Evaluation of heat transfer augmentation and pressure drop by water/ethylene glycol nanofluid

The turbulent convective heat transfer behavior of CaCO3/TiO2/CuO nanocomposite dispersions in water/ ethylene glycol is investigated experimentally in horizontal pipe-lines at constant heat flux at various in the Reynolds number range of 2900-18200 at 30 degrees C, heat flux of 800 kW/m2, and nanocomposite concentration of 0.01-0.1 Vol. %. The results showed considerable enhancement of convective heat transfer using the nanofluids. The enhancement was particularly significant in the entrance region, and was much higher than that solely due to the enhancement on thermal conduction. The Nusselt number and friction factor at 0.1 vol. % is greater than that values of water/ethylene glycol about 34.5 % and 18.9 %, respectively. The pressure drop increased with the concentration more than 3.6 % and decreased thereafter. Also, heat transfer coefficient in rough pipe-lines was higher than that in smooth pipe-lines at the same Reynolds number and it enhanced as the diameter decreased. Eventually, the greatest thermal performance factor of the nanofluid was 1.28 at 0.1 vol. % and Reynolds number of 4800.

Automated summary

The study investigated the convective heat transfer behavior of CaCO3/TiO2/CuO nanocomposite dispersions in water/ethylene glycol, showing significant enhancement in convective heat transfer using nanofluids, particularly in the entrance region. The Nusselt number and friction factor were higher with nanocomposite concentration, and pressure drop increased initially before decreasing. Heat transfer coefficient was higher in rough pipe-lines compared to smooth ones, with the greatest thermal performance factor achieved at 0.1 vol. % and Reynolds number of 4800.