Fundamental Researsh on Structure around a Flame Base and Stability Mechanism of Catalitycally Stabilized Diffusion Flame

本文采用实验和数值方法研究了喷注燃料（甲烷-氮混合物）的催化或非催化扁平多孔板层流边界层中火焰基底周围的火焰结构和扩散火焰的稳定机理。当燃料浓度降低时，火焰变得不稳定，火焰基底振荡。当使用催化多孔板时，在火焰稳定极限处的燃料浓度比非催化情况低。实验结果还表明，在低燃料浓度条件下，多孔板温度越高，火焰越稳定，因为多孔板的热损失越小。这些结果表明，在靠近火焰底部的催化反应中，应保持多孔板温度较高，从而在较低燃料浓度条件下稳定火焰，减少热损失。火焰位置和温度分布的数值计算结果与实验结果吻合较好。然而，这种振荡现象是无法预测的。

A flame structure around the flame base and a stability mechanism of diffusion flame in a laminar boundary layr ober a catalytic or non-catalytic flat porous plate with fuel (methane-nitrogen mixture) injection have been inverstigated experimentallyn and numerically. When the fuel concentration is decreaed, the flame becomes unstable wiht flame base oscillation. As the cataytic porous plate is used, the fuel concentration at the flame stabilization limit becomes lower compared to non-catalytic case. The experimental results also revealed that the flame can be stabilizud with lower fuel concentration condition for higher porous plate temperature, because the heat loss to the porous plate is reduced. These results suggest that the catalytic reaction near the flame base is supposed to keep the porous plate temperature high, and then, the flame can be stabilizud with lower fuel concentration condition, reducing the heat loss. The numerical results of flame location and the temperature profile show good agreement with experimental ones. The oscillating phenomenon, however, can not be predicted.