Effect of the Vapor Flow on the Drop Spreading in the Leidenfrost Regime

Abstract : Spray cooling is an attractive technique for its ability to dissipate high thermal fluxes with satisfactory spatial homogeneity and low coolant fluid consumption. This work presents an experimental investigation of the deformation process of liquid droplets impinging onto a hot substrate in the film boiling regime. The particular case of the bouncing regime is the main target of the paper. Droplets impact onto a smooth substrate (averaged roughness about 0.1?m) heated above 600°C, and they are observed by shadowgraphy using a high-speed camera. After image processing, the deformation of droplets in the 100 µm size range is characterized with a temporal resolution of about 0.2 µs and a spatial resolution in the order of 1-2 microns. Experiments are performed at moderate impact velocities (2-8 m/s). Under these conditions, bouncing of the droplets is observed without any fragmentation. Measurements include liquids of different viscosities (water, ethanol, 5 mixtures of water and glycerol), which allows covering a relatively wide range of Ohnesorge numbers (0.01
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Communication dans un congrès
IHTC-15 : 15th International Heat Transfer Conference, Aug 2014, Tokyo, Japan. 978-1-56700-421-2, 2015, International Heat Transfer Conference 15 : 2014, 10-15 August, Kyoto, Japan. 〈10.1615/IHTC15.min.009574〉
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https://hal.univ-lorraine.fr/hal-01444401
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Soumis le : mardi 24 janvier 2017 - 09:34:43
Dernière modification le : jeudi 22 mars 2018 - 14:40:02

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Guillaume Castanet, Ophélie Caballina, Alexandre Labergue, Michel Gradeck, Fabrice Lemoine. Effect of the Vapor Flow on the Drop Spreading in the Leidenfrost Regime. IHTC-15 : 15th International Heat Transfer Conference, Aug 2014, Tokyo, Japan. 978-1-56700-421-2, 2015, International Heat Transfer Conference 15 : 2014, 10-15 August, Kyoto, Japan. 〈10.1615/IHTC15.min.009574〉. 〈hal-01444401〉

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