This study analyses the hydrogen permeation flux model with (1) modifications in

the defect concentration calculations where the concentration of substitutional

cation on cerium site was utilised as the independent variable for the calculation,

instead of the previous step-wise calculation with the concentration of oxygen

vacancy as the independent variable and (2) the additional terms to include the

oxygen partial pressure gradients for calculation of hydrogen permeation flux. The

modification in the defect concentration method allows a short model simulation

run time, which consequently allows incorporation of the concentration constraints

in the parametric sensitivity analysis, but still produces the same set of defect

concentrations as calculated in the previous methods. It was also found here that

the discrepancy between the model and experimental results (in terms of the effect

of changes in hydrogen partial pressure gradients on the hydrogen permeation flux) was not due to the influence of oxygen partial pressure gradients. Parametric

sensitivity analysis showed that there was no significant difference in the

sensitivity of the model by comparing Case A and B. The result of parameter

tuning to predict the hydrogen permeation flux for 5% thulium doped strontium

cerate in Case B showed a similar trend to the previous study (Case A). These

results suggested negligible oxygen ion conductivities in these types of membrane,

as reported in the literature.

Numerical Study of Hydrogen Permeation Flux in Ytterbium Doped Strontium

Cerate and Thulium Doped Strontium Cerate (II). M.Matsuka, R.D.Braddock,

I.E.Agranovski: Mathematics and Computers in Simulation, 2009, 79[9], 2713-23