Spray formation by a swirl spray jet in low speed cross-flow

Breakup and spray formation of swirl liquid jets introduced into a low-speed cross-flow are experimentally investigated. Effects of the cross-flows on the macro and microscopic spray parameters are optically measured in terms of jet Weber number and liquid-to-gas momentum ratio. At lower jet Weber numbers, the liquid stream undergoes Rayleigh jet breakup. At higher momentum ratios, bag breakup occurs and tends to distort the liquid column into a loop-like structure. As the jet Weber number rises, stronger aerodynamic interaction and secondary flows cause multi-mode breakup. Regardless of the momentum ratio, the spray profile is hardly altered at higher jet Weber numbers. The cross-flow promotes the jet breakup and renders a finer spray in an entire range of injection velocities.