par Legros, Jean Claude 
;Lutoshkina, Olga;Piskunov, Maxim M.V.;Voytkov, Ivan
Référence Experimental thermal and fluid science, 96, page (154-161)
Publication Publié, 2018-09
;Lutoshkina, Olga;Piskunov, Maxim M.V.;Voytkov, IvanRéférence Experimental thermal and fluid science, 96, page (154-161)
Publication Publié, 2018-09
Article révisé par les pairs
| Résumé : | We have established conditions for stable triggering of the explosive breakup for heterogeneous water drops induced by immersion in high-temperature gas (air) at more than 800 K. The water drop heating is enhanced by small graphite solid particles of 2 × 2 × 1 mm, 2 × 2 × 2 mm and 2 × 2 × 3 mm inserted into drops. The properties of the graphite such as porous and layered structure, moisture content, and surface roughness play determining roles. Experiments show that heterogeneous water drops can boil during a short time and produce clouds of tiny droplets. Heating times of heterogeneous drops until the breakup do not exceed a few seconds and usually last for less than three. We have identified the main stages and the mechanism of heterogeneous drop heating, as well as vaporization at the internal interface and at the free surface of a drop. A high-speed video camera and the TEMA Automotive Software with a number of tracking algorithms are used for measurements. The analysis of experimental results shows that during the fragmentation of large heterogeneous drops at high temperatures, more than 100 small droplets are formed. The obtained data are a basis for novel technologies of effective fire extinguishing that involve the multiple growth of water evaporation area in a flame. |
