Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.
This report presents a special form of combustion, called flameless combustion. In contrast to the combustion within stabilized flames, temperature peaks can be avoided at flameless combustion. Critical points of this technology are the realization of thermofluodynamic conditions which stabilize the flameless combustion process and a design to reach flameless conditions. Burners for flameless combustion usually show complex geometries which make simplified schemes difficult and inappropriate. In this case, the present paper proposes a study to determine the viability of a flameless burner design for experimental investigation and a combustion chamber on a laboratorial scale able to use high temperature air to reduce pollutant emissions. During the experiments, it will be used natural gas and preheat air. The influence of the field flow, chamber temperature and preheating air temperature on reaction zone volume was examined using techniques capable of analyzing the temperature field in the combustor. The main conclusions were: a) in contrast to the flames, the combustion had low internal temperature gradients; b) the system has promoted changes in the volume characteristics of combustion significantly reducing pollutants: NOx, CO and UHC (Unburned Hydrocarbons); c) to same conditions no visible flame was observed during the test.