Abstract. The knowledge of the dynamics of forced convection heat transfer in porous media is relevant in order to optimize the efficiency of geothermal installations in aquifers. In some applications groundwater is used directly as thermal fluid. The system uses one or several drilling holes to pump and deliver groundwater with a heat exchange system at surface (open loop). Other applications use vertical borehole heat exchangers without injection or extraction of groundwater (closed loop). In both systems the convection flow dynamics in porous media play an important role on the heat production. The present study is aimed at extending this thematic issue through heat transport experiments and their interpretation at laboratory scale. An experimental study to evaluate the dynamics of forced convection heat transfer in a thermally isolated column filled with porous medium has been carried out. The behavior of two porous media having different grain sizes and specific surfaces has been observed. The experimental data have been compared with an analytical solution for one dimensional heat transport for local non thermal equilibrium condition. The interpretation of the experimental data shows that, the heterogeneity of the porous medium affects heat transport dynamics causing a channeling effect which has consequences on thermal dispersion phenomena and heat transfer between fluid and solid phases limiting the capacity to store or dissipate heat in the porous medium.
Forced Convection Heat Transfer from a Heated Cylinder in an Axial Background Flow in a Porous Medium: Three Exactly Solvable Cases
