- Author
-
Skamser, D. J.
|
Bentz, D. P.
|
Coverdale, R. T.
|
Spotz, M. S.
|
Martys, N. S.
|
Jennings, H.
|
Johnson, D. L.
- Title
- Calculation of the Thermal Conductivity and Gas Permeability in a Uniaxial Bundle of Fibers.
- Coporate
- Northwestern Univ., Evanston, IL
National Institute of Standards and Technology, Gaithersburg, MD
Master Builders Technology, Cleveland, OH
Illinois Superconductor Corp., Evanston, IL
- Journal
-
Journal of the American Ceramic Society,
Vol. 77,
No. 10,
2669-2680,
October 1994
- Keywords
-
fibers
|
thermal conductivity
|
permeability
|
transport properties
|
algorithms
|
temperature distribution
- Abstract
- A model of the local microstructure of a bundle of fibers is simulated and used as the basis for calculations of transport properties. This, in turn, can be used in a macroscopic model of the chemical vapor infiltration process. An expanding/overlapping circle representation of the micro-structure simulates the deposition of matrix in a uniaxial bundle of fibers. An iterative heat conduction algorithm is used to calculate the transverse thermal conductivity based on the thermal conductivities of the solid and gas phases. The permeability of gas through the microstructure is calculated for flow both parallel and transverse to overlapping cylinders using a Stokes equation and assuming a Darcys law behavior. Both the simulations of the microstructure and associated calculations of the transport properties compare favorably with experimental data. Darcys law for the behavior of gas in a bundle of fibers is shown to be valid for gas pressures of 5-13 kPa.