Effects of variable fluid properties on the thin film flow of Ostwald-de Waele fluid over a stretching surface

An isothermal thin-film flow over a rotating plate has been simulated using the depth-averaged Eulerian Thin-Film modelling (ETFM) approach. The model setup is based on published experimental and numerical Volume of Fluid (VOF) CFD studies of the same problem to allow for model validation. A range of controlled film inlet heights and mass flow rates are explored together with varied plate rotational speeds ranging from a stationary plate (50rpm) to 200 rpm. While the VOF model has previously been shown to accurately reproduce film thickness, the Eulerian thin-film model is shown to provide predictions of comparable accuracy at a much lower computational cost. The model is also shown to be able to reproduce the film solution’s sensitivity to variations in fluid properties due to changes in inlet temperature. A full 3D domain has been used in this study and the ETFM model is also shown to be able to reproduce azimuthal film thickness variations and surface features similar to those previously observed in experiments.

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Thin film flow of an unsteady Maxwell fluid over a shrinking/stretching sheet with variable fluid properties

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-12-2017-0498 ◽

2018 ◽

Vol 28 (7) ◽

pp. 1596-1612 ◽

Cited By ~ 5

Author(s):

N. Faraz ◽

Y. Khan

Keyword(s):

Thin Film ◽

Differential Equation ◽

Boundary Layer ◽

Partial Differential Equation ◽

Stretching Sheet ◽

Film Flow ◽

Maxwell Fluid ◽

Thin Film Flow ◽

Content Type ◽

Fluid Properties

Purpose This paper aims to explore the variable properties of a flow inside the thin film of a unsteady Maxwell fluid and to analyze the effects of shrinking and stretching sheet. Design/methodology/approach The governing mathematical model has been developed by considering the boundary layer limitations. As a result of boundary layer assumption, a nonlinear partial differential equation is obtained. Later on, similarity transformations have been adopted to convert partial differential equation into an ordinary differential equation. A well-known homotopy analysis method is implemented to solve the problem. MATHEMATICA software has been used to visualize the flow behavior. Findings It is observed that variable viscosity does not have a significant effect on velocity field and temperature distribution either in shrinking or stretching case. It is noticed that Maxwell parameter has no dramatic effect on the flow of thin liquid fluid. It has been seen that heat flow increases by increasing the conductivity with temperature in both cases (shrinking/stretching). As a result, fluid temperature goes down when than delta = 0.05 than delta = 0.2. Originality/value To the best of authors’ knowledge, nobody has conducted earlier thin film flow of unsteady Maxwell fluid with variable fluid properties and comparison of shrinking and stretching sheet.

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Thin-film flow of Carreau fluid over a stretching surface including the couple stress and uniform magnetic field

Partial Differential Equations in Applied Mathematics ◽

10.1016/j.padiff.2021.100162 ◽

2021 ◽

pp. 100162

Author(s):

Muhammad Bilal ◽

Anwar Saeed ◽

Taza Gul ◽

Muhammad Rehman ◽

Amir Khan

Keyword(s):

Magnetic Field ◽

Thin Film ◽

Couple Stress ◽

Uniform Magnetic Field ◽

Film Flow ◽

Thin Film Flow ◽

Stretching Surface ◽

Carreau Fluid

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Nanofluids Thin Film Flow of Reiner-Philippoff Fluid over an Unstable Stretching Surface with Brownian Motion and Thermophoresis Effects

Coatings ◽

10.3390/coatings9010021 ◽

2018 ◽

Vol 9 (1) ◽

pp. 21 ◽

Cited By ~ 26

Author(s):

Asad Ullah ◽

Ebraheem Alzahrani ◽

Zahir Shah ◽

Muhammad Ayaz ◽

Saeed Islam

Keyword(s):

Thin Film ◽

Brownian Motion ◽

Film Flow ◽

Fluid Model ◽

Time Dependent ◽

Thin Film Flow ◽

Stretching Surface ◽

Fluid Parameter ◽

Homotopy Analysis ◽

Dependent Parameter

The current investigation is carried out on the thin film flow of Reiner-Philippoff fluid of boundary-layer type. We have analyzed the flow of thin films of Reiner-Philippoff fluid in the changeable heat transmission and radiation over a time-dependent stretching sheet in 2D. The time-dependent governing equations of Reiner-Philippoff fluid model are simplified with the help of transformation of similarity variables. To investigate the behavior of the Reiner-Philippoff fluid with variable stretching surface for different physical effects, we considered thermophoresis and Brownian motion parameters in the flow. The Homotopy Analysis Method is implemented in the reduced model to achieve a solution of the original problem. A numerical convergence of the implemented method is also analyzed. The behavior of temperature, velocity, and concentration profiles have been investigated with the variation of skin friction, Nusselt number, and Sherwood number. A comparative graphical survey is presented for the velocity gradient, under different parameters. An analytical analysis is presented for the time-dependent parameter over thin film flow. The results we obtained are better than the previously available results. For the survey, the physical representation of the embedded parameters, like, β depends on the stretching parameter ζ , and the Reiner-Philippoff fluid parameter ϵ are discussed in detail and plotted graphically. Prandtl number P r , Brownian motion parameter N b , thermophoretic number N t , and Schmidt number S c are presented by graphs and discussed in detail.

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Evaluation of Heat Irreversibility in a Thin Film Flow of Couple Stress Fluid on a Moving Belt

Advances in Mathematical Physics ◽

10.1155/2018/6237592 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6

Author(s):

Samuel O. Adesanya ◽

Ramosheuw S. Lebelo ◽

K. C. Moloi

Keyword(s):

Thin Film ◽

Couple Stress ◽

Film Flow ◽

Second Law Of Thermodynamics ◽

Entropy Generation Rate ◽

Thermodynamic Process ◽

Thin Film Flow ◽

Governing Equations ◽

Fluid Properties ◽

Adiabatic Surface

This article addresses the inherent heat irreversibility in the flow of a couple stress thin film along a moving vertical belt subjected to free and adiabatic surface. Mathematical analysis for the fluid-governing-equations is performed in detail. For maximum thermal performance and efficiency, the present analysis follows the second law of thermodynamics approach for the evaluation of entropy generation rate in the moving film. With this thermodynamic process, the interconnectivity between variables responsible for energy wastage is accounted for in the thermo-fluid equipment. Results of the analysis revealed the fluid properties that contribute more to energy loss and how the exergy of the system can be restored.

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