Unsteady heat transfer from a reservoir fluid by employing metal foam tube, helically tube and straight tube: A comparative experimental study

The main purpose of this study is to experimentally investigate the transient heat transfer from a fluid stored inside a closed reservoir. Different cooling methods, i.e. the use of metal foam embedded tube, helical tube, and a straight tube, are used and compared for heat transfer from the fluid reservoir. CuO/water nanofluid in various volume fractions in the range of 0–0.2 (w/v) are also employed as cooling fluid. The experimental data shows a heat transfer enhancement of 42% and 45% for helical tube and metal foam tube respectively, as compare with the straight tube by using 0.2% (w/v) Cuo/water nanofluid. The experiments indicate that combination of the two presenting methods (metal foam/helical shape and nanofluids) has a significant capability to enhance the heat transfer rate. Finally, two correlations between Rayleigh number and non-dimensional heat flux are presented for the straight and porous tubes.