Basic research on radiant burners. Annual report, February 1987-January 1988

The first year's study demonstrated very close agreement between the radiant burner model predictions and experimentally measured flame liftoff. The second year's study, the subject of the report, focused on flashback of radiant burners. Flashback conditions were identified on a ceramic foam, ceramic-fiber and metal fiber burner with oxygen-enriched combustion air. The results showed that flashback occurred differently for the three burner types with the ceramic fiber burner the least prone to flashback and the ceramic-foam burner the most prone to flashback. Important flashback parameters were identified including the burner material conductivity, porosity, emissivity, and reactivity. The experimentally measured surface temperature and radiation were compared to radiant model predictions to identify when the actual burner performance deviated from the ideal behavior predicted by the model. The third year of the project will focus on measuring and modeling the total radiant output of radiant burner systems including the effects of hot-gas radiation and reverberatory screen radiation.