Hi Alexander, I would suggest that we need a little more information about your problem to be as helpful as possible. Are you working in 1D or 2D? Are both the tube and the fluid included in your simulation domain, or just the tube?
The reason I ask is that the boundary conditions are designed to be applied at the external faces of your domain. For example, if your domain features a tube surrounded by a fluid, the boundary conditions should only pertain to the fluid (since the fluid is the only thing touching the boundary of your domain). If you want a flux that is calculated in every cell of your system, you'll get that by solving your heat equations. For that, you may want to try declaring "Heat" or "Temperature" to be your CellVariable instead of "Fluid" or "Tube". Again, with a little more information about your problem and your code we may be able to provide more detailed help. - Will Gathright Rensselaer Polytechnic Institute Department of Materials Science and Engineering On Wed, May 5, 2010 at 11:14 AM, Alexander Holbach <[email protected]> wrote: > > Hi, > I am using the PDE solver in a system. > But I have problems with my boundarys. The system shall simulate a heat > transfer from tube to Fluid. So I wrote two systems with two seperated PDE > solvers. > > I'd like to know how I may implement the following boundary condition over > the right and left faces: > the equations are: > > … > tube = CellVariable(name="temperature [C]", mesh=mesh,value = 0.) > tube.equation = (ImplicitDiffusionTerm(coeff=k_r)) > tube.equation.solve(var=tube, > boundaryConditions=boundaryConditionsWand, > solver=DefaultAsymmetricSolver(tolerance=1.e-100, iterations=10000)) > > … > and > … > > Fluid = CellVariable(name="temperature [C]", mesh=mesh,value = 0.) > Fluid.equation = ImplicitDiffusionTerm(coeff=k_fg)== > rho*cp*ExplicitUpwindConvectionTerm(coeff=((v_f,))) > Fluid.equation.solve(var=Fluid, > boundaryConditions=boundaryConditionsFluid, > solver=DefaultAsymmetricSolver(tolerance=1.e-100, iterations=10000)) > > and now I want to implement the boundary condition, that there is a Flux in > each mesh cell from the tube to the Fluid. > What I can write is: > … > > FixedFlux(faces=mesh.getFacesLeft(), > value=h_rf*a_rf*(tube(1,0,6000)-Fluid(1,0,6000))), > FixedFlux(faces=mesh.getFacesRight(), > value=h_rf*a_rf*(tube(1,0,6000)-Fluid(1,0,6000)))) > … > > but this is a fix Flux and I want that the Flux will be calculate in each > cell of the system. > > Is this possible? > > Thank for your help > Alexander > -- > GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! > Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01 > >
