Discussion Forum

I'm using the Chemical reaction engineering module to model fluid flows with the TCS transport of concentrated species interface. Or the RFCS interface, reacting flow in porous media. I am attempting to use the chemistry interface to calculate the gas mixture properties.

I'm trying to use the chemistry interface to calculate the gas mixture properties; Specifically, the mixture dynamic viscosity, in addition to the thermal conductviity and heat capacity..
I can see how to get the specific heat capacity, and thermal conductivity of the mixture: I can enter a value for the property of each species, and then the software combines them into an effective mixture value.

But it seems impossible to get the dynamic viscosity (of a gas mixture without a solvent) unless I want to employ the relationships from kinetic gas theory (pg 51 of the user guide). I have the dynamic viscosity data of each species, relatively constant.

I would like to go to the individual species nodes and enter a (numerical) value for the dynamic viscosity of each gaseous species, but the software doesn't seem to want to let me do that..

I can see the variables defined in the [equation view] Chemistry node:
Its "chem.eta_speciesname1" and Its "chem.eta_speciesname2"

But I just can't see how to change / edit them?? Why COMSOL is so intent to block me from doing this? I can't seem to enter a user-defined value for the dynamic viscosity of the individual species...