces has momentous theoretical and practical significance for the further development and application of high temperature combustion technology.According to the features of high temperature combustion process, theoretical analysis and three-dimension combustion model in the industry annular heating furnace are presented in the thesis. The fuel is nature gas, and the high temperature combustion characteristics in the industry annular heating furnace are researched in detail. The distributions of temperature, velocity and fuel concentration in the annular heating furnace are found out, and the factors, including fuel mass flux and the distance between fuel inlet and air inlet, are also researched. Further more, the influence of exchange process on the combustion in the furnace is studied, and the transient combustion characteristics in the annular heating furnace are researched.The results show that both combustion and flow in the annular furnace have periodicity, and methane combustion efficiency is high when inner burner works. Alternating array of gas burners may improve combustion efficiency and it has important influence on the thermal characteristics. Distribution of flow velocity and oxygen concentration is higher in the middle than that in the both sides along the altitudinal direction whether inner burner or outer burner works.The influence of Natural gas mass flow is most important on the thermal characteristics in the annular furnace. When methane mass flow increases, the temperature in the annular furnace increases, and temperature distribution in the annular furnace is more uniform, but methane combustion efficiency decreases. When the distance between air spout and methane spout decreases, methane can catch fire in the nearer and its combustion efficiency increases. The temperature distribution in the annular furnace is more uniform. When gas burners are alternating arrayed and periodically work, average temperature in the annular furnace is uniform. It is suitable for keeping the temperature uniform of the material in the furnace. The results have reference meaning for the design and operation of annular furnace.