Use of streamwise periodic boundary conditions for problems in heat and mass transfer

Fully developed periodic boundary conditions have frequently been employed to effect performance calculations for heat and mass exchange devices. In this paper a method is proposed, which is based on the use of primitive variables combined with the prescription of slip values. Either pressure difference or mass flow rate may be equivalently prescribed. Both constant wall temperature (Dirichlet) and constant heat flux (Neumann) conditions mail be considered, as well as the intermediate linear (Robin) boundary condition. The example of an offset-fin plate-fin heat exchanger is used to illustrate the application. of the procedure. The mathematical basis by which the method may be extended to the consideration of mass transfer problems with arbitrary boundary conditions, and associated continuity, momentum, and species sources and sinks is discussed.