A numerical analysis of reactive flow in a liftoff flame is accomplished to
elucidate the characteristics of flame propagation velocity and volume integral of
reaction rate with the variation of fuel injection velocity at the fuel rich region, fuel
lean region and diffusion flame region. The increase of fuel injection velocity enhances
flame propagation velocity, but its effect on the flame propagation velocity is not much
greater under 4%. The increase of fuel injection velocity affects directly and linearly on
the flame surface area in the fuel rich region and so enhances volume integral of
reaction rate to accommodate the increment of fuel.