Flame stabilization in a planar microcombustor partially filled with anisotropic porous medium

Heat recirculation through the combustor walls is responsible in sustaining flames in microcombustors. Incorporating porous medium into microcombustors helps further enhance heat recirculation via the solid matrix. However, the problem of anisotropy arises when the pore size is comparable to the characteristic length of microcombustors. To quantitatively address the problem, an experimental study on the flame stability limits of premixed H2/air in a planar microcombustor partially filled with porous medium is undertaken. Three folding schemes, namely, parallel sheets, streamwise flow passage, and streamwise flow blocking, are employed to realize the anisotropic properties. By varying the width (W) and position (Lout) of the porous medium, the effects of folding schemes on the critical flashback (Ф2), and breaking‐through (Ф3) conditions are examined. The experimental results indicate that the disturbance to flow velocity in the transverse direction mainly influences Ф2, while Ф3 is greatly affected by the blocking normal to the flow direction. © 2017 American Institute of Chemical Engineers AIChE J, 63: 153–160, 2018