Search Results (3)

Several industrial fields require mixing and mechanical agitation processes. This operation is mainly used to enhance heat and mass transfer inside stirred tank systems and improve the degree of homogeneity to obtain a high-quality final product. The main goal of this research paper is to analyze the thermal and hydrodynamic behavior of non-Newtonian nanofluid (Bingham–Papanastasiou–Al₂O₃) inside a symmetrically stirred tank. A 3D numerical study has been conducted for a stationary laminar flow inside a symmetric cylindrical vessel under influencing parameters, including the inertia parameter ($Re=1, 20, 100$) and the volume fraction of nanoparticles ($\mathsf{Ø}=0.02, 0.06, 0.1$) with different geometric configurations, has been introduced into the stirring system. According to the findings, with high inertia ($Re=100$), the heat transfer inside the stirred tank is enhanced. Furthermore, increasing the nanoparticle fraction volume had a significant impact on the acceleration of heat transfer along the stirred vessel. It has been also found that the geometric configuration of an anchor with added arm blade (Case 2) is more efficient compared with the rest of the anchor agitator. Full article

This study investigated the flow and heat transfer of sodium alginate-based hybrid nanofluids with a stretching/shrinking surface. The heat source/sink, Joule heating, inclined magnetic field, and thermal radiation influences are also examined in the designed model. The mixers of non-magnetic and magnetic nanoparticles are utilized, such as $Cu$ and $F{e}_3{O}_4$. The Casson fluid model is applied to determine the viscoplastic characteristics of sodium alginate (SA). The necessary governing SA-based hybrid nanofluid flow equations are solved analytically by hypergeometric function. SA-based hybrid nanofluid velocity, temperature, skin friction, and Nusselt number results are discussed in detail with various pertinent parameters, such as radiation, heat source/sink, inclined angle, magnetic field, Eckert number, and Casson parameters. It is noted that the dimensions of both $Cu$ and $F{e}_3{O}_4$ hybrid nanoparticles and Casson parameters are minimized by the momentum surface layer thickness. The magnetic field, radiation, heat source and Casson parameters serve to enhance the thermal boundary layer thickness. Finally, the current result was verified with previously published works. Full article

The addition of nanoparticles to liquid media can improve thermomechanical properties of dispersants. This ability gives rise to the development of multiple applications of nanofluids (NF) in branches so different as electronic and photonic devices or cosmetic industry. Logically, these applications require a good control of heat transfer and flow properties. Moreover, if we consider the necessity to optimize industrial processes in which NF take part, it is necessary to obtain possible relationships between both physical mechanisms. Specifically, in this work, a study about thermal conductivity and rheological behavior of fumed silica suspensions in polypropylene glycol (PPG400) and polyethylene glycol (PEG200) was performed. The study of these two suspensions is interesting because the flow behaviors are very dissimilar (while the fumed silica in PEG200 suspension is viscoplastic, the fumed silica in PPG400 suspension shows shear-thickening behavior between two shear-thinning regions), despite the addition of fumed silica producing similar enhancement of the relative thermal conductivity in both liquid phases. The more outstanding contribution of this work lies in the combination of rheological and conductivity measurements to deepen in the understanding of the heat transfer phenomenon in NF. The combination of rheological together with thermal conductivity measurements have permitted establishing the mechanisms of liquid layering and aggregate formation as the more relevant in the heat transfer of these silica fumed suspensions. Full article