The Effect of High-Frequency Sound Waves on an Air-Propane Flame

This paper describes measurements of normal flame velocity of propane-air mixtures by the “burner method.” The experimental burner was so arranged that high-frequency sound could be introduced into the burner and allowed to travel through the gas-mixture column and combustion zone. Experimental measurements indicate that high-frequency sound does not change the magnitude of the normal flame velocity. Visual observations disclose a change of combustion-zone configuration of sound-influenced flames from the usual “cone” to a flattened bowl shape for laminar flames, and to a suspended violently agitated zone in the case of turbulent flames, both possessing remarkable stability.