Three-dimensional direct numerical simulations of turbulent catalytic and gas-phase H₂/air combustion at a fuel-lean equivalence ratio $\phi =0.18$ were performed in platinum-coated planar channels at two industrially-relevant flow conditions (inlet friction Reynolds numbers Re_τ= 182 and 385) using detailed hetero-/homogeneous chemical reaction mechanisms. The preferential diffusion of hydrogen and oxygen, which was responsible for creating significantly higher surface equivalence ratios φ_w compared to the bulk gas-phase φ, was appreciably suppressed by turbulence at Re_τ= 385. The higher turbulence intensity at this Re_τ resulted in larger near-wall hydrogen excess that in turn yielded shorter homogeneous ignition distances compared to the lower Re_τ case. Gas-phase ignition proceeded from isolated ignition kernels that subsequently formed axially elongated flames confined close to the catalytic walls. The coupling of catalytic and gas-phase chemistry inhibited homogeneous ignition, since at the vicinity of the ignition kernels the OH, H and O radical fluxes to the underlying catalytic wall were net-adsorptive and furthermore hydrogen was depleted by the catalytic reactions. The flame topology included alternating vigorously-burning and extinguished elongated streamwise stripes at $R{e}_{\tau }=182$ or islands at $R{e}_{\tau }=385$. The extinguished gas-phase reaction zones at $R{e}_{\tau }=385$ were characterized by underlying intense catalytic reaction rates. The flame topology and spatiotemporal correlation of the isolated burning and extinguished gaseous zones indicated that significant surface temperature non-uniformities could be obtained in practical catalytic reactors.

贫燃当量比的湍流催化和气相H ₂ /空气燃烧的三维直接数值模拟$\phi =0.18$在两个工业相关的流动条件在铂涂覆的平坦通道进行（入口摩擦雷诺数重新_τ使用详述的杂/均相化学反应机制= 182和385）。氢气和氧气的选择性扩散，这是负责创建显著更高的表面的当量比φ_瓦特相比本体气相φ，被明显地由在湍流抑制再_τ = 385。在此较高的湍流强度重新_τ导致较大的近壁的氢气过量，这又产生了更短的均匀的点火距离比下再_τ案件。气相点火从孤立的点火核开始，随后形成靠近催化剂壁的轴向细长火焰。催化化学和气相化学的耦合抑制了均匀点火，因为在点火核附近，到下面的催化壁的OH，H和O自由基通量是净吸收的，而且催化反应还耗尽了氢气。火焰拓扑包括交替剧烈燃烧和熄灭的细长流向条纹$\mathrm{[R}{Ë}_{\tau }=182$ 或岛屿 $\mathrm{[R}{Ë}_{\tau }=385$。熄灭的气相反应区$\mathrm{[R}{Ë}_{\tau }=385$其特征在于潜在的强烈催化反应速率。孤立的燃烧和熄灭的气态区的火焰拓扑和时空相关性表明，在实际的催化反应器中可以获得明显的表面温度不均匀性。