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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

USING PLANAR LASER-INDUCED FLUORESCENCE TO STUDY THE PHASE TRANSFORMATIONS OF TWO-COMPONENT LIQUID AND SUSPENSION DROPLETS

Get access (open in a dialog) DOI: 10.1615/IHTC16.bae.022803
pages 747-754

Sinopsis

High-temperature gas-steam-droplet systems are now of the strong interest in the field of fundamental thermophysical investigations. They contribute to creating and developing technologies of the thermal treatment of liquids, the hydrogen and syngas production by heating the water-oil emulsions and the suspensions, etc. System parameters are usually selected depending on results of numerous experiments. Thus, the lack of the basic knowledge is observed concerning conditions and characteristics for the high-temperature (over 500°C) heating and evaporation of water and water-based liquids. Using the Planar Laser-Induced Fluorescence (PLIF), we performed experiments to determine evaporation dynamics of homogeneous and heterogeneous droplets of liquids, conditions of their boiling and explosive breakup. For the 1−2 mm water droplets, the distribution of highly non-homogeneous and non-steady temperature field was detected by high-speed cross-correlation video recording and the Tema Automotive software. We identified highly nonlinear dependences of evaporation rate on heating temperature and time as well as water droplet size. For the two-component liquids and water-based suspensions of graphite, we revealed unsteady temperature fields and established mechanisms and regimes of the explosive breakup of the heterogeneous droplets when heated. The regimes differ in the number and dimensions of the emerging gas-liquid fragments as well as the durations of the main stages. The temperature variations at the water/solid or water/flammable component interfaces were determined corresponding to each boiling and breakup regime. Using the PLIF, we studied reasons and mechanism of the explosive breakup of water droplets with single large carbonaceous inclusions when heated.