微通道内甲烷空气预混气的熄火极限

为了研究微尺度催化燃烧可燃极限的变化规律,使用计算流体软件FLUENT和化学动力学软件DETCHEM对甲烷空气预混气体在微通道内催化燃烧进行了数值模拟。计算结果表明,微通道的导热壁对火焰的稳定性有重要的影响。较低的流速造成燃气在微通道内停留的时间过长,大量的热量通过导热壁散失到环境中导致熄火;较高的流速使燃烧区域往下游移动,导致吹熄。熄火特征与导热壁面温度以及铂和氧的表面覆盖率之比有关。

Extinction limits of CH4/air premixed combustion in a microchannel

The commercial fluid dynamics software FLUENT was used with the chemistry software DETCHEM to simulate the catalytic combustion of CH4 and air in a microchannel to study the extinction limits of micro-scale catalytic combustion.The results show that the microchannel conducting wall significantly affects the flame stability.Low flow rates result in long staying times of the combustion gas in the microchannel with large amounts of heat dissipated through the conducting wall,which causes extinction.High flow rates move the reaction zone downstream,which causes blowout.The results also show that extinction is affected by the conducting wall temperature and the ratio of the platinum covering rate to the oxygen covering rate.