hi, I have been trying to simulate the following problem(Tian and Karayiannis).

A square cavity(0.75x0.75x1.5m) has two isothermal vertical walls maintained at 50 c and 10 c,top and bottom (1.5x0.75) are made of steel(1.5mm) covered by polystyrene layer(100mm) and wood layer(100mm),the front and rear faces(0.75x0.75) are adiabatic.

The litreature says that it can be treated as two dimensional problem.

I succeeded in creating a 3d mesh that was one cell thick in the z-dir.(i.e) I created a square (0.75x0.75)in the xy plane and extruded it to one cell thickness in the z direction.

But im confused about the boundary condition! While i can specify the conditions for the isothermal walls,i am uncertain what boundary conditions to use for the conducting walls.Do i specify the front and rear(0.75x0.75)faces as symmetry planes?

i remenber having read in previous posts that someone had already worked on the same problem!I d be glad to get some ideas and a good explanation of symmetry plane boundary condition!

P.S :I have read the 'help' but im not able to relate the info given there to this problem.!

thanks and regards,

Dear Michelle,

The front and rear faces should be specified as symmetry planes if the problem is 2 dimensional.

For the top and bottom walls, you can calculate the overall thermal resistance of the steel/wood/polystyrene layer from their thermal conductivities and thickness. You can then apply a 'heat transfer coefficient and outside temperature' thermal boundary condition directly to the boundaries, without physically modelling these layers.

Regards,

Johnson

Hi Johnson...

Thanks a Lot..

Thats sorta clarified my point!!

regrds, Michelle