Interference between an acoustic field and premixed flame is investigated. Two kinds of transport processes are considered to cause combustion promotion in the acoustic field. One is diffusive transport. It has long been considered that the acoustic oscillation promotes diffusion, like turbulence does. The other is convective transport. Acoustically induced thermal convection that is driven by a kind of acoustic radiation force in a standing acoustic field has been previously found (Tanabe et al., Proc Combust Inst 28:1007-1013, 2000. The burning rate of an isolated single droplet is promoted by this thermal convection. In this report, the influence of the acoustic oscillation on the premixed flame propagation was examined through experiment and numerical simulation. The gravitational force was not taken into account since it complicates the combustion phenomena. The experiment and numerical simulation were done in microgravity condition. Each influence of turbulent diffusion and thermal convection were evaluated from the burning velocity, flame shape and flame speed, since the diffusive effect has been considered to have an influence on the burning velocity, while the convective effect has an influence on the flame speed and flame shape. As a result, it was clarified that the diffusive effect has a minor influence on the

The influence of an acoustic field on premixed flame propagation was examined by numerical simulation and experiment. The influence was evaluated from the two points of view. One is the diffusive transport and the other is convective transport. The particle oscillation by sound is considered to increase diffusivity in the acoustic field like turbulent diffusion. The thermal convection occurs when the density difference exists in the acoustic field. It is considered that flame front is deformed by this thermal convection. To analyze the diffusive and convective influence of the acoustic field, experiment and numerical simulation with strong standing wave had been made. To evaluate the influence of the thermal convection, buoyancy-induced natural convection was removed. As the result, the effect of the thermal convection is clearly observed in both experiment and numerical simulation when the sound pressure level is above 150dB. And the numerical simulation results agreed with experimental results. The burning velocity changes in the acoustic field. The effect is significant especially for a flame that propagates perpendicular to the particle oscillation.