T he evaporation,ignition and combustion characteristics of n-hexane and iso-octane fuel droplets are experimentally investigated under acoustic excitation at 100,200,500 Hz,and sound pressure of 12.5,25.0 and 37.5 Pa to determine the effects of acoustic waves at different frequen-cies and pressures on the ignition and combustion of n-hexane and isooctane fuel droplets.The re-sults show that the acoustic oscillation does not change the control mechanism of droplet combus-tion,which is still controlled by the droplet evaporation process.After applying a sound field exci-tation of 100 Hz and 25 Pa,the ignition delay time of n-hexane and iso-octane droplets are reduced by 72％and 40％,respectively.The response of fuel droplet combustion flame to acoustic wave oscillation is characterized by low-pass filtering.When the frequency of sound wave is 100 Hz,the flame pulsation of n-hexane and iso-octane droplet combustion occurs obviously.In the oscillating environment,the lower the sound wave frequency and the higher the pressure,the higher the combustion rate of n-hexane and iso-octane fuel droplets.Both of them show the maximum com-bustion rate at 100 Hz and 37.5 Pa,which are 0.384 2 and 0.313 9 mm2·s-1,respectively,in-creasing by 43.2％and 52.6％compared with the case without oscillation.
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