scholarly journals Viscous Dissipation Effect in the Free Convection of Non-Newtonian Fluid with Heat Generation or Absorption Effect on the Vertical Wavy Surface

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Mehdi Moslemi ◽  
Kourosh Javaherdeh

The present article analyzes the effect of viscous dissipations on natural convection heat transfer. The power law model for non-Newtonian fluid with heat generation or absorption effect along a sinusoidal wavy surface with isothermal boundary condition is investigated. A simple coordinate transform is employed to map the wavy surface into a flat surface, and also, the fully implicit finite difference method is incorporated for the numerical solution. The findings of this study can help better understand the effect of parameters such as the Brinkman number, heat generation/absorption, wave amplitude magnitude, and generalized Prandtl number on convective heat transfer in dilatant and pseudoplastic non-Newtonian. Results show that as the Brinkman number increases, the amount of heat transfer decreases. This is physically justifiable considering that the fluid becomes warmer due to the viscous dissipation, decreasing its temperature difference with the constant temperature surface. Also, the effect of the power law viscosity index is surveyed. It is demonstrated that the magnitude of the local Nusselt number in the plane leading edge has the smallest quantity for pseudoplastic fluids compared to dilatant Newtonian fluids. Additionally, as the distance from the plane leading edge increases, the heat transfer declines.

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Wasim Ullah Khan ◽  
Muhammad Awais ◽  
Nabeela Parveen ◽  
Aamir Ali ◽  
Saeed Ehsan Awan ◽  
...  

The current study is an attempt to analytically characterize the second law analysis and mixed convective rheology of the (Al2O3–Ag/H2O) hybrid nanofluid flow influenced by magnetic induction effects towards a stretching sheet. Viscous dissipation and internal heat generation effects are encountered in the analysis as well. The mathematical model of partial differential equations is fabricated by employing boundary-layer approximation. The transformed system of nonlinear ordinary differential equations is solved using the homotopy analysis method. The entropy generation number is formulated in terms of fluid friction, heat transfer and Joule heating. The effects of dimensionless parameters on flow variables and entropy generation number are examined using graphs and tables. Further, the convergence of HAM solutions is examined in terms of defined physical quantities up to 20th iterations, and confirmed. It is observed that large λ1 upgrades velocity, entropy generation and heat transfer rate, and drops the temperature. High values of δ enlarge velocity and temperature while reducing heat transport and entropy generation number. Viscous dissipation strongly influences an increase in flow and heat transfer rate caused by a no-slip condition on the sheet.


1999 ◽  
Author(s):  
Khaled J. Hammad

Abstract The non-isothermal laminar flow of the Bingham non-Newtonian fluid through a sudden pipe expansion is investigated. The governing equations of conservation of mass, momentum and energy are solved using the finite-difference numerical technique. The effects of non-dimensional yield stress, Reynolds number, Prandtl number and Brinkman number on the flow and heat transfer characteristics are studied. The obtained results indicate the complex nature of the present non-Newtonian fluid flow and heat transfer problem and reveal new features not encountered in the case of Newtonian fluids.


1970 ◽  
Vol 46 (4) ◽  
pp. 451-456 ◽  
Author(s):  
K Bhattacharyya ◽  
MS Uddin ◽  
GC Layek ◽  
W Ali Pk

In this paper, we obtained solutions of boundary layer flow and heat transfer for two classes of viscoelastic fluid over a stretching sheet with internal heat generation or absorption. In the analysis, we consider second-grade fluid and Walter's liquid B. The governing equations are transformed into self-similar ordinary differential equations by similarity transformations. The flow equation relating to momentum is solved analytically and then the heat equation using the Kummer's function. The analysis reveals that for the increase in magnitude of viscoelastic parameter both the velocity and temperature for a fixed point increase for second-grade fluid and both decrease for Walter's liquid B. Due to increase in Prandtl number and heat sink parameter, the thermal boundary layer thickness reduces, whereas increasing heat source parameter increases that thickness. Key words: Boundary layer flow; Heat transfer; Viscoelastic fluid; Stretching sheet; Heat generation or absorption DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9590 BJSIR 2011; 46(4): 451-456


2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983358
Author(s):  
Hongyan Chu ◽  
Xuecong Lin ◽  
Ligang Cai

In the offset press, ink flows in the microchannel made of two rotating rollers that are in the state of squeezing and contacting. The ink flow characteristics are not only influenced by the viscous dissipation effect, but also change with the heat transfer. First, by summarizing the common viscosity–shear rate models of non-Newtonian fluid, the power law model was chosen for describing offset ink through rheometer measuring. Combined with the experimental data, the viscosity–temperature relationship of the offset ink was described by the Arrhenius’s law. Then, the temperature characteristics of the offset ink fluid in the microchannel were studied using the fluid simulation software FLUENT. The ink fluid temperature field model considering viscous dissipation and heat transfer was established, and the temperature distributions of the ink fluid inside the microchannel and at the exit and entrance were obtained. The influence of the feature size on the ink temperature was also researched. Finally, the ink temperature and flow characteristics were compared with that under the condition without heat transfer. We got the influence of feature size and heat transfer on the ink temperature characteristics. As the feature size is smaller, the ink temperature increase from the microchannel entrance to the exit, increases first and then decreases, and keeps invariant at last. The heat transfer makes the viscous dissipation weaken relatively and then the ink temperature decreases. In a word, the heat transfer enhances as the feature size decreases. The results provide reference for improving the printing quality of offset press.


AIChE Journal ◽  
1962 ◽  
Vol 8 (4) ◽  
pp. 542-549 ◽  
Author(s):  
M. J. Shah ◽  
E. E. Petersen ◽  
Andreas Acrivos

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