Nanoliquid film flow due to a moving substrate and heat transfer
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Nanoliquid film flow due to a moving substrate and heat transfer Mustafa Turkyilmazoglu1,2,a 1 Department of Mathematics, Hacettepe University, 06532-Beytepe Ankara, Turkey 2 Department of Medical Research, China Medical University Hospital, China Medical University, Taichung,
Taiwan Received: 10 February 2020 / Accepted: 26 September 2020 © Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The present work analyzed the flow and heat transfer of the nanoliquid film flow over a moving inclined substrate. The motion of nanoparticles is induced by the action of both the gravitational force as well as the substrate movement. The hydrodynamic and thermal layers developing along the channel with a constant film thickness are resolved analytically. The corresponding pressure distribution, velocity field, temperature field and the physical quantities of wall shear stress as well as wall heat transfer rate are formulated in closedform expressions. Seven different types of nanofluids are accounted for. Thermophysical properties of these particles enable us to visualize the flow and thermal development of the nanoliquid films in terms of the clean base fluid by the help of the defined shape factors. The considered mathematical model is validated against the available data in cases of special flow configurations. The carbon nanotubes are shown to have the highest heat transfer rates as compared to the other nanoparticles. On the other hand, the film thickness is much reduced and the wall shear is much amplified in the presence of silver nanoparticles.
1 Introduction Investigation of film flow development over flat stationary or moving inclined surfaces is one of the significant fluid mechanics problems. Many industrial and technological applications involve the film flow across moving vertical, horizontal, or slanted flat planes in several draining, coating, wetting, biological flows and solar cells [1–9]. The current analysis focuses on the development of film flow and the resulting heat transfer phenomena due to a moving inclined substrate when seven different nanoparticles [10] are accounted for across the developing liquid film. After the pioneering study of falling liquid films conducted by Nusselt in [11], there is now a substantial literature on the film flow over different geometries [12]. It was found by the lubrication approximation that the inclination angle modifies the complete wetting of a thin liquid film flowing down an inclined plane [13]. The film condensation phenomenon through horizontal microchannels was analyzed in [14]. How the film thickness develops over a vertical microchannel was studied in [15]. The flow of a liquid film in a channel with a bottom heater placed was analyzed in [16], and when the liquid Reynolds number is high,
a e-mail: [email protected] (corresponding author)
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Eur. Phys. J. Plus
(2020) 135:781
the convective heat transfer mechanism was found to be dominant. [17] studied th
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