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

Abstract

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 1.10 m length, 16 mm, and 14 mm outside and inside diameter, respectively. While, the outer PVC pipe is 1 m length, 31 mm, and 27 mm outside and inside diameter, respectively. The inner pipe has been filling with 3 mm 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 flow-rates are in the range of (2-5) Lpm and 10 Lpm 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 flow-rates increase. It was observed that effectiveness increases as increase of flow-rate and nanofluid concentrations.