高压下CO2稀释的CO/H2/Air火焰贫可燃极限处的辐射重吸收效应的数值研究

本文分别采用考虑辐射重吸收的谱带辐射（SNBCK）模型及未考虑辐射重吸收的光学薄辐射（OPT）模型,对0.1～4 MPa,CO₂稀释比为0%和20%的一维预混层流合成气/空气火焰进行数值分析,研究辐射重吸收效应对可燃极限及极限处的火焰传播速度和温度的影响。结果表明,辐射重吸收效应能有效拓宽贫可燃极限,提高燃料中CO₂比例或提高CO/H₂比例都会加剧上述效果。辐射重吸收效应随压力增大而逐渐增强,并造成可燃极限处最大火焰温度随压力先增加后减小,在1 MPa左右达到峰值。

Numerical Investigation of Radiation Re-Absorption Influences on Flame Behaviors of CO/H2/Air Mixtures With CO2 Diluted Near Lean Flammability Limits at High Pressures

One-dimensional laminar premixed flames for CO/H₂/air mixtures were investigated numerically for a wide range of pressures with different CO₂ diluted ratios.Re-absorption-included radiation model called statistical narrow-band correlated-k（SNBCK）model and re-absorption-excluded radiation model called optically thin（OPT）model were used respectively in order to assess the impacts of re-absorption on flame behaviors near lean flammability limits.Results revealed that re-absorption extended lean flammability limits and these effects increased with increasing CO2 addition or ratios of CO/H₂.Effect of re-absorption strengthened as pressures increased.The maximum flames temperature at lean flammability limits increased first and then decreased with a peak value at near 10atm as pressures increased.