生物质回转燃烧器燃烧过程的场协同分析

Field synergy analysis of combustion process of biomass rotary burner

针对生物质回转燃烧器燃烧过程,采用非绝热的混合分数-概率密度函数燃烧模型,并考虑对流和辐射传热损失的影响,对该生物质回转燃烧器燃烧过程进行数值仿真和场协同理论分析,研究生物质回转燃烧器的性能和过量空气系数对生物质回转燃烧器燃烧效果的影响。研究结果表明:当过量空气系数λ为1.8~2.4时,燃烧室内温度较高,且生物质回转燃烧器出口处的CO质量分数较低,表明该生物质回转燃烧器的性能较佳;当过量空气系数为1.2时,速度场与焓值梯度场协同角余弦值≥0.8的区域占整个生物质回转燃烧器的比例最大,速度场和焓值梯度场的协同性最佳,生物质回转燃烧器的燃烧性能最好,此时,生物质回转燃烧器燃烧效果处于最佳状态。

Aiming at the combustion process of a kind of biomass rotary burner,a combustion model of nonadiabatic mixed fractional-probability density function was adopted to simulate the combustion process of biomass rotary burner,and field synergy theory analysis was carried out taking into account the convection and radiative heat transfer losses.The effect of properties and excess air coefficient on combustion efficiency of biomass rotary burner was studied.The results show that when the excess air coefficientλis between 1.8-2.4,the mass fraction of CO is lower at the exit of biomass rotary burner,while the combustion temperature is higher at this time and the combustion performance of burner is the best.When the excess air coefficientλis 1.2,the region where the cosine value of the velocity vector and enthalpy gradient angle is bigger than 0.8 has the largest percentage of the whole burner.The velocity field and enthalpy gradient field are in the best synergy and the combustion performance of biomass rotary burner is in the best state.