Effect of nozzle upscaling on coaxial, gas-assisted atomization

Mass flow scaling of gas-assisted coaxial atomizers from laboratory to industrial scale is major interest for a wide field applications. However, there only scarce knowledge and research concerning the effect atomizer scale-up on liquid breakup spray characteristics. The main objective this study therefore derive basic principles jet using upscaled nozzles increase mass rate [Formula: see text]. For that purpose, with same geometrical setup but increased sizes have been designed experimentally investigated text], 50, 100, 500 kg/h, while aerodynamic Weber number We aero gas-to-liquid ratio GLR kept constant. primary was recorded via high-speed imaging, core length L C frequency Kelvin–Helmholtz instability f K were extracted. Applying these results as reference data, highly resolved numerical simulations performed gain deeper understanding scaling. In case keeping constant, it has shown by both experiments morphology, given pulsating disintegration fiber-type fragments, remains almost unchanged degree upscaling n. normalized text] found be considerably increasing reason decreased gas velocity v at nozzle exit n, which leads momentum flux j an attenuated exchange between phases. Accordingly, calculated turbulence kinetic energy specific in phase decrease This corresponds KHI n or respectively, confirmed simulations. behavior two liquids different viscosities . obtained allow first-order estimate characteristics, where influence can incorporated into Re liq terms