Low-concentration methane(LCM) has been one of the biggest difficulties in using coal mine methane.And previous studies found that premixed combustion in porous media is an effective method of low calorific gas utiliz...Low-concentration methane(LCM) has been one of the biggest difficulties in using coal mine methane.And previous studies found that premixed combustion in porous media is an effective method of low calorific gas utilization. This paper studied the combustion of LCM in a divergent porous medium burner(DPMB) by using computational fluid dynamics(CFD), and investigated the effect of gas initial temperature on combustion characteristic, the distribution of temperature and pollutant at different equivalence ratios in detail. Besides, the comparison of divergent and cylindrical burners was also performed in this paper. The results show that: the peak temperature in DPMB increases as the increasing of equivalence ratio, which is also suitable for the outlet NO discharge; the linear correlation is also discovered between peak temperature and equivalence ratios; NO emission at the initial temperature of 525 K is 5.64 times,larger than NO emission at the initial temperature of 300 K. Thus, it is preferable to balance the effect of thermal efficiency and environment simultaneously when determining the optimal initial temperature range. The working parameter limits of divergent burner are wider than that of cylindrical one which contributes to reducing the influence of LCM concentration and volume fluctuation on combustion.展开更多
基金the supports by the National Basic Research Program of China (No. 2011CB201205)the National Natural Science Foundation of China (No. 51204169)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China (No. 20110095120017)the Fund of China Postdoctoral Science Foundation of China (No. 20110491482)
文摘Low-concentration methane(LCM) has been one of the biggest difficulties in using coal mine methane.And previous studies found that premixed combustion in porous media is an effective method of low calorific gas utilization. This paper studied the combustion of LCM in a divergent porous medium burner(DPMB) by using computational fluid dynamics(CFD), and investigated the effect of gas initial temperature on combustion characteristic, the distribution of temperature and pollutant at different equivalence ratios in detail. Besides, the comparison of divergent and cylindrical burners was also performed in this paper. The results show that: the peak temperature in DPMB increases as the increasing of equivalence ratio, which is also suitable for the outlet NO discharge; the linear correlation is also discovered between peak temperature and equivalence ratios; NO emission at the initial temperature of 525 K is 5.64 times,larger than NO emission at the initial temperature of 300 K. Thus, it is preferable to balance the effect of thermal efficiency and environment simultaneously when determining the optimal initial temperature range. The working parameter limits of divergent burner are wider than that of cylindrical one which contributes to reducing the influence of LCM concentration and volume fluctuation on combustion.
