Analysis Study of Swirling Air Stream Effects on Spray Atomization

This paper investigates the effects of swirling air stream on a viscous hollow cone spray atomization with sinuous instabilities. The dimensionless dispersion equation of wave growth rate was derived with linear stability analysis. The dispersion equation is solved by numerical method and swirling air stream effect on maximum growth rate and its corresponding unstable wave number is investigated. The results show that the maximum growth rate of a swirling liquid sheet subjected to purely outer axial air is more pronounced compared to its counterpart subjected to purely inner axial air. In swirling air stream، swirling of outer air has more effect compared to inner air on maximum growth rate and improves the atomization. The combination of inner and outer air stream swirling has the highest effect on wave growth rate. The growth rate can be related to the breakup length of the liquid sheet and when the growth rate increases، breakup length is shorter. The drop diameter is dependent to the wave number and decreases with the increase of the wave number that can afford improvement of combustion and decrease the specific fuel consumption.