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FLUID DYNAMIC BEHAVIOR OF HEAT EXCHANGERS WITH ACTIVE CAVITIES: A NUMERICAL STUDY

Numerical simulations have been performed on a series of cavities (called active cavities here) with a peculiar, purpose-fitted geometry, located on the external surface of tubular heat exchanger passages and on one side of the active wall in a flat plate heat exchanger. An incompressible fluid with a flow Reynolds number of 42,000 was considered and three turbulence models were compared: k- k , Spalart--Allmaras and large eddy (LES). The purpose of the cavities is to increase the heat transfer on the surface on which they are applied: some limited comparisons with an independent set of experimental data are also presented.