The reaction rate for a wall surface reaction
 

Hello Ansys experts,

I am modelling a wall surface reaction. Consider the chemical reaction ongoing on a surface is A (species in fluid) + B (site species) --> C (solid species);

If I understand correctly, Ansys Fluent computes the reaction rate by R=k*c(A)*c(B), where k is the reaction constant, c(A) is the molar concentration in fluid in the unit [kmol/m^3], and c(B) represents the site density in the unit [kmol/m^2]. Neither the backward reaction nor coverage dependence was considered in this context.

k and c(B) are both just inputs from me, and they are not changing throughout the simulation period if I understand correctly. Notice that the temperature exponent and activation energy for reactions are both zero in the current simulation.

My question is

how Ansys Fluent determines c(A). Is it the molar concentration at the cell adjacent to the reaction surface?
If my understanding above is correct?
Thank you and regards