Numerical investigation on the mixing performance of H2/CH4 blends and air in a curved miniature combustor

Mixing performance of H2/CH4 blends and air in a curved miniature combustor was numerically studied. The results indicate the following. (1) The mixing performance of H2 is much better than that of CH4 due to the preferential diffusion effect. (2) Mixing of CH4 and air is dominated by diffusion at low velocities, and convection at medium and high velocities. Mixing of H2 and air is dominated by diffusion at low and medium velocities, and convection at high velocities. (3) Increasing the nominal equivalence ratio leads to an increased diffusion rate due to the generation of large fuel concentration gradient perpendicular to the mainstream. (4) A higher hydrogen blending ratio intensifies fuel stratification at the combustor entrance, decreases the Dean vortices intensities, and deteriorates the mixing performance. (5) Among the factors investigated, average velocity and hydrogen blending ratio have the most and least significant effects, respectively, on the mixing performance.