Pore Size Distribution Effect on the Mass Transfer and Reaction in a Cylindrical Porous Gas Sensitive Medium

Based on the pore size distribution simulation and the derivation of the effective diffusion coefficient, a mathematical model describing the mass transfer and chemical reaction in a cylindrical gas sensitive porous medium is formulated. The reaction features and the effective utilization of the gas sensitive porous medium are analyzed under different pore size distribution. The results indicate that, an increase in porosity or in the most probably pore diameter leads to a higher mass transfer rate of the target gas, while the surface chemical reaction ability decreases. Depending on the calculated value of the Thiele number, the variation of the gas sensitivity and the effective surface utilization can be analyzed. The gas sensitivity and the effective utilization coefficient of the gas sensitive porous medium can be controlled by adjusting pore structure parameters. This will be useful for the pore structure design of gas sensor and choosing the most reasonable operation conditions.