Abstract
A numerical analysis on the combustion characteristics with preheated low-oxygen air was made for counterflow diffusion flame by using the detailed chemistry. The effects of preheating air and lowering oxygen concentration on the combustion characteristics and NO emission index were examined under the same maximum flame temperature. As the oxygen concentration decreases, the concentrations of HCN, N and NO increase, and the NO mass production rate increases and the fuel mass consumption rate decreases, thus NO emission index increases.
