Improving thermal performance using Al2O3-water nanofluid in a double pipe heat exchanger filling with porous medium

A double pipe heat exchanger is significant device for many industrial applications. In this paper, an experimental study using both porous media and nanofluid to enhance heat transfer in a double pipe heat exchanger is performed. The test rig has been fabricated with inner copper pipe of 1.10m length, 16mm and 14mm outside and inside diameter respectively. While, the outer PVC pipe is 1m length, 31mm and 27mm outside and inside diameter respectively. The inner pipe has been filling with 3mm diameters of steel balls porous media. The experimental tests were performed utilizing alumina nanofluid (Al2O3/water) with two volume concentrations 0.5% and 1%. The volume flowrates are in the range of (2-5) liter/min and 10 liter/min through inner and outer pipe respectively. It was conducted with a constant 28°C inlet temperature of cold fluid flow inside the inner pipe and 50°C inlet temperature of hot fluid flow inside the outer pipe. Results indicated that the heat transfer enhanced as nanofluid volume concentrations and volume flowrates increase. It was observed that Effectiveness increases as increase of flowrate and nanofluid concentrations.