| Summary: | 碩士 === 淡江大學 === 化學工程學系 === 84 === The mathematical model describing the evaporation of solution
droplet in spray pyrolysis was developed and verified. The
established model not only simultaneously considered the
transfer of mass, momentum, and energy inside and around the
droplet, but also considered the effects of heat of
precipitation on the evaporating solution droplet. The concept
of real solution was also introduced during calculation to
estimate the saturated vapor pressure above the surface of
solution droplet. The study indicated thinside the solution
aerosols, the diffusion and convection mass transfer are
comparable. The simulated results show that: (a) raising the gas
temperature increased the solvent evaporating rate and surface
solute concentration rising rate, resulting in the formation of
bigger solid crust; (b) lowering the concentration of starting
solution increased the evaporating rate and the time required
for the droplet surface to reach saturated concentration,
resulting in the formation of smaller hollow solid; (c)
increasing the contents of solvent vapor in gas phase decreased
the solvent evaporation rate and slowed down the increase of
surface solute concentration, but increased the droplet
temperature.
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