udf electronic potential boundary.

shuqin

Hi,everybody I want to model a chemical reaction in which current is produced.I model the specie production and consumption by applying a mass source term and a specie source term in the cells adjacent to the reactive wall,and it works well.

then I define a UDS (the scalar represents the elctronic potential )to resolve a laplace equation since there current is produced in the chemical reaction. and it was OK to solve a laplace equation with one wall (the wall opposite to the reactive wall )electric potential given and the reactive wall current density given.

but ACCESS_VIOLATION Error came out when the time i want to define the electric potential as a function of the specie mole fractions at the reactive wall,the function is like this :

V=S1+S2*In(Y_H2/Y_H2O)

where S1 and S2 are constant value and Y_H2 Y_H2O denotes mole fractions of hydrogen and water vapor.

I calcaulate the part:In(Y_H2/Y_H2O)of the potential profile function with DEFINE_ON_DEMAND,since we could not get specie mass fraction of the boundary wall through F_YI(f,t,i),and I use the value of C_YI(c0,t0,i)as the specie mass fraction at the reactive wall to calculate the specie mole fraction and In(Y_H2/Y_H2O).

so where am I wrong?

and can someone tell me how to deal with it?