Experimental Study on the Performance of Gradient Pores Density Metal Foam in a Rectangular Channel

Various approaches are employed to enhance the heat transfer coefficient and Nusselt number inside the channels. One of the techniques employed for these enhancements is the utilization of porous media. In the current article, a practical investigation of forced convection heat transfer in a rectangular cross-section channel (0.05 x 0.1 m2) with 0.25 m length is conducted. A heater with a heat flux range (450-6000 W/m2) is imposed under a copper plate, and the other sides are covered by insulation layers. The air is considered as a working fluid with Re (600-2100). The test section is fully filled with gradient pores per inch (PPI) metal foam by taking three different pores densities PPI (10, 20, and 40 PPI) and studying its effects on the temperature of copper plate, the local heat transfer coefficient, average Nusselt number, pressure drop, friction factor, and the performance factor. Three cases were studied inside the channel: one empty case and two with gradient pore density case A (40-20-10) PPI and case B (10-20-40) PPI. The results showed that inserting the metal foam inside the channel improves h and Nu. Case B appeared the best of this improvement in h and Nu by 12% and 25%, respectively, compared with that in case A. While the friction factor was the same for two cases A and B. So, the performance factor in case B showed an improvement of around 25% and 50% in comparison to case A and the empty case, respectively.