B115 Characteristics of Rich-Lean Combustion Controlled Boundary Region of Rich-Lean Flames : 2^<nd> Report: Effects of Air Ratio and Velocity of Mixture Passing through Boundary Region on Limits of Flame Stabilization

Abstract

Effects of the velocity and the air ratio of the mixture supplied into the boundary region between the rich and lean flames on the characteristics of flame stabilization of the rich-lean combustion were investigated in order to develop a new type of a domestic boiling water heater and a warm heater with low emission of NOx and high TDR. The characteristics of stabilization of the rich-lean flames are substantially improved when the stoichiometric, the lean mixture and the air are supplied at the low velocity into the boundary region between the rich and lean flames, but not improved when the rich mixture is supplied into the boundary region between the rich and lean flames. The optimum velocity of the lean mixture supplied into the boundary region between the rich and lean flames exists for improving substantially the stability limits of the rich-lean flames. It is possible to develop the new type of burners with high performance of further low emission of NOx and high TDR by controlling the velocity and the air ratio of the mixture supplied into the boundary region between the rich and lean flames.