中国电机工程学报
中國電機工程學報
중국전궤공정학보
ZHONGGUO DIANJI GONGCHENG XUEBAO
2013年
23期
84-91
,共8页
微尺度燃烧%化学熄火%壁面反应%自由基失活%等温壁面
微呎度燃燒%化學熄火%壁麵反應%自由基失活%等溫壁麵
미척도연소%화학식화%벽면반응%자유기실활%등온벽면
micro combustion%chemical quenching%surface reaction%radical quenching%isothermal wall
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。
為瞭攷察等溫壁麵條件下壁麵反應對微通道內氫氣/空氣預混火燄的影響,該文建立瞭攷慮火燄中活性自由基與壁麵相互作用的二維數值模擬程序。計算程序中氣相燃燒採用氫氣詳細化學反應動力學機理,壁麵反應採用改進的氫氣壁麵反應機理,改進的壁麵反應機理包括5箇吸附反應和7箇解附反應。計算結果錶明:等溫壁麵時,壁麵反應會大量消耗壁麵附近的 H、O 及 OH 等活性自由基,導緻貼近壁麵處燃燒反應減弱,靠近壁麵處放熱量減少甚至消失,進而使火燄總的熱量釋放率減少,火燄溫度及傳播速度降低,火燄拉伸減弱。隨著壁麵溫度的升高,壁麵反應作用越顯著。攷慮壁麵反應時,壁麵 H 自由基的覆蓋度最大,對壁麵反應影響最大。
위료고찰등온벽면조건하벽면반응대미통도내경기/공기예혼화염적영향,해문건립료고필화염중활성자유기여벽면상호작용적이유수치모의정서。계산정서중기상연소채용경기상세화학반응동역학궤리,벽면반응채용개진적경기벽면반응궤리,개진적벽면반응궤리포괄5개흡부반응화7개해부반응。계산결과표명:등온벽면시,벽면반응회대량소모벽면부근적 H、O 급 OH 등활성자유기,도치첩근벽면처연소반응감약,고근벽면처방열량감소심지소실,진이사화염총적열량석방솔감소,화염온도급전파속도강저,화염랍신감약。수착벽면온도적승고,벽면반응작용월현저。고필벽면반응시,벽면 H 자유기적복개도최대,대벽면반응영향최대。
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.