Thermal Conductivity as a function of temperature

Hi all,

I am trying to include thermal conductivity as a function of temperature in my model but its giving me error 'inconsistent unit'..let us say the function is
-1.27E-9*(T)^3+8.09E-6*(T)^2- 8.37E-3*(T)+22.72
here 'T' is the dependent variable in Heat Transfer module. I am creating a variable to implement this.
I try to put the unit of thermal conductivity (W/m.K) but it does't take.
any idea how do i implement it?

thanks in advance

Regards
--
Manoj