Secondary atomization of firefighting liquid droplets by their collisions
| Parent link: | Atomization and Sprays Vol. 29, iss. 5.— 2019.— [P. 429-454] |
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| Summary: | Title screen The results of experimental research into the interaction between droplets of various firefighting compositions colliding with each other in a gas are described. We establish the characteristics and occurrence conditions of four droplet interaction regimes: coalescence (fusion), bounce (interaction through a gas cushion between droplets without direct contact), separation (size and number of liquid fragments remain the same), and disruption (breakup of both droplets). In the experiments, droplet velocities, radii, and impact angles, as well as component composition, temperature, and surfactant proportions are varied in the wide range typical of fire containment and suppression. We determine the variation ranges of key parameters in the dimensional and dimensionless coordinate systems that provide active droplet disruption, i.e. secondary atomization. Such an atomization scheme can be arranged in any part of a combustion chamber, outside or directly within the fire zone. We use the so-called interaction regime maps based on the coordinate systems considering the dimensionless angular and linear impact parameters, as well as Weber, Reynolds, Ohnesorge, and capillary numbers. Droplet disruption enhances the endothermic phase transformations in the flame combustion zone, optimizes the use of liquid compositions, and reduces the containment time. Hence, the most valuable experimental results are the conditions determined for a several-fold increase in the number of small fragments of high-potential firefighting compositions due to colliding droplets. We show typical size distributions of the newly formed liquid fragments as compared to the initial ones. Режим доступа: по договору с организацией-держателем ресурса |
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2019
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| Online Access: | http://dx.doi.org/10.1615/AtomizSpr.2019030766 |
| Format: | Electronic Book Chapter |
| KOHA link: | https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=662919 |