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Collisions of Two-Phase Liquid Droplets in a Heated Gas Medium
Pavel Tkachenko1, Nikita Shlegel1, Pavel Strizhak1
1Scientific and Educational Department of I.N. Butakova, Power Engineering School, National Research Tomsk Polytechnic University, 634050 Tomsk, Russia.
Entropy (Basel, Switzerland)
|November 27, 2021
Summary
Investigating two-phase liquid droplet collisions in hot air reveals that vapor bubble content significantly influences collision outcomes like coalescence and breakup. Understanding these dynamics is crucial for industrial applications.
Area of Science:
- Fluid dynamics
- Thermodynamics
- Multiphase flow
Background:
- Industrial processes often involve liquid droplets in heated gas environments.
- Understanding droplet interactions is key to optimizing heat and mass transfer.
- The influence of internal vapor content on droplet collision dynamics remains an area needing detailed study.
Purpose of the Study:
- To experimentally investigate the collision behavior of two-phase liquid droplets in a heated gas medium.
- To determine how varying vapor content within droplets affects collision regimes and fragment characteristics.
- To identify conditions where vapor bubbles significantly impact droplet interactions.
Main Methods:
- Experiments conducted in a closed heat exchange chamber with air heated to 400-500 °C.
- Varying initial droplet size, velocity, impact angle, and vapor volume percentage (up to 90%).
- Recording droplet collision regimes (coalescence, bounce, breakup, disruption) and secondary fragment properties.
Main Results:
- Distinct differences in collision regimes and secondary fragment size distribution were observed based on vapor content.
- The percentage of vapor bubbles within droplets was found to significantly alter interaction outcomes.
- Conditions were identified where vapor bubbles had a substantial or minimal effect on collision dynamics.
Conclusions:
- The internal vapor fraction is a critical parameter governing two-phase droplet collision outcomes.
- Results provide insights into the complex interplay between vapor content, droplet dynamics, and heated gas environments.
- Findings are relevant for optimizing processes involving sprays and atomization in high-temperature industrial settings.
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