scholarly journals Effect of Prandtl Number on Forced Convection in a Two Sided Open Enclosure Using Nanofluid

2012 ◽  
Vol 5 (1) ◽  
pp. 67-75 ◽  
Author(s):  
S. Parvin ◽  
R. Nasrin ◽  
M. A. Alim ◽  
N. F. Hossain
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Finite Element Method Simulation ◽  
Darcy Number ◽  
The Finite Element Method ◽  
Enhancement Of Heat Transfer ◽  
Average Temperature ◽  
Forced Convective Flow

Analysis of Prandtl number effect on forced convective flow and thermal field characteristics inside an open cavity with porous wavy isothermal wall using water-CuO nanofluid have been performed numerically. The upper and lower surfaces are of temperature Th. The fluid enters from left and exits from right with initial velocity Ui and temperature Ti. Governing equations are discretized using the Finite Element Method. Simulation is carried out for a range of Prandtl number, Pr (from 1.47 to 8.81) and wave amplitude A (from 0 to 0.15) while Reynolds number, Re =100; Darcy number, Da = 100 and solid volume fraction,  = 5%. Results are presented in the form of streamlines, isothermal lines, rate of heat transfer, average temperature of the fluid and velocity at mid-height of the channel for various Pr and A. Increasing Pr and lessening A causes the enhancement of heat transfer rate.© 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i1.9641          J. Sci. Res. 5 (1), 67-75 (2013)

Effects of uniform or non-uniform heating at bottom wall on MHD mixed convection in a porous cavity saturated by nanofluid

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Subramanian Muthukumar ◽  
Selvaraj Sureshkumar ◽  
Arthanari Malleswaran ◽  
Murugan Muthtamilselvan ◽  
Eswari Prem
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Transfer Rate ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Darcy Number ◽  
Bottom Wall ◽  
Uniform Heating ◽  
The Magnetic Field

Abstract A numerical investigation on the effects of uniform and non-uniform heating of bottom wall on mixed convective heat transfer in a square porous chamber filled with nanofluid in the appearance of magnetic field is carried out. Uniform or sinusoidal heat source is fixed at the bottom wall. The top wall moves in either positive or negative direction with a constant cold temperature. The vertical sidewalls are thermally insulated. The finite volume approach based on SIMPLE algorithm is followed for solving the governing equations. The different parameters connected with this study are Richardson number (0.01 ≤ Ri ≤ 100), Darcy number (10−4 ≤ Da ≤ 10−1), Hartmann number (0 ≤ Ha ≤ 70), and the solid volume fraction (0.00 ≤ χ ≤ 0.06). The results are presented graphically in the form of isotherms, streamlines, mid-plane velocities, and Nusselt numbers for the various combinations of the considered parameters. It is observed that the overall heat transfer rate is low at Ri = 100 in the positive direction of lid movement, whereas it is low at Ri = 1 in the negative direction. The average Nusselt number is lowered on growing Hartmann number for all considered moving directions of top wall with non-uniform heating. The low permeability, Da = 10−4 keeps the flow pattern same dominating the magnetic field, whereas magnetic field strongly affects the flow pattern dominating the high Darcy number Da = 10−1. The heat transfer rate increases on enhancing the solid volume fraction regardless of the magnetic field.

scholarly journals Hydrothermal and Entropy Investigation of Ag/MgO/H2O Hybrid Nanofluid Natural Convection in a Novel Shape of Porous Cavity

2021 ◽  
Vol 11 (4) ◽  
pp. 1722
Author(s):  
Nidal Abu-Libdeh ◽  
Fares Redouane ◽  
Abderrahmane Aissa ◽  
Fateh Mebarek-Oudina ◽  
Ahmad Almuhtady ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Natural Convection ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Hybrid Nanofluid ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Nanofluid Flow ◽  
The Magnetic Field

In this study, a new cavity form filled under a constant magnetic field by Ag/MgO/H2O nanofluids and porous media consistent with natural convection and total entropy is examined. The nanofluid flow is considered to be laminar and incompressible, while the advection inertia effect in the porous layer is taken into account by adopting the Darcy–Forchheimer model. The problem is explained in the dimensionless form of the governing equations and solved by the finite element method. The results of the values of Darcy (Da), Hartmann (Ha) and Rayleigh (Ra) numbers, porosity (εp), and the properties of solid volume fraction (ϕ) and flow fields were studied. The findings show that with each improvement in the Ha number, the heat transfer rate becomes more limited, and thus the magnetic field can be used as an outstanding heat transfer controller.

Coupled Free and Forced Convection Heat Transfer in a Porous Enclosure Saturated by Nanofluid with Irregular Temperature Distributions on Sidewalls

2017 ◽  
Vol 15 (6) ◽  
Author(s):  
M. Muthtamilselvan ◽  
S. Sureshkumar ◽  
Deog Hee Doh
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Amplitude Ratio ◽  
Solid Volume Fraction ◽  
Side Wall ◽  
Darcy Number ◽  
Total Heat Transfer ◽  
Phase Deviation

Abstract A two dimensional steady and laminar mixed convection flow in lid-driven porous cavity filled with Cu-water nanofluid is presented in this numerical investigation. The vertical side walls are considered with two spatially varying sinusoidal temperature distributions of different amplitude ratios and phase deviations while the horizontal walls are thermally insulated. The transport equations are solved using finite volume method on a uniformly staggered grid system. The variations of fluid flow, heat transfer, mid-plane velocity, and Nusselt number were discussed over a wide range of Richardson number $(Ri)$ , Darcy number $(Da)$ , porosity $(\epsilon)$ , amplitude ratio $(\epsilon_a)$ , phase deviation $(\phi)$ , and solid volume fraction $(\chi)$ . The results show that the total heat transfer rate increases on increasing Darcy number, amplitude ratio, and solid volume fraction with fixed $Ri$ . For $\phi=\frac{3\pi}{4}$ , the average Nusselt number gets its maximum value when the natural convection dominates. It is found that for $Ri =0.01$ and $1$ , the total heat transfer rate decreases on increasing porosity whereas for $Ri=100$ it is contradictory. It is also observed that the heat transfer is affected mainly on the right side wall where the phase deviation varies from $0$ to $\pi$ . But the effect of $\phi$ is not significant on the left side wall. The sinusoidal temperature distribution along the sidewalls gives better heat transfer rate than the uniform temperature.

scholarly journals MHD Free Convection and Entropy Generation in a Corrugated Cavity Filled with a Porous Medium Saturated with Nanofluids

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 846 ◽  
Author(s):  
Ali Chamkha ◽  
Fatih Selimefendigil
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Entropy Generation ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Darcy Number ◽  
Grashof Number ◽  
Triangular Wave ◽  
Flow Features

MHD free convection inside a triangular-wave-shaped corrugated porous cavity with Cu-water nanofluid is numerically studied with the finite element method. The influences of the Grashof number ( 10 4 ≤ Gr ≤ 10 6 ), Hartmann number ( 0 ≤ Ha ≤ 50 ), Darcy number ( 10 − 4 ≤ Da ≤ 10 − 1 ) and solid volume fraction of the nanoparticle ( 0 ≤ ϕ ≤ 0.05 ) on the convective flow features are examined. It is observed that increasing the Grashof number and Darcy number enhances the heat transfer, while the effect is opposite for the Hartmann number. As the corrugation frequency of the triangular wave increases, the local and averaged heat transfer rates decrease, which is more effective for higher values of Grashof and Darcy numbers. Normalized total entropy generation increases as the Darcy number and solid volume fraction of the nanoparticles increase and decreases as the Hartmann number increases both for flat and corrugated wall configurations.

Modeling Heat Transfer Enhancement of Ferrofluid (Fe3O4–H2O) Flow in a Microchannel Filled with a Porous Medium

2021 ◽  
Vol 10 (1) ◽  
pp. 31-44
Author(s):  
Bullo Hindebu Rikitu ◽  
Oluwole Daniel Makinde ◽  
Lemi Guta Enyadene
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Volume Fraction ◽  
Variable Viscosity ◽  
Darcy Number ◽  
Eckert Number ◽  
Viscosity Parameter ◽  
Number Increase ◽  
Permeable Walls ◽  
Nanoparticles Volume Fraction

Heat transfer characteristics and hydrodynamical properties of ferrofluid through microchannels with non-uniform permeable walls temperature and filled with porous media plays an important role in modern microfluidic applications, such as solar collectors, nuclear reactors, micro-electro-chemical cell transport, micro heat exchanging, microchip cooling, and electronic equipment. Therefore, this paper presents the investigation of ferrofluid (Fe3O4-H2O) heat transfer characteristics as well as hydrodynamical properties in a permeable microchannel with non-uniform permeable walls. The semi-discretization finite difference method is utilized to solve the highly non-linear partial differential equations that govern the momentum and energy equations. Accordingly, the numerical outcomes reveal that the ferrofluid velocity and temperature profiles indicate a rising trend as the pressure gradient parameter, the variable viscosity parameter, the Darcy number, the Eckert number, and Prandtl number increase. The Reynolds number, which is a suction/injection parameter, shows a contrary influence on the ferrofluid velocity and temperature whereas nanoparticles volume fraction and the Forchheimer constant show a decreasing effect on the ferrofluid velocity and temperature. The outcomes also depict that the coefficient of skin friction at the cold wall of the microchannel is larger for higher values of the nanoparticles volume fraction, the variable viscosity parameter, the Darcy number, and the Eckert number. Besides, the coefficient of skin friction at the hot wall rises with the Darcy number, and the Prandtl number. Furthermore, the heat transfer rate at both cold and hot walls of the microchannel increases as the variable viscosity parameter, the Darcy number, the Eckert number, and the Prandtl number increase. The nanoparticles volume fraction and Darcy number show a retarding effect on the heat transfer rate at both walls of the microchannel.

scholarly journals Mathematical Modelling of MHD Natural Convection in a Linearly Heated Porous Cavity

2021 ◽  
Vol 8 (1) ◽  
pp. 149-157
Author(s):  
Jino Lawrence ◽  
Vanav Kumar Alagarsamy
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Heat Flow ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Flow Analysis ◽  
Darcy Number ◽  
Magnetic Field Effects ◽  
Porous Cavity

A linear increase in thermal boundaries towards the bottom of the porous cavity is considered for numerical flow analysis on MHD natural convection. The two-dimensional square shaped cavity is filled with the Cu-water nanofluid. The dimensionless equations are considered to interpret the fluid and heat flow inside the cavity with respect to the desired boundaries. The governing equations are solved using the finite difference techniques. The relevant dimensionless parameters used in the present study are Rayleigh number, Darcy number, solid volume fraction of the nanoparticles and Hartmann number to obtain the flow fields. Heatline flows picturization techniques involved in the study analyze the heat flow inside the cavity. As the Rayleigh number and Darcy number increases, an increase in streamlines flow velocity and convection heat transfer is observed. Convective heat transfer is interrupted by increasing the applied magnetic field effects. An improvement in the heat transfer is noticed by increasing the solid volume fraction of the particles.

scholarly journals A sensitivity study on carbon nanotubes significance in Darcy–Forchheimer flow towards a rotating disk by response surface methodology

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anum Shafiq ◽  
Tabassum Naz Sindhu ◽  
Qasem M. Al-Mdallal
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Biot Number ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Rotating Disk ◽  
Sensitivity Study ◽  
Basic Fluid ◽  
Walled Cnts

AbstractThe current research explores incremental effect of thermal radiation on heat transfer improvement corresponds to Darcy–Forchheimer (DF) flow of carbon nanotubes along a stretched rotating surface using RSM. Casson carbon nanotubes’ constructed model in boundary layer flow is being investigated with implications of both single-walled CNTs and multi-walled CNTs. Water and Ethylene glycol are considered a basic fluid. The heat transfer rate is scrutinized via convective condition. Outcomes are observed and evaluated for both SWCNTs and MWCNTs. The Runge–Kutta Fehlberg technique of shooting is utilized to numerically solve transformed nonlinear ordinary differential system. The output parameters of interest are presumed to depend on governing input variables. In addition, sensitivity study is incorporated. It is noted that sensitivity of SFC via SWCNT-Water becomes higher by increasing values of permeability number. Additionaly, sensitivity of SFC via SWCNT-water towards the permeability number is higher than the solid volume fraction for medium and higher permeability levels. It is also noted that sensitivity of SFC (SWCNT-Ethylene-glycol) towards volume fraction is higher for increasing permeability as well as inertia coefficient. Additionally, the sensitivity of LNN towards the Solid volume fraction is higher than the radiation and Biot number for all levels of Biot number. The findings will provide initial direction for future device manufacturing.

NUMERICAL SIMULATION OF MARANGONI MAGNETOHYDRODYNAMIC BIO-NANOFLUID CONVECTION FROM A NON-ISOTHERMAL SURFACE WITH MAGNETIC INDUCTION EFFECTS: A BIO-NANOMATERIAL MANUFACTURING TRANSPORT MODEL

2014 ◽  
Vol 14 (03) ◽  
pp. 1450039 ◽  
Author(s):  
O. ANWAR BÉG ◽  
M. FERDOWS ◽  
S. SHAMIMA ◽  
M. NAZRUL ISLAM
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Prandtl Number ◽  
Stream Function ◽  
Magnetic Induction ◽  
Body Force ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Convection Boundary Layer ◽  
Force Parameter

Laminar magnetohydrodynamic Marangoni-forced convection boundary layer flow of a water-based biopolymer nanofluid containing nanoparticles from a non-isothermal plate is studied. Magnetic induction effects are incorporated. A variety of nanoparticles are studied, specifically, silver, copper, aluminium oxide and titanium oxide. The Tiwari–Das model is utilized for simulating nanofluid effects. The normalized ordinary differential boundary layer equations (mass, magnetic field continuity, momentum, induced magnetic field and energy conservation) are solved subject to appropriate boundary conditions using Maple shooting quadrature. The influence of Prandtl number (Pr), magnetohydrodynamic body force parameter (β), reciprocal of magnetic Prandtl number (α) and nanofluid solid volume fraction (φ) on velocity, temperature and magnetic stream function distributions is investigated in the presence of strong Marangoni effects (ξ i.e., Marangoni parameter is set as unity). Magnetic stream function is accentuated with body force parameter. The flow is considerably decelerated as is magnetic stream function gradient, with increasing nanofluid solid volume fraction, whereas temperatures are significantly enhanced. Interesting features in the flow regime are explored. The study finds applications in the fabrication of complex biomedical nanofluids, biopolymers, etc.

scholarly journals Numerical Analysis of Nanofluids in Differentially Heated Enclosure Undergoing Orthogonal Rotation

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
H. Saleh ◽  
I. Hashim
Keyword(s):  
Heat Transfer ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Convection Heat Transfer ◽  
Staggered Grid ◽  
Governing Equations ◽  
Nanoparticles Concentration ◽  
Quantity Of Heat ◽  
Velocity Pressure

Natural convection heat transfer in a rotating, differentially heated enclosure is studied numerically in this paper. The rotating enclosure is filled with water-Ag, water-Cu, water-Al2O3, or water-TiO2nanofluids. The governing equations are in velocity, pressure, and temperature formulation and solved using the staggered grid arrangement together with MAC method. The governing parameters considered are the solid volume fraction,0.0 ≤ ϕ ≤ 0.05, and the rotational speeds,3.5≤ Ω ≤ 17.5 rpm, and the centrifugal force is smaller than the Coriolis force and both forces were kept below the buoyancy force. It is found that the angular locations of the local maximums heat transfer were sensitive to rotational speeds and nanoparticles concentration. The global quantity of heat transfer rate increases about 1.5%, 1.1%, 0.8%, and 0.6% by increasing 1%ϕof the nanoparticles Ag, Cu, Al2O3, and TiO2, respectively, for the considered rotational speeds.

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