| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 84 === A theoretical study of the MCVD process in the vertical tube
for the manufacture of optical fiber performs is presented. The
related flow and heat transfer, are obtained including the
effects of variable properties, tube rotation,buoyance, thermal
radiation, and laser effect. We adopt thethree-dimensional
optically thin limit approximation to model the radiation
mechanism of the aerosol particles. Our result indicate that
thermal rediation lower the deposition efficiency. When the folw
field is heated by laser, a significant increase in deposition
efficiency can beachieved as well as elevation of laser power.
Thus, there is a optimal laser beam width to have a highest
deposition efficiency. While the energydistribution of laser
beam moving toward center, higher depoisition efficiency is got
if the center of laser is located at the neighborhood near the
wall. A rotation speed of 60rpm, 120rpm, 300rpm, affects
deposition efficiencys lightly. But the deposition efficiency
will decreased when the tube is fixed because the local heating.
The increasein the inlet mean velocity enhances the effect of
the axial forced convection,thus results in the lower the
reaction percentage and higherdeposition efficiency since SiO2
particles are only formed over a portionof the cross-section
near the tube wall.
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