Diffusion of gases in porous solids: simulations and measurements. Seventh quarterly report, January 16-April 15, 1984

Technical Report · Sun Apr 01 04:00:00 EST 1984

OSTI ID:6857204

Evans, J W

The diffusion of a gas in a porous solid is analogous to two other classical problems: the conduction of heat in a two phase medium, one phase being insulating, and the conduction of electricity in a two phase medium one phase of which does not conduct. An example of the latter would be the problem of predicting the resistance of an electrolyte containing gas bubbles given the resistiviy of the electrolyte alone and information on the gas bubbles. This problem has been examined theoretically by both Maxwell and Bruggeman who provided equations that predict the variation of the effective resistivity (or its inverse, the effective conductivity) versus the volume fraction of bubbles. This analogy appears to have been left unrecognized and unexploited by investigators concerned with predicting diffusion rates in porous soldis. It enables the prediction to be made using the Maxwell or Bruggeman equations. Conversely the Monte Carlo simulations of gaseous diffusion in porous solids being carried out at Berkeley should yield predictions of the effective conductivity of electrolytes containing gas bubbles. Some results from the new algorithm for predicting gaseous diffusion rates discussed in the last quarterly report are compared to the predictions of the Bruggeman and Maxwell equations. Clearly the predictions of the Monte Carlo simulations agree with the classical equations. It has become apparent that the Monte Carlo simulations will provide spin offs in other important areas of transport phenomena, besides those of diffusion in porous solids.

• Research Organization: California Univ., Berkeley (USA). Dept. of Materials Science and Mineral Engineering
• DOE Contract Number: FG22-82PC50796
• OSTI ID: 6857204
• Report Number(s): DOE/PC/50796-T5; ON: DE84010822
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
DIFFUSION
FLUIDS
GASEOUS DIFFUSION
GASES
MATERIALS
MONTE CARLO METHOD
POROUS MATERIALS
SIMULATION