| Summary: | 碩士 === 國立臺灣大學 === 機械工程學系 === 86 === The present study investigates analytically the effect of surface
tension (Thomson-Gibbs effect) on the growth rate of a single spherical
crystal in a subcooled liquid. The heat conduction equations along with
appropriate boundary and interface conditions are solved by using the
small-time series expansions method. A nonlinear Shanks
transformation is adopted to improve the convergence property of the
series so that it can be applied to large time. Results show that in
general,
the surface tension effect is to reduce the growth rate of the crystal.
However, for a given subcooling condition, there exists a critical value
of the surface tension above which the growth rate of the crystal increases
temporally within certain range of time. Variations of this critical value of
surface tension with degree of subcooling (Stefan number) have been
determined. Also, analytic expressions for the relations between the
crystal growth and surface tension have been found under small
subcooling conditions (small Stefan number).
|
|---|
