1. I compute two-step reactions. 4 POCl3 + 3 O2 â†' 2 P2O5 + 6 Cl2 2 P2O5 + 5 Si â†' 4 P + 5 SiO2 My data for calculation the reaction rate are : "pre-exponential factor : 1e+15", "activation energy：1000" and "temperature exponent：2.44"。 （are these values too large?）. But FLUENT says "Error: Gauss_Elimination: singular matrix. Error Object: () ". What's wrong with my two-step reactions?

2. (1) For species transport, how can I search the data of Lennard-Jones（L-J）.

Does anybody have any recommend? (2) First, "MATERIAL TYPE" for fluid, I give all fluid properties to be constant.

Second, "MATERIAL TYPE" for mixture, I set "MASS DIFFUSIVITY" to "KINETIC THEORY".

Then, unlikely before fluid properties option will appear "L-J Characteristic Length" and "L-J Energy Parameter". Why do they appear ??

Are "L-J Characteristic Length" and "L-J Energy Parameter" calculated by FLUENT ?? If yes, which equation can be presented the computing process ??

can somebody give him some suggestion ?