Heat transfer and fluid flow characteristics of tubular channel partially filled with grooved metal foams

The metal foam is a type of porous media that can be characterized by high porosity, tortuous flow paths, high strength to weight ratio and high thermal conductivity. Due to these features the metal foam is used in many engineering applications such as heat exchanges. Therefore, a new design of a circular pipe partially filled with a grooved metallic foam is proposed in order to improve the hydraulic and thermal performance, and consequently reduce the pumping power losses and the metal foam volume. In the current work, the non-Darcy laminar forced convection flow is considered under the thermal boundary condition of constant wall heat flux. The governing equations are solved using the finite volume method (FVM) with temperature-dependent water properties. The variable parameters are; the pitch of the helical grooves, the number of helical grooves and the aspect ratio (Ri: diameter ratio of the metal foam to the pipe). The results show that for Ri = 0.55, four helical grooves having two pitches provides the optimal increase in the Nu number (7%) and the PEC is around 1.21 with a reduction in the pumping power and the amount of the metal foam about 25% and 16.74%, respectively, at Re = 1000.