Computational Modeling of Multicomponent Diffusion Using Fortran

Abstract

The objective of this thesis was to develop a Fortran software package, using three modules, in order to extract diffusion data from concentration profiles and to predict future concentration profiles. The first module will be a finite difference code that uses the multicomponent form of Fick's First Law, and the time evolution of concentration will be calculated using the implicit Crank-Nicholson method. The second module will take into account movements of boundaries between regions in the interdiffusion zone, via equations that assume local equilibrium, and take into account that mass must be conserved. The first and second module will be used to predict how measured concentration profiles will change with time. The purpose of the third module will be to extract diffusivity data from measured concentration profiles. This module will use a matrix inversion method to calculate the diffusivities. In conclusion, the original objective of this project was not met to its full completion. Several factors contributed to this shortcoming, but the primary obstacle was the correlation between the software and the input data. While the software ran successfully with many different known solutions, it did not perform well using actual concentration profile data from the U.S. Army Research Laboratory. Most likely, this is due to the limited amount of species data, the accuracy of the data itself, and the spacing between each data point. All efforts should be taken to obtain more accurate, smoother input data which will allow the software to run with fewer obstacles and, in turn, produce cleaner output data. Once the input data is appropriate, the programmer should return to fine tune the individual software programs to allow them to work with the new data. This may require using a filtering subroutine in order to accept only worthy data from the input stream.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jul 01, 2006
Accession Number
ADA454884

Entities

People

  • Mi Hael V. Pasquariello

Organizations

  • University of Connecticut

Tags

Communities of Interest

  • Advanced Electronics
  • Weapons Technologies

DTIC Thesaurus Topics

  • Algorithms
  • Boundaries
  • Computational Modeling
  • Computer Programs
  • Difference Equations
  • Differential Equations
  • Diffusion
  • Diffusion Coefficient
  • Diffusivity
  • Equations
  • Materials Science
  • Military Research
  • Procedures (Computers)
  • Thermal Conductivity
  • Thin Films
  • Three Dimensional
  • Two Dimensional

Readers

  • Database Systems and Applications
  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Materials Science and Engineering.

Technology Areas

  • Space
  • Space - Hall-Effect Thruster