On Fri, May 10, 2013 at 2:11 AM, Frederic Durodie < frederic.duro...@googlemail.com> wrote:
> Dear FiPy users and developers, > > could you help me with how to implement a thermal contact, hc > [W/(m^2.K)], between two regions : so there is like a discontinuity in > the temperature between the two regions. > > In some cases I could implement it as a thin layer, dx [m], with a given > thermal diffusion coefficient, lambda [W/(m.K)], such that hc = > lambda/dx. > > However in some cases this distords the geometry somewhat and moreover > the results seem to depend rather strongly on the details of the mesh. > So, I was wondering if that contact could be included somehow in a sort > of BC. > > In the example below I have a thermal contact of hc = 1 kW/(m^2.K) > between two slabs (of length L/2) of good thermal conductors K = 200 > W/(m.K). On side is held to 0 C while on the other side a power flux Ps > = 1 kW/m^2 is applied. > > The temperature jump theoretically should be Ps/hc = 1 K (deg C) for > stationary conditions. > I believe the correct diffusion coefficient across the face that approximates a thin layer is D = Kc * (1 / (epsilon + (1 - epsilon) * D_ratio)) where D_ratio = Kc / 2 * (1 / K1 + 1 / K2) and epsilon = dx / cellSize I implemented this for a 1D problem and it seems to give the correct jump (see http://pastebin.com/qB0XgceL). I set K1 and K2 to just be K in the script to simplify. Cheers -- Daniel Wheeler
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