Study Of Atomization Model Of Prefilming Atomizer Considering Mass And Heat Transfer Processes

Abstract

Liquid film propagation and breakup in the prefilming atomizer is controlled by two instabilities, one is the Kelvin- Helmholtz (KH) instability leading to the formation of longitudinal waves, and the other is the Rayleigh-Taylor (RT) instability causing the liquid film to break into droplets. At present, most of the atomization models of prefilming atomizers are established without considering the effect of the heat and mass transfer processes between the high-temperature gas and liquid film. The current study for the first time explores this effect on the change of KH and RT instabilities and film propagation and breakup processes, and implements this effect into the atomization model. Results show that the mass and heat transfer processes promote the development of KH instability and have an inhibitory effect on the development of RT instability. Furthermore, the most amplified wavelength of transverse waves caused by RT instability is used to characterize the Sauter mean diameter (SMD) and droplet size distribution of the droplets. The droplet SMD of the primary breakup decreases linearly with the increase of temperature, but the uniformity of the droplets deteriorates. This newly developed atomization model can be used to predict the size and distribution of droplets more accurately.