NOx Formation and Reducton in the Laminar Diffusion Flame

Recently the air is highly preheated by recycling the enthalpy of the fluegas in the combined power generation system. We focused our attention on NOx formation in the highly preheated air combustion. The combustion phenomena in the highly preheated air are still unclear. In the present study, the laminar, two dimensional, counterflow diffusion flame is established in the forward stagnation region of a porous cylinder by ejecting a fuel gas uniformly from the cylinder surface into a uniform laminar highly preheating air stream provided by the regenerator up to 1700 K. The extinction occurs at the higher strain rate, the higher the preheating air temperature becomes. The temperature dependency upon the strain rate is nearly exponential. The extinction flame temperature slightly increases with the strain rate. NOx formation in the diffusion flame is relatively high at the reference condition and the NOx in the diffusion flame increases with the increase of the preheating air temperature, but decreases with the strain rate.