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In this study, the catalytic partial oxidation of methane is numerically investigated using an unstructured, implicit, fully coupled finite volume approach. The nonlinear system of equations is solved by Newton's method. The catalytic partial oxidation of methane over rhodium catalyst in a coated honeycomb reactor is studied three-dimensionally, and eight gas-phase species (CH4, CO2, H2O, N2, O2, CO, OH and H2) are considered for the simulation. Surface chemistry is modeled by detailed reaction mechanism including 38 heterogeneous reactions with 20 surfaceadsorbed species for the Rh catalyst. The numerical results are compared with experimental data and good agreement is observed. Effects of the design variables, which include the inlet velocity, methane/oxygen ratio, catalytic wall temperature, and catalyst loading on the cost functions representing methane conversion and hydrogen production, are numerically investigated. The sensitivity analysis for the reactor is performed using three different approaches: finite difference, direct differentiation and an adjoint method. Two gradient-based design optimization algorithms are utilized to improve the reactor performance. 1

A fully coupled numerical model for solid and fluid phases is developed to investigate the performance of catalytic reforming reactors. The transport of mass, momentum, energy and species in a reforming reactor are simultaneously solved using a three dimensional fully implicit unstructured finite volume approach. The nonlinear system of equations is solved by Newton’s method. Eight gas-phase species (CH4, CO2, H2O, N2, O2, CO, OH and H2) are considered for the simulation. The surface chemistry is modeled by detailed reaction mechanisms including 38 heterogeneous reactions with 20 surface-adsorbed species for rhodium catalyst and solved using the mean-field approximation model to obtain the surface convergence and reaction rates. The numerical results are compared with the experimental data and good agreement is observed. The simulation is performed for two different honeycomb-structured reactors. The governing equations for fluid and solid regions of the monolith are simultaneously solved with considering the catalytic combustion at their interface. The performance of the reforming reactor is numerically studied.

SOFC single cell was fabricated by using cost effective and simple methods like tape casting and screen printing. Anodic and anodic active layer and electrolyte layer were made by tape casting method. Properties and characterization of the cell was examined. Results showed fabricated cell has good microstructure and its performance that comparable with the other SOFC.

The following study investigates a 3-dimensional numerical model for the heat/mass and charge transfer simulation of a counter-flow planar solid oxide fuel cell to predict and evaluate its performance. The main emphasis in developing present model is to use for design and achieving optimized geometrical and effective parameters. This model can be used for calculation of thermal stresses and the structural design of the cell. Three dimensional transport equations are solved using computational fluid dynamics to simulate the flow field and to calculate species and temperature distribution in the computational domain. All ohmic, thermodynamic and electrochemical heat sources are taken in to account. Mass sources are calculated using the electrochemical reaction of hydrogen. Also the 3-D charge transfer equations are solved to predict the electrical potential distribution in the cell body and current collectors considering three kinds of polarization (ohmic, activation and concentration). To evaluate the model capabilities the results of the present study are compared with the experimental data and its accuracy is analyzed.

SOFC single cell was fabricated by using two simple and most frequently methods: tape casting and screen printing. Anodic and anodic active layer was made by tape casting method and screen printing method was used to fabricate electrolyte and cathode layer. Properties and performance of the cell were examined and compared with commercial cells. Results showed that fabricated cell has good properties and its performance is comparable with commercial one.