Experimental Study of a Near-wall Liquid Film Outflow with a Co-current Gas Flow from a Nozzle into a Vacuum. 1. Interaction Inside the Nozzle

• Published in: Fluid dynamics 2022-12, Vol.57 (Suppl 1), p.S13-S25
• Main Authors: Vyazov, Y. N., Prikhodko, V. G., Yarygin, I. V., Yarygin, V. N.
• Format: Article
• Language: English
• Subjects: Air flow; Classical and Continuum Physics; Classical Mechanics; Droplets; Ejection; Engineering Fluid Dynamics; Ethanol; Flow velocity; Fluid- and Aerodynamics; Gas flow; Nozzles; Physics; Physics and Astronomy; Vacuum chambers; Vapor pressure
• ISSN: 0015-4628; 1573-8507
• DOI: 10.1134/S0015462822601437

— Interaction of co-current gas flow with near-wall liquid film inside a nozzle (cylindrical channel) under ejection into vacuum is studied experimentally. Local parameters of near-wall films of ethanol, water and their mixtures under interaction with co-current air flow are measured with the help of capacity-type probes. It is shown that under conditions of experiments carried out a co-current flow exert strong dynamic impact on a near-wall liquid film, leading to intensive wave formation, detachment of droplet and their dispersion by co-current flow. It is found that the amount of liquid entrained from interphase boundary can reach over 50% from the initial flow rate of liquid. Flow structure of gas-droplet jet arising under ejection into vacuum is visualized with the help of laser illumination. Appearance of droplets backflows (at angles over 90° with respect to nozzle axis) is shown. Temperature of the film formed on the nozzle external surface is measured. It is shown that the film of liquid is cooled down to the temperature at which its saturated vapor pressure becomes equal to pressure in vacuum chamber.