It is essential to investigate the appropriate model for simulating nanofluid flow for different flow regimes because, at present, most previous studies do not agree with each other. It was, therefore, the purpose of this study to present a Computational Fluids Dynamics (CFD) investigation of heat transfer coefficients of internal forced convective flow of nanofluids in a circular tube subject to constant wall heat flux boundary conditions. A complete three-dimensional (3D) cylindrical geometry was used. Laminar and turbulent flow regimes were considered. Three two-phase models (mixture model, discrete phase model (DPM) and the combined model of discrete and mixture phases) and the single-phase homogeneous model (SPM) were considered with both constant and variable properties. For the turbulent flow regime, it was found that the DPM with variable properties closely predicted the local heat transfer coefficients with an average deviation of 9%, and the SPM deviated from the DPM model by 2%. It was also found that the mixture and the combined discrete and the mixture phase model gave unrealistic results. For laminar flow, the DPM model with variable properties predicted the heat transfer coefficients with an average deviation of 9%.
Liles, David C.; De Villiers, J.P.R. (Johan); Kahlenberg, Volker(Springer, 2016-02)
Crystals of a silico-ferrite of calcium and aluminium (SFCA) and an Al-free SFC were
prepared from the melt by slow cooling of synthetically prepared mixtures and examined by
single-crystal diffraction methods. Both ...
Wild ginger, Siphonochilus aethiopicus, is a traditional remedy for the treatment of
allergic asthma and other conditions. Preparations include hot infusions of rhizomes
and steaming of the rhizomes and inhalation of the ...
Sungkapreecha, Chanita; Beily, Mark J.; Kressler, Jörg; Focke, Walter Wilhelm; Androsch, René(Elsevier, 2018-02)
The phase behavior of binary mixtures of non-crystallizable racemic poly (d, l-lactic acid) (PDLLA) and the mosquito-repellent/drug N,N-diethyl-3-methylbenzamide (DEET) was analyzed with respect to the effect of the polymer ...