Date of Award

Fall 2003

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Computational Analysis and Modeling

First Advisor

Raja Nassar

Abstract

This dissertation consists of two parts. Part one deals with three-dimensional laser induced chemical vapor deposition (3D-LCVD), whereas part two deals with a Pennes model of a 3D skin structure. LCVD is an important technique in manufacturing complex micro-structures with high aspect ratio. In part one, a numerical model was developed for simulating kinetically-limited growth of an axisymmetric cylindrical rod by pre-specifying the surface temperature distribution required for growing the rod and then by obtaining optimized laser power that gives rise to the pre-specified temperature distribution. The temperature distribution at the surface of the rod was assumed to be at the unsteady state, and a least squares method was implemented to obtain the optimized laser power by minimizing the deviation between the calculated temperature distribution and the pre-specified temperature distribution. Results from this model were compared with results from Chen's[29] model, which assumed that the temperature distribution at the surface of the rod was at steady state. Also, two different mesh sizes were used in these models to measure the effects of mesh size on the final results.

Investigations on instantaneous skin burn are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. The Pennes' bioheat model is a widely used model for predicting the degree of skin burn. In part two, a domain decomposition method was developed for solving a 3D Pennes' bioheat transfer equation in a triple-layered skin structure. The Pennes' bioheat transfer equation was discretized by the Crank-Nicholson scheme. A least squares method was incorporated in the model so that one could calculate the required laser power for the skin structure to reach a pre-specified temperature at a pre-specified location after a pre-specified laser exposure time. Numerical results of this model were obtained and discussed.

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