A parametric study of the heat and mass diffusion dimensionless parameter in SOFC with DIR by lattice Boltzmann method

In the present study, the lattice Boltzmann method (LBM) is employed to study the diffusion phenomenon in solid oxide fuel cell (SOFC) with direct internal reforming (DIR). The main focus of this work is to correlate and estimate the diffusion coefficient through dimensionless numbers, i.e., Schmidt and Prandtl. This work tries to reveal the importance of reforming and electrochemical reactions on these dimensionless numbers in active and inactive zones. In addition, the effects of inlet velocity (Re number), steam-to-carbon ratio (S/C) of inlet flow, current density, and porosity were investigated to disclose their importance on diffusion phenomena. A lattice Boltzmann method is used for numerical simulation of diffusion phenomenon in porous media of anode. Our results show that the Schmidt and the Prandtl numbers could be used for high precision estimation of the diffusion process in SOFC. It is also found that the molar ratio variation in hydrogen and water is highly effective since their diffusion characteristics are significantly different from other gases. By changing in operating parameters, the variation in the Prandtl number is much greater than the reforming reactions due to electrochemical reactions. Our results indicate that the Schmidt number of hydrogen increases by 53%, and the Prandtl number decreases about 45% at the center of SOFC when the porosity decreases about 25%.

Automated summary

This study utilized the lattice Boltzmann method to investigate diffusion phenomena in SOFC, focusing on estimating diffusion coefficients through dimensionless numbers and exploring the impacts of inlet velocity, steam-to-carbon ratio, current density, and porosity on diffusion processes. Additionally, the study revealed the significant effects of molar ratio variations in hydrogen and water, as well as the importance of changes in operating parameters on the Prandtl number.