On a porous medium combustor for hydrogen flame stabilization and operation

In this study, the characteristics of hydrogen flame stabilization in porous medium combustor were investigated. The flame was observed in a quartz tube. The porous medium was oxide-bonded silicon carbide (OB-SiC) or aluminum oxide (Al2O3) with 60 PPI and 30 PPI pore size distributions. The results indicated that under a low equivalence operation, the flame would transform from surface combustion to interior combustion with an increased heating value. Under a high equivalence ratio, both interior combustion and flashback transition existed at the same time. The thermal conductivity of silicon carbide is higher than that of aluminum oxide. Thus, interior combustion region was more extensive under a low equivalence ratio operation with a high premixed gas velocity. Flashback was apparent for Al2O3 under high an equivalence ratio with low a premixed gas velocity. Consequently, hydrogen flame stability could be controlled by the pore size distribution and thermal conductivity of the porous media, input heating value and input equivalence ratio.