Experimental study of single fuel jet combustion and high-cycle regenerative systems

Abstract: High Temperature Air Combustion (HTAC) is a technique toreduce consumption of fuel and decrease NOxformation in furnaces. The main change that occursin the furnace chamber is that the flow pattern of flue gasesaltered resulting in a more uniform heat transfer andtemperature profile. The usefulness of regenerative combustionis very clear, but the advantages have so far been accompaniedby high levels of pollutants, such as NOx. The combination of the regeneration technique andinternal flue gas recirculation has made HTAC a very attractivecombustion technology with application to heat treatment,reheating, and melting processes as well as for gasification ofbiomass.This work gives an introduction to regenerative combustionwith diluted air, including theory on flame stabilization.Furthermore, descriptions of new test furnaces are given withresults from a parametric study and from tests using schlierencolor visualization, direct photography, and laser Doppleranemometry. In the parametric study NOx-emission, CO-emission, lift-off, fluctuations, andsome flame characteristics are related to nozzle diameter,oxygen concentration, and preheat temperature. For theschlieren technique and direct photography, both still andhigh-speed cameras were used.