This paper proceeds numerical investigation on forced convective heat transfer of nanofluids in laminar flow inside a mini-channel with circular cross-section under constant heat flux boundary condition at walls. Nanofluid contains CuO nanoparticles with diameter of 50 nanometer in water base fluid. At the entrance of channel, profiles of uniform velocity & temperature prevail. In order to obtain fully developed profiles, geometry of problem considers as L/D = 100. Problem is solved by means of 4 different models, including Homogeneous and Dispersion models in both of constant and variable thermophysical properties through the finite-volume method. The temperature-dependent properties was used for the first time in nanofluids dispersion model. It was regarded in the presence of nanoparticles the heat transfer coefficient will be increased to some considerable extent and the heat transfer enhancement strongly depends on the volume concentration of nanoparticles and Peclet number. Also, comparison with experimental data and literatures' correlations is carried out which indicates the Dispersion model in both cases is more precise and Homogeneous model (single phase) underestimates the Nusselt number in constant thermo physical properties.
Numerical investigation of CuO nanoparticles effect on forced convective heat transfer inside a mini-channel: Comparison of different approaches
Jahanbin, Aminhossein;
2013
Abstract
This paper proceeds numerical investigation on forced convective heat transfer of nanofluids in laminar flow inside a mini-channel with circular cross-section under constant heat flux boundary condition at walls. Nanofluid contains CuO nanoparticles with diameter of 50 nanometer in water base fluid. At the entrance of channel, profiles of uniform velocity & temperature prevail. In order to obtain fully developed profiles, geometry of problem considers as L/D = 100. Problem is solved by means of 4 different models, including Homogeneous and Dispersion models in both of constant and variable thermophysical properties through the finite-volume method. The temperature-dependent properties was used for the first time in nanofluids dispersion model. It was regarded in the presence of nanoparticles the heat transfer coefficient will be increased to some considerable extent and the heat transfer enhancement strongly depends on the volume concentration of nanoparticles and Peclet number. Also, comparison with experimental data and literatures' correlations is carried out which indicates the Dispersion model in both cases is more precise and Homogeneous model (single phase) underestimates the Nusselt number in constant thermo physical properties.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.