THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

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Experimentally determining the effects of water droplets collision when mixing aerosol with gas flow at different heating temperatures

ABSTRACT
The article presents the results of experimental studies of the collisions characteristics for water droplets in an aerosol at its entry into the air counter flow. The temperature of the latter ranged from 20 °C to 500 °C. Experiments were also carried out with the flow of combustion products having a temperature of 800-850 °C. The initial dimensions (radii) of the droplets in the aerosol were 50-1000 μm. Visualization of the droplet motion in the counter flow of air and combustion products required the use of a hollow cylinder made of quartz glass with a height of 1 m and an internal diameter of 0.15 m, a cross-correlation complex and optical methods (Particle Image Velocimetry, Particle Tracking Velocimetry, Interferometric Particle Imaging). The characteristics of the droplet interaction (size, velocity, total surface area of the liquid before and after) were controlled using a high-speed video camera and tracking algorithms in the Tema Automotive software package. The main modes of drops interaction have been identified: bounce, coagulation, scatter, and breakup. The statistical information database has been obtained to describe the interaction modes using diagrams, taking into account the ratio of the sizes of colliding drops, velocities of their motion, and an angle between trajectories of motion. The influence of gas temperature on the probabilistic criteria of droplet collisions, as well as the integral criterion characterizing the change in the liquid surface area due to the intensification of droplet collisions in the gas medium has been established.
KEYWORDS
PAPER SUBMITTED: 2018-09-17
PAPER REVISED: 2019-02-20
PAPER ACCEPTED: 2019-03-06
PUBLISHED ONLINE: 2019-04-07
DOI REFERENCE: https://doi.org/10.2298/TSCI180917103V
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