Appropriate position of porous insert in a heat exchanger by thermohydraulic analysis.

This paper presents numerically an appropriate position of a porous insert to get a better thermohydraulic performance from a porous heat exchanger. The simulation is based on the Darcy-Brinkman-Forchheimer model in the porous field. Two-dimensional continuity, momentum, and energy equations with incompressible, laminar, steady assumptions have been solved using a finite volume approach. The analysis is performed for different values of porous layer thickness, length, and porosity at a fixed value of Reynolds number (Re = 100) and thermal conductivity ratio (Rc = 5). The results showed that there is about a 48% and 13% reduction in pressure drop and Nusselt number, respectively, by decreasing horizontal porous substrate thickness from 1 to 1/2 for δv = 1/3 at ε = 0.7. As a result, the pressure drop reduces considerably with a reasonable reduction in heat transfer rate by decreasing horizontal porous substrate thickness from 1 to 1/2. [ABSTRACT FROM AUTHOR]