LBM for heat transport in thin films

Hi all…
I am a new user and I would really appreciate your help. I was plotting temperature versus length of the film and was not able to get a temperature jump (which is a charateristic of ballistic regime…i.e., for higher Knudsen numbers) at the boundaries after solving the Boltzmann transport equation with relaxation time approximation in 1D with prescribed (constant) temperature boundary conditions. If there is anyone working on this type of problem and can help me out, that would be great.