Developing and Fully Developed Non-Newtonian Fluid Flow and Heat Transfer Through Concentric Annuli

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Mohammad Sefid ◽  
Ehsan Izadpanah
Keyword(s):  
Heat Transfer ◽  
Power Law ◽  
Convection Heat Transfer ◽  
Channel Length ◽  
Laminar Flows ◽  
Rheological Parameter ◽  
Power Law Fluid ◽  
Thermal Boundary Conditions ◽  
Flow And Heat Transfer ◽  
Power Law Index

Developing and fully developed laminar flows of power law fluid with forced convection heat transfer through a concentric annular duct are numerically analyzed. The results are presented for the following ranges: 0.2 ≤ n ≤ 1.8 (power law index), 10 ≤ Re ≤ 1000 (Reynolds number), and r* = 0.2, 0.5, 0.8 (aspect ratio). In addition, the influences of different thermal boundary conditions on the thermal performance are delineated. The effects of rheological parameter on the developing length, friction factor, temperature distribution, velocity profile, and Nusselt number along the channel length are investigated. The results are compared with earlier research and excellent agreement was observed.

scholarly journals Slip-Flow and Heat Transfer in a Porous Microchannel Saturated with Power-Law Fluid

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yazan Taamneh ◽  
Reyad Omari
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Skin Friction ◽  
Knudsen Number ◽  
Power Law ◽  
Slip Flow ◽  
Darcy Number ◽  
Power Law Fluid ◽  
Flow And Heat Transfer ◽  
Power Law Index

This study aims to numerically examine the fluid flow and heat transfer in a porous microchannel saturated with power-law fluid. The governing momentum and energy equations are solved by using the finite difference technique. The present study focuses on the slip flow regime, and the flow in porous media is modeled using the modified Darcy-Brinkman-Forchheimer model for power-law fluids. Parametric studies are conducted to examine the effects of Knudsen number, Darcy number, power law index, and inertia parameter. Results are given in terms of skin friction and Nusselt number. It is found that when the Knudsen number and the power law index decrease, the skin friction on the walls decreases. This effect is reduced slowly while the Darcy number decreases until it reaches the Darcy regime. Consequently, with a very low permeability the effect of power law index vanishes. The numerical results indicated also that when the power law index decreases the fully-developed Nusselt number increases considerably especially, in the limit of high permeability, that is, nonDarcy regime. As far as Darcy regime is concerned the effects of the Knudsen number and the power law index of the fully-developed Nusselt number is very little.

Non-Newtonian power-law fluid flow and heat transfer computation across a pair of confined elliptical cylinders in the line array

2012 ◽  
Vol 171-172 ◽  
pp. 67-82 ◽  
Author(s):  
Amir Nejat ◽  
Ehsan Mirzakhalili ◽  
Abbas Aliakbari ◽  
Mohammad S. Fallah Niasar ◽  
Koohyar Vahidkhah
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Power Law ◽  
Power Law Fluid ◽  
Flow And Heat Transfer ◽  
Line Array ◽  
Elliptical Cylinders

Augmentation of Pure Mixed Convection Heat Transfer in a Non-newtonian Power-law Fluid Filled Lid-driven Trapezoidal Cavity with Double Rotating Cylinders

2021 ◽  
Author(s):  
Hasib Ahmed Prince ◽  
Didarul Ahasan Redwan ◽  
Enamul Hasan Rozin ◽  
Sudipta Saha ◽  
Mohammad Arif Hasan Mamun
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Numerical Investigation ◽  
Power Law ◽  
Convection Heat Transfer ◽  
Cavity Surface ◽  
Rotating Cylinders ◽  
Power Law Fluid ◽  
Driven Cavity

Abstract In this study, a numerical investigation on mixed convection inside a trapezoidal cavity with a pair of rotating cylinders has been conducted. Three different power-law fluid indexes (n = 1.4, 1.0, and 0.6) have been considered to model different sets of non-Newtonian fluids. Four separate cases are considered dependent on the rotation orientation of the cylinders within the cavity. In the first two cases, the cylinders rotate in the same direction, i.e., both counter-clockwise (CCW), and both clockwise (CW), whereas, in the other two cases, cylinders rotate in opposite directions (CW-CCW and CCW-CW). Simulations have been carried out over a broad range of Reynolds number (from 0.5 to 500) and angular speeds (a dimensionless value from 0 to 10). The average Nusselt number values at the isothermal hot inclined cavity surface are determined to evaluate heat transfer performance in various circumstances. Streamlines and isotherm contours are also plotted for better understandings of the effects of different cases for various parameters on thermal and fluid flow fields. It is found that the Nusselt number varies non-linearly with different angular speeds of the cylinders. The combined effect of the mixing induced by cylinder rotation and viscosity characteristics of the fluid dictates the heat transfer in the system. Predictions from the numerical investigation provide insights onto the sets of key parametric configuration that have dominant influence on the thermal performance of lid driven cavity with double rotating cylinders.

Numerical Simulation of Natural Convection Heat Transfer on Microencapsulated PCM Slurries

2011 ◽  
Vol 84-85 ◽  
pp. 279-283
Author(s):  
Yan Lai Zhang ◽  
Zhong Hao Rao ◽  
Shuang Feng Wang ◽  
Hong Zhang ◽  
Li Jun Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Power Law ◽  
Fluid Model ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Fluid Behavior ◽  
Power Law Index ◽  
Rayleigh Benard

A numerical investigation on natural convection heat transfer in a 2-dimensional enclosure heated from below has been conducted with microencapsulated phase change material (PCM) slurries. The microencapsulated PCM slurry exhibits pseudoplastic non-Newtonian fluid behavior and has a peak value in the specific heat capacity. The viscosity of the slurry is assumed to follow the Ostwald-de Waele power law fluid model with the power-law index n and the consistency coefficient K. Both dynamic and heat transfer characteristics are discussed on Rayleigh-Bénard natural convection. Characteristics on natural convection heat transfer have been numerically investigated for different value of the width-height aspect ratio of the enclosure. According to the comparison of the two kinds of fluid with PCM and without PCM, the start of natural convection is earlier for the fluid with PCM.

Flow Inertia and Heat Transfer in Suddenly Expanding Annular Shear-Thinning Flows

2017 ◽  
Author(s):  
Khaled J. Hammad
Keyword(s):  
Heat Transfer ◽  
Power Law ◽  
Shear Thinning ◽  
Heat Transfer Augmentation ◽  
Flow And Heat Transfer ◽  
Prandtl Numbers ◽  
Power Law Index ◽  
Annular Pipe ◽  
Flow Inertia ◽  
The Impact

The impact of flow inertia on flow and heat transfer in suddenly expanding annular pipe flows of a shear-thinning non-Newtonian fluid is studied within the steady laminar flow regime. The equations governing conservation of mass, momentum, and energy, along with the power-law constitutive model are numerically solved using a finite-difference numerical scheme. The influence of inflow inertia, annular-nozzle-diameter-ratio, k, power-law index, n, and Prandtl numbers, is reported for: Re = {50, 100}, k = {0, 0.5}; n = {1, 0.6}; and Pr = {1, 10, 100}. Heat transfer augmentation, downstream the plane of expansion, is only observed for Pr = 10 and 100. The extent and intensity of recirculation in the corner region, increases with inflow inertia. Higher Reynolds and Prandtl numbers, power-law index values, and annular diameter ratios, in general, reflect a more dramatic heat transfer augmentation downstream of the expansion plane.

scholarly journals Non-Newtonian Power-Law Fluid Flow and Heat Transfer over a Non-Linearly Stretching Surface

2012 ◽  
Vol 03 (05) ◽  
pp. 425-435 ◽  
Author(s):  
Kerehalli Vinayaka Prasad ◽  
Seetharaman Rajeswari Santhi ◽  
Pampanna Somanna Datti
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Power Law ◽  
Stretching Surface ◽  
Power Law Fluid ◽  
Flow And Heat Transfer
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