4.8 User-Accessible Functions for the Solid Oxide Fuel Cell With Unresolved Electrolyte Model

You can directly incorporate your own formulations and data for the properties of the solid oxide fuel cell model using the constit.c source code file.

The following listing represents a description of the contents of the constit.c source code file:

• real Nernst (real sp_a[], real sp_c[], real P_a, real P_c, real T_a,
  real T_c, real *DNDY): Returns the Nernst potential using Equation  3.4-8.

• real Activation (real Y[], real P, real T, real i, real i_0,
  real alpha_a, real alpha_b, int species, real *dA_di): Returns the activation overpotential by solving Equation  3.4-14.

• real Resistivity (real T): Returns the electrolyte resistance (either a constant value, or computed using Equation  4.4-1).

• real Leakage_Current_Density (real T): Returns the leakage current density specified in the SOFC Model dialog and can be overwritten as a function of temperature.

• real Solve_Butler_Volmer_NR (real i, real i0, real A, real B,
  real *detadi);: Returns the activation overpotential by solving Equation  3.4-14.

• real CONDUCTIVITY_CELL(cell_t c, Thread *t): Returns the cell conductivity value used in the Electric Field tab of the SOFC Model dialog. This function can be overwritten to look up the conductive zone group ID (1 through 5). A conditional statement allows you to perform various tasks for respective conductive zones. For non-conductive zones, this function returns a value of 0.

• real CONTACT_RESIST_FACE (face_t f, Thread *t): Returns the contact resistance value used in the Electric Field tab of the SOFC Model dialog. This function can be overwritten to look up the contact resistance group ID (1 through 3). A conditional statement allows you to perform various tasks for respective contact resistance surfaces. For non-contact resistance surfaces, this function returns a value of 0.

• real h2_co_split_func(cell_t c_an, Thread *t_an): Returns the $H_2$/ $CO$ split factor defined in Equation  3.5-9. This can be overwritten as needed to define your own split factor.