Abstract
This paper aims at studying the influence mechanism of gas temperatures (300 K, 400 K, 500 K, and 600 K) on gas atomization by simulating the integral atomization process of the close-coupled nozzle in vacuum induction gas atomization (VIGA). The primary atomization is simulated by the volume of fluid (VOF) approach, and the second atomization is studied by the discrete phase model (DPM) combined with the instability breakage model. The results show that, at an increased gas temperature, the influences of gas–liquid contact angle and gas temperature in the recirculation zone on the primary atomization are virtually negligible. However, increasing the gas temperature will increase the gas–liquid relative velocity near the recirculation zone and decrease the melt film thickness, which are the main reasons for the reduced mass median diameter (MMD, d 50) of primary atomized droplets. During the secondary atomization, increasing the gas temperature from 300 K to 600 K results in an increase in the droplet dispersion angle, which is beneficial to the formation of spherical metal powder. In addition, increasing the gas temperature, the positive effect of gas–liquid relative velocity increase on droplets refinement overweighs the negative influence of the GMR decrease, resulting in the reduced MMD and diameter distribution interval. From the analysis of the atomization mechanism, the increase in atomization efficiency caused by increasing the temperature of the atomizing gas, including primary atomization and secondary atomization, is mainly due to the increase in the gas drag force difference between the inner and outer sides of the annular liquid film.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.