为了考察等温壁面条件下壁面反应对微通道内氢气/空气预混火焰的影响,该文建立了考虑火焰中活性自由基与壁面相互作用的二维数值模拟程序。计算程序中气相燃烧采用氢气详细化学反应动力学机理,壁面反应采用改进的氢气壁面反应机理,改进的壁面反应机理包括5个吸附反应和7个解附反应。计算结果表明:等温壁面时,壁面反应会大量消耗壁面附近的H、O及OH等活性自由基,导致贴近壁面处燃烧反应减弱,靠近壁面处放热量减少甚至消失,进而使火焰总的热量释放率减少,火焰温度及传播速度降低,火焰拉伸减弱。随着壁面温度的升高,壁面反应作用越显著。考虑壁面反应时,壁面H自由基的覆盖度最大,对壁面反应影响最大。
In order to investigate the effect of surface reaction on H2/air premixed combustion in micro channel under the wall conditions of isothermal,a 2-D numerical simulation program with consideration of the interaction between active radicals and wall was established.The detailed H2 chemical kinetics was used in gas combustion,and an improved surface reaction mechanism which includes 5 adsorption reactions and 7 desorption reactions was adopted for heterogeneous reaction simulation.The simulation results show that,under the isothermal wall condition,active radicals including H,O and OH near surface are largely consumed by surface reaction,which will cause the decrease of combustion reactions,and consequently the reduction of heat release rate and flame stretch,and the decrease of flame temperature and propagation velocity.Furthermore,the effect of surface reaction becomes more obvious with the increase of surface temperature.For surface reaction,coverage of H active radical which has the biggest effect on surface reaction is largest.