Study of supercooled water droplet chain evolving in a cold environment: Experimental and modelling study
Mehdi Stiti  1@  , Alexandre Labergue  1@  , Guillaume Castanet  1@  , Fabrice Lemoine  1@  
1 : Laboratoire dÉnergétique et de Mécanique Théorique Appliquée
Université de Lorraine, Centre National de la Recherche Scientifique : UMR7563
Université de Lorraine - ENSEM - ESSTIN, 2 avenue de la Forêt de Haye, TSA 60604, 54518 Vandoeuvre-les-Nancy Cedex -  France

Knowledge of the temperature of supercooled water droplet is essential for aircraft certification. In the present paper, characterisation of supercooled droplets is made by Laser Induced Fluorescence (LIF). LIF technique allows a discrimination of the state of the droplet and a measurement of the droplet's temperature.The technique is here used to characterise droplets falling in a cold environment. An experimental setup designed for supercooled droplet generation is built allowing a control of the ambient temperature for minimum temperature of -55°C. The study is performed on a line of equally-spaced droplets. This configuration allows changing several parameters as the droplet diameter $D_{inj}$ the inter-droplet distance and the droplet injection temperature $T_{inj}$. Heat transfers in a droplet line are well known in the literature and their effect on Sherwood and Nusselt are still an opened issue. In this study, Nusselt and Sherwood numbers are estimated from experimental results and compared with correlation of isolated droplets. The comparison allows a quantification of the droplet interaction effect on heat and mass transfers. It is then shown that the inter-droplet distance parameter has a strong influence on the evolution of the correction of both Nusselt and Sherwood numbers.

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