Investigation of heat transfer and pressure drop in a porous media with internal heat generation

Abstract

Heat transfer by forced convection of turbulent flow in a cylindrical channel composed of a porous medium with internally generated heat is studied experimentally in this paper. The pressure drop through the channel is determined experimentally and numerically. Steel spheres are used to form a porous channel and electromagnetic induction heating method is used to uniformly generate internal heating in these spheres. Dry air is used as the working fluid during cooling of the heated spheres. The length and inside diameter of the heated copper test section are 500 and 47 mm, respectively. The experiments are carried out for regimes of turbulent flow with Reynolds number based on the spheres diameter (Red), which ranges from 490 to 5490. The impact of various parameters, which include internal heat generation (Q), sphere diameter (d = 6, 8, 10, and 14 mm), and dry air inlet velocity, on heat transfer by forced convection are studied. The pressure drop data agree with the Newtonian prediction. The results show that decreasing porosity of the channel by 6% increases heat transfer by 38% approximately at the same Red, in the range of Red (750–3000). Increasing Red increases heat transfer at the same porosity. The maximum raise in Nusselt number is 20% with raising internal heat generation by 80% at the same porosity, and the pressure drop increases by 200% with decreasing porosity by 6% at the same Red, in the range of Red (750–3000). Increasing Red by 100% increases the pressure drop by 200% approximately at the same porosity, in the range of Red (1000–4000).

Keywords

• Porous media
• Induction heating
• Heat generation