Hydrodynamic and Mass Transfer of a Contaminated Water Droplet


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Abstract


This paper presents the results of a parametric numerical study in which the mass transfer into a spherical water droplet was computed over the range 0.1< Re <100 for different values of the polar angle θcap characterizing the extent of a rigid cap at the rear of the water droplet, for a Schmidt number Sc=550 and a fixed viscosity ratio between the dispersed phase and the continuous phase κ=55. The results show that for low Reynolds numbers (Re<2) and relatively low Peclet numbers the contamination reduces the mass transfer flux. The average Sherwood number increases with a stagnant-cap angle increase and reaches a maximum value corresponding to the average Sherwood number for a clean water droplet (θcap=180°). However for larger Reynolds numbers and because of the structure of the streamlines and their incidence on isoconcentrations contours, the average Sherwood number maximum is reached at θcap=102°, θcap=70°, θcap=57° and θcap=50° for Re=2, Re=10, Re=50 and Re=100, respectively.
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Keywords


Water Droplet; Interface Contamination; Stagnant-Cap Model; Mass Transfer

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References


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