Convective heat transfer CFD analysis of forced flow through a half-stadium serpentine mini-channel at low Reynolds number

Spiral and serpentine channels are a very interesting solution to enhance heat transfer in small or miniaturized heat exchangers. In order to properly design these devices, of course, it is essential having a good knowledge of heat transfer characteristics of forced flow through this kind of ducts. However, the data base in open literature is rather lacking being investigations concerning flow mainly restricted to Dean number less than 500 and specific geometric parameters. In order to overcome these limits, a CFD analysis of a laminar forced flow through serpentine mini-channels has been started using a commercial code at finite volumes, namely Ansys Fluent. In this paper, after discussing the preliminary CFD analysis carried out on a straight pipe to tune the tool, we present the results on a flow through a half- stadium serpentine mini-channel with Reynolds number ranging between 200 and 2000. As thermal boundary conditions, a uniform wall temperature is assumed on the flat wall of the half-stadium duct, whereas the others are adiabatic. Finally, simultaneously developing flow condition is adopted. Heat transfer performances and pressure drops have been compared with ones in the straight tube, with the same length and hydraulic diameter as the serpentine duct. The results show heat transfer capability increases due to the presence of curvature as well as an earlier transition from laminar to turbulent flow.