合成气/CO_(2)火焰传播过程中辐射再吸收的影响

EFFECTS OF RADIATION REABSORPTION DURING FLAME PROPAGATION OF SYNGAS/CO_(2) MIXTURES

针对生物质制取合成气燃料制备和应用过程中CO_(2)掺混的影响,对合成气/空气/CO_(2)预混火焰中开展数值模拟,通过不同的辐射模型研究辐射再吸收对火焰传播速度的影响。结果表明,辐射再吸收提高了火焰传播速度,最大提升幅度可达11.15%。随当量比增加,辐射再吸收对火焰传播速度的提升幅度从11.15%减小至3.12%,受预热导致的化学效应控制。H自由基在贫燃工况占据主导地位,辐射再吸收通过反应H+O_(2)==O+OH影响火焰传播速度;而富燃工况下,与OH自由基相关的反应H+OH+M=H_(2)O+M是辐射再吸收影响火焰传播速度的主导反应。

Aiming at the effect of CO_(2) mixing in the preparation and application of syngas fuel from biomass,numerical simulations are conducted in syngas/air/CO_(2) flame,the effect of radiation reabsorption on laminar flame speed is studied by different radiation models.Results show that the radiation reabsorption increase the flame speed of syngas/air/CO_(2) mixtures,the relative increment is up to 11.15%.With the increase of equivalence ratio,the increase of flame speed induced by radiation reabsorption effect decrease from 11.15%to 3.12%,which is controlled by the preheat-induced chemical effect.H radicals play the dominant role in the fuel-lean conditions,and the radiation reabsorption effect affects the flame speed through the reaction H+O_(2)==O+OH,while at the fuel-rich conditions,the reaction H+OH+M==H_(2)O+M related to OH radicals is the dominant reaction.