Surface flame patterns and stability characteristics in a perforated cordierite burner for fuel reformers

Abstract

The combustion characteristics of surface flames in a perforated ceramic burner, which can be used as the main burner of a fuel reformer in fuel cell systems are experimentally investigated. The effects of the equivalence ratio and heating rate were studied to find less emission and a more stable surface flame. A specially designed fuel/air mixer was fabricated to produce a stable surface flame. The results show that surface flames can be classified into green, red radiant, and blue surface flames as the equivalence ratio decreases. Each flame is maintained very stable at the specified equivalence ratio and has the same flame characteristics at any orientation of the ceramic burner. In particular, the blue surface flame is found to be very stable at a very lean equivalence ratio at 8 to 23.2 kW heating rates. The exhausted NO x measurement shows that the blue surface flame represents the lowest NO x emission since it remains very stable at a lean mixture ratio. CO emission is also much lower compared with the bunsen flame due to lean combustion.