Radical quenching of metal wall surface in a methane-air premixed flame
Radical quenching of metal wall surface in a methane-air premixed flame
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DOI：
10.1016/j.combustflame.2015.07.043
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发表时间：
2015-10
影响因子：
4.4
通讯作者：
Y. Saiki;Yong Fan;Yuji Suzuki
中科院分区：
文献类型：
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作者：
Y. Saiki;Yong Fan;Yuji Suzuki
为了量化金属壁面的化学淬火效应，研究了窄缝石英板通道内甲烷-空气预混火焰的形成。选用不锈钢321(SUS321)和Inconel600作为表面材料，具有较高的耐氧化性和耐热性。利用真空电弧等离子体枪在石英片上沉积了SuS321和Inconel600薄膜，实现了不同表面反应的等效热边界条件。此外，利用原子层沉积(ALD)和溅射技术制备了两种类型的氧化铝薄膜，以探索其表面粗糙度效应。用微观的OH-PLIF和详细化学的数值模拟研究了近壁火焰的结构。当壁面温度Tw≧为1073℃时，SuS321/Inconel600表面附近的OH浓度明显低于石英表面附近的浓度。根据PLIF数据，估算了SUS321/Inconel600和石英表面与自由基吸附有关的初始粘着系数S0分别为0.1和0.01，表明这些金属表面具有较强的自由基猝灭效应。而溅射Al_2O_3表面附近的OH分布与AlD-Al_2O_3表面附近的一致，具有较大的粗糙度。这意味着自由基吸附与表面粗糙度无关。
In order to quantify chemical quenching effect of metal wall surfaces, a methane-air premixed flame formed in narrow quartz plate channels is investigated. Stainless steel321 (SUS321) and Inconel600 are chosen as the surface materials for their high oxidation/heat resistivity. Thin films of SUS321 and Inconel600 are deposited on the quartz plates using a vacuum arc plasma gun to realize equivalent thermal boundary condition with different surface reactions. In addition, two types of alumina thin films are prepared using atomic layer deposition (ALD) and sputtering techniques to explore the surface roughness effect. Microscopic OH-PLIF and numerical simulation with detailed chemistry are employed to examine the near-wall flame structures. When the wall temperatureTw≧ 1073 K, OH concentrations near the SUS321/Inconel600 surfaces are significantly lower than that near the quartz surface. Based on the PLIF data, the initial sticking coefficientS0associated with radical adsorption is estimated to be 0.1 and 0.01 for the SUS321/Inconel600 and quartz surfaces, respectively, indicating stronger radical quenching effect on these metal surfaces. On the other hand, OH profile near the sputtered-alumina surface, which has larger roughness, is in good accordance with that near the ALD-alumina surface. This implies that the radical adsorption is independent on surface roughness.