The CFX 4.4 code has been utilized to simulate the thermal field in periodic geometries subjected to uniform wall temperature boundary conditions. The problem is of great interest for compact heat exchanger development where complicated repetitive geometries are invariably utilized to augment the heat exchange surface. In presence of uniform wall temperature no periodic thermal field exist, therefore a proper non dimensional temperature has been defined leading to a new periodic boundary condition implemented in the CFX 4.4 code by means of the user Fortran subroutines. The extended code has been tested with some typical problems in forced convection in periodic domains with two and three dimensional geometries. The results obtained demonstrate the correctness of the adopted approach along with the capability of the commercial code CFX 4.4 to be adapted to the users demands.
