層流境界層に形成される拡散火炎の構造と特性の数値解析

抄録

Numerical analysis of a diffusion flame established in a laminar boundary layer over a flat surface with fuel injection has been carried out for typical three cases. The conservation equations of continuity, momentum, energy and chemical species are solved using a finite-difference method for two-dimensional flow field with single step raction of methane with air. The flame shape, flow field, diffusion of component gas, heat transfer, and the structure of leading flame edge are examined in detail. A separation region is found to be formed in front of the leading flame edge, which brings a slow gas steam region near the flame edge. Caused by the concentration of oxygen diffusion in the slow gas stream region, a sharp peak of the reaction rate appears at the leading flame edge. Such an aerodynamic structure is inferred to take an important role in the flame stabilization. The reaction rate at the center of the flame zone is found to depend strongly on the free stream velocity, however, to be almost independent of the fuel injection velocity.