MASS-TRANSFER WITH GRAPHITE OXIDATION IN GAS-MIXTURE LAMINAR-FLOW THROUGH CIRCULAR TUBE

Experiments and numerical analyses on mass transfer in a gas mixure laminar flow through a circular graphite tube accompanied with graghite oxidation were performed to clarify characteristics of graphite corrosion in connection with the primary cooling pipe rupture accident in a high temperature gas cooled reactor. In the experiment, inlet Reynolds numbers ranged from 16 to 320, graphite temperatures from 600 to 1,050-degrees-C and inlet oxygen mass fractions from 10 to 50%. IG-110 and PGX graphites were used. The mass transfer coefficients in the experiment at a high temperature were less than those obtained on the basis of analogy between heat and mass transfer. It was found from the numerical analysis that the reduction of mass transfer coefficient resulted from the injection flow from the wall. The mass fractions of carbon monoxide and carbon dioxide in the experiment were well predicted on the basis of the one-dimensional numerical analysis in which graphite oxidation and carbon monoxide combustion were taken into consideration.