THESIS
2002
xiv, 101 leaves : ill. ; 30 cm
Abstract
The evaporation process of a multi-component droplet is complex because it involves transient interfacial heat transfer, multi-component phase change at the droplet inter-phase and diffusion process within the droplet. The difficulties associated with the study of the fluid dynamics and heat transfer of multi-component droplet evaporation are the extremely different volatilities and the rapid variation of the mass fraction within a droplet of the components. Because of the complexity of multi-component droplet evaporation process and the lack of experimental data on the transient evaporation rate, the mass fraction of the components and the droplet temperature, the mechanisms controlling the phenomena of multi-component micro-droplet evaporation are not well understood. Advanced optical...[
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The evaporation process of a multi-component droplet is complex because it involves transient interfacial heat transfer, multi-component phase change at the droplet inter-phase and diffusion process within the droplet. The difficulties associated with the study of the fluid dynamics and heat transfer of multi-component droplet evaporation are the extremely different volatilities and the rapid variation of the mass fraction within a droplet of the components. Because of the complexity of multi-component droplet evaporation process and the lack of experimental data on the transient evaporation rate, the mass fraction of the components and the droplet temperature, the mechanisms controlling the phenomena of multi-component micro-droplet evaporation are not well understood. Advanced optical diagnostic instruments were used in this study for simultaneously measuring the size, velocity and temperature (refractive index) of individual spherical multi-component droplet. The size and velocity of the droplets were measured using a high accuracy laser Phase-Doppler Anemometry (PDA) system. The refractive index of the droplet was determined by measuring the primary rainbow angle location with a high resolution Charged Coupled Device (CCD) camera. Pure water and different components of ethanol were used. A silicon oil bathed cylindrical transparent central-channel furnace was manufactured, which provides a hot air temperature inside of the channel from 30℃ to 200℃. The diameter and temperature of droplets were measured under different hot air temperature. Experimental results have shown that the evaporation characteristic of multi-component droplet varies with temperature condition and component.
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