Combustion and thermal performance of a novel preheated miniature combustor with a flame holder and various porous medium materials

Abstract

<p>A novel preheated combustor with plate porous medium PM and a flame holder is adopted in this study for the purpose of improving the lean premixed combustion LPC performance. For further optimizing the aforementioned combustor, the effects of the PM material on the LPC behavior of methane-air and the burner thermal performance are investigated and analyzed in detail. The porous media of Silicon Carbide SiC, Zirconia ZrO2, and Aluminium Oxide Al2O3 are applied in this work. Four combustion behaviors (flame extinction, combustion next to the PM (CNP), combustion within the PM (CWP), as well as flashback) occur successively with the reduced equivalence ratio, and the operating conditions in the case of CWP are recommended to be employed in the practical application. The results show that the flow recirculation zone grabs the lean premixed flame immerged into the PM significantly. The CWP operating range is the largest in the case of ZrO2 with the smallest thermal conductivity and that is the smallest in the case of Al2O3 with a moderate thermal conductivity. However, the thermal performance of the burner with the Al2O3 porous medium is the best. Therefore, if the CWP operating range in the case of Al2O3 is sufficient, the Al2O3 porous medium should be employed. This study helps us gain a further understanding of the lean premixed combustion and offers a new configuration to improve its performance.</p>