多孔介质内低热值气体燃烧及传热数值模拟

以一个简化的氧化铝(Al2O3)堆积小球多孔介质燃烧器为模拟对象,使用计算流体力学(CFD)方法对低热值气体燃烧进行模拟研究.考虑气体的湍流扩散和气固间的对流换热及固体间的辐射和导热换热,通过研究多孔介质内的压力分布、速度分布、温度分布及组分分布,对多孔介质内的总的热流密度及辐射热流密度进行对比分析,揭示燃烧器内不同轴向位置的燃烧及换热规律.结果表明,低热值气体在氧化铝(Al2O3)堆积小球多孔介质燃烧器内燃烧时火焰面前沿气固温差大于火焰面后气固温差.火焰面前沿固体温度高于气体温度,热量由固体传向气体,对流换热强度较大;火焰面后沿气体温度高于固体温度,热量由气体传向固体,对流换热强度较小.

Numerical simulation of low calorific gas combustion and heat transfer in porous media

Computational fluid dynamics (CFD) was used to study low calorific gases combustion and heat transfer in a 2 D alumina (Al2O3) particle packed bed porous media burner. With considering turbulence and diffusion of gas, convection between gas and solid, radiation and conduction between solid and solid, the distributions of pressure, velocity, temperature of gas and solid, mole fraction of premixed gas in the porous media were simulated. Based on the investigation, the total heat flux and radiation heat flux at different axe location were compared. The simulation results show that the temperature difference between gas and solids in front of combustion fronts is larger than that at back of combustion fronts. Heat transfer is more intense in front of combustion fronts. Solids have higher temperature than gas thus the heat is transferred from solid to gas. Behind the combustion fronts, the heat transfer intensity is relative low and the gas temperature is higher than solids'.