scholarly journals UNSTEADY LAMINAR CONVECTION FLOW OVER PERIODIC GROOVES BY USING SIO2-WATER NANOFLUID

2013 ◽  
pp. 159-165
Author(s):  
AMIRHOSSEIN HESHMATI ◽  
MOHAMMAD PARSAZADEH ◽  
FARSHID FATHINIA
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Convection Flow ◽  
Channel Height ◽  
Uniform Heat Flux ◽  
Nanoparticles Volume Fraction ◽  
Laminar Convection ◽  
Volume Method ◽  
Laminar Forced Convection ◽  
Upwind Method

Unsteady laminar forced convection flow in a 2-dimensional channel over periodic grooves is numerically investigated. Finite volume method is used and the equations were discretized by second order upwind method. The ribheight to channel-height ratio (B/H) is 2. The downstream wall is heated by a uniform heat flux while the upstream wall is insulated. Quasi steady point was obtained at τ=10. The heat transfer is analyzed with different nanoparticles volume fraction and diameter of 0-4% and 20nm-50nm for SiO2 respectively at Reynolds number of 400 and τ=10. Water is used as a base fluid of nanoparticles. The results revealed 124% heat transfer enhancement compared to the water in a grooved channel by using SiO2 nanoparticle with volume fraction and nanoparticle diameter of 4% and 20nm respectively.

scholarly journals Lid-Driven and Inclined Square Cavity Filled With a Nanofluid: Optimum Heat Transfer

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Abdelkader Boutra ◽  
Karim Ragui ◽  
Nabila Labsi ◽  
Youb Khaled Benkahla
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Numerical Study ◽  
Square Enclosure ◽  
Coupled Equations ◽  
Flow And Heat Transfer ◽  
Wide Range ◽  
Optimum Heat ◽  
Nanoparticles Volume Fraction ◽  
Volume Method

AbstractThis paper reports a numerical study on mixed convection within a square enclosure, filled with a mixture of water and Cu (or Ag) nanoparticles. It is assumed that the temperature difference driving the convection comes from the side moving walls, when both horizontal walls are kept insulated. In order to solve the general coupled equations, a code based on the finite volume method is used and it has been validated after comparison between the present results and those of the literature. To make clear the effect of the main parameters on fluid flow and heat transfer inside the enclosure, a wide range of the Richardson number, taken from 0.01 to 100, the nanoparticles volume fraction (0% to 10%), and the cavity inclination angle (0º to 180º) are investigated. The phenomenon is analyzed through streamlines and isotherm plots, with special attention to the Nusselt number.

Heat Transfer Enhancement of Water Based Al2O3- Cu Hybrid Nanofluid Trough Square Cavity

2021 ◽  
Vol 1167 ◽  
pp. 87-100
Author(s):  
Amira Trodi ◽  
Mohamed El Hocine Benhamza
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Volume Fraction ◽  
General Structure ◽  
Hybrid Nanofluid ◽  
Transfer Enhancement ◽  
Numerical Work ◽  
Thermal Fields ◽  
Nanoparticles Volume Fraction ◽  
Volume Method

The present numerical work, based on the finite volume method, deals with the characterization of natural convective flow and thermal fields inside differentially vertical heated square cavities filled with a nanofluid as well as the quantification of the convective exchanges. The investigation is devoted to study the influence of the hybrid nanofluid (Al2O3-Cu / water) on the flow’s general structure with a particular attention to the Nusselt number. An exhaustive parametric study is conducted considering different combinations of Al2O3 and Cu nanoparticles (NPs) dispersed in water for a range of Rayleigh numbers (Ra) and total volume fractions An appropriate agreement with experimental data was observed for the estimation of the hybrid nanofluid thermal conductivity. From the results, it is observed that the heat transfer intensifies by increasing the Ra number and the nanoparticles volume fraction. The hybrid nanofluid seems to be the most efficient nanofluid in comparison with a base fluid and a single nanofluid. This heat transfer enhancement becomes more convincing with the increase of the Cu NPs content (% in volume).

scholarly journals Numerical investigation of nanofluid turbulent flow in a wavy channel with different wavelengths, amplitudes & phase lag

2017 ◽  
Vol 37 (1) ◽  
pp. 99-111 ◽  
Author(s):  
Toran Tavangar ◽  
Abbas Ramiar ◽  
Amir Arya ◽  
Reza Mohammadyari ◽  
Mazaher Rahimi-Esbo
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Phase Lag ◽  
Wavy Channel ◽  
Collocated Grid ◽  
Nanoparticles Volume Fraction ◽  
Volume Method ◽  
Good Agreement

Two dimensional incompressible turbulent nanofluid flow in a sinusoidal wavy channel is numerically investigated. Finite volume method and Rhie and Chow interpolation in a collocated grid arrangement are used for solving governing equations. The effects of the volume fraction of nanoparticles, Reynolds number, phase lag, frequency and amplitude of the wavy walls on the heat transfer rate are studied. The present work showed good agreement with existing experimental and numerical results. Increasing the frequency and amplitude of the wave and nanoparticles volume fraction has great effect on heat transfer rate.

Numerical Investigation of Forced Convection of Nanofluids in Circular Tubes

2007 ◽  
Author(s):  
Fabio Chiacchio ◽  
Oronzio Manca ◽  
Sergio Nardini
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Convective Heat Transfer Coefficient ◽  
Convection Flow ◽  
Uniform Heat Flux ◽  
Particle Volume ◽  
Two Phase ◽  
Liquid Heat ◽  
Temperature Dependent Properties ◽  
Laminar Forced Convection

In this paper developing laminar forced convection flow of a water–γAl2O3 nanofluid in a circular tube submitted to a constant and uniform heat flux at the wall is numerically investigated. A single and two-phase model (discrete particles model) is employed with either constant or temperature-dependent properties. The investigation is accomplished for a size particles equal to 100 nm. Convective heat transfer coefficient for nanofluids is greater than that of the base liquid. Heat transfer enhancement is increasing with the particle volume concentration but it is accompanied by increasing wall shear stress values. The effect of Reynolds number is greater when properties depend on temperature and for higher concentrations.

Effect of Nanofluid on Heat Transfer Enhancement for Mixed Convection Flow Over a Corrugated Surface

2020 ◽  
Vol 45 (4) ◽  
pp. 373-383
Author(s):  
Nepal Chandra Roy ◽  
Sadia Siddiqa
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Local Nusselt Number ◽  
Richardson Number ◽  
Thermal Boundary Layer ◽  
Volume Fraction ◽  
Convection Flow ◽  
Mixed Convection Flow

AbstractA mathematical model for mixed convection flow of a nanofluid along a vertical wavy surface has been studied. Numerical results reveal the effects of the volume fraction of nanoparticles, the axial distribution, the Richardson number, and the amplitude/wavelength ratio on the heat transfer of Al2O3-water nanofluid. By increasing the volume fraction of nanoparticles, the local Nusselt number and the thermal boundary layer increases significantly. In case of \mathrm{Ri}=1.0, the inclusion of 2 % and 5 % nanoparticles in the pure fluid augments the local Nusselt number, measured at the axial position 6.0, by 6.6 % and 16.3 % for a flat plate and by 5.9 % and 14.5 %, and 5.4 % and 13.3 % for the wavy surfaces with an amplitude/wavelength ratio of 0.1 and 0.2, respectively. However, when the Richardson number is increased, the local Nusselt number is found to increase but the thermal boundary layer decreases. For small values of the amplitude/wavelength ratio, the two harmonics pattern of the energy field cannot be detected by the local Nusselt number curve, however the isotherms clearly demonstrate this characteristic. The pressure leads to the first harmonic, and the buoyancy, diffusion, and inertia forces produce the second harmonic.

scholarly journals The Influence of Different Types of Nanofluid on Thermal and Fluid Flow Performance of Liquid Cold Plate

2018 ◽  
Vol 7 (4.35) ◽  
pp. 148 ◽  
Author(s):  
Nur Irmawati Om ◽  
Rozli Zulkifli ◽  
P. Gunnasegaran
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Steady State ◽  
Pressure Drop ◽  
Volume Fraction ◽  
Cold Plate ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Different Types ◽  
Volume Method

The influence of utilizing different nanofluids types on the liquid cold plate (LCP) is numerically investigated. The thermal and fluid flow performance of LCP is examined by using pure ethylene glycol (EG), Al2O3-EG and CuO-EG. The volume fraction of the nanoparticle for both nanofluid is 2%. The finite volume method (FVM) has been used to solved 3-D steady state, laminar flow and heat transfer governing equations. The presented results indicate that Al2O3-EG able to provide the lowest surface temperature of the heater block followed by CuO-EG and EG, respectively. It is also found that the pressure drop and friction factor are higher for Al2O3-EG and CuO-EG compared to the pure EG.

Entropy generation optimization for MHD natural convection of a nanofluid in porous media-filled enclosure with active parts and viscous dissipation

2017 ◽  
Vol 27 (2) ◽  
pp. 379-399 ◽  
Author(s):  
M.A. Mansour ◽  
Sameh Elsayed Ahmed ◽  
Ali J. Chamkha
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Convection Flow ◽  
Negative Effects ◽  
Content Type ◽  
Volume Method

Purpose This paper aims to investigate the entropy generation due to magnetohydrodynamic natural convection flow and heat transfer in a porous enclosure filled with Cu-water nanofluid in the presence of viscous dissipation effect. The left and right walls of the cavity are thermally insulated. There are heated and cold parts, and these are placed on the bottom and top wall, respectively, whereas the remaining parts are thermally insulated. Design/methodology/approach The finite volume method is used to solve the dimensionless partial differential equations governing the problem. A comparison with previously published woks is presented and is found to be in an excellent agreement. Findings The minimization of entropy generation and local heat transfer according to different values of the governing parameters are presented in details. It is found that the presence of magnetic field has negative effects on the local entropy generation because of heat transfer and the local total entropy generation. Also, the increase in the heated part length leads to a decrease in the local Nusselt number. Originality/value This problem is original, as it has not been considered previously.

CFD Based Analysis of Laminar Forced Convection of Nanofluid Separated Flow Under the Presence of Magnetic Field

2016 ◽  
Vol 32 (6) ◽  
pp. 777-785
Author(s):  
M. Besanjideh ◽  
M. Hajabdollahi ◽  
S. A. Gandjalikhan Nassab
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Volume Fraction ◽  
Separated Flow ◽  
Fluid Temperature ◽  
Flow And Heat Transfer ◽  
Contraction Ratio ◽  
Nanoparticles Volume Fraction ◽  
Energy Equations ◽  
Laminar Forced Convection

AbstractThis paper deals with studying fluid flow and heat transfer of nanofluid through a forward facing step channel which is affected by a uniform magnetic field transverse to fluid flow. All the channel walls are assumed to be in constant temperature and the fluid temperature at the channel inlet is less than that of the walls. Also, the nanofluid is considered as a single-phase Newtonian fluid and the proper correlations were utilized to determine the thermophysical properties of nanofluid. Therefore, a code has been developed and two-dimensional continuity, momentum and energy equations were solved, using CFD technique. The computations were conducted for different values of the Reynolds and Hartmann numbers, and contraction ratio and an extensive range of nanoparticles volume fraction. The results indicated that flow separation and reattachment phenomena, in vicinity of the step edge, could be influenced strongly by magnetic field and the average Nusselt number is increased significantly by increasing nanoparticles volume fraction and Hartmann number.

Numerical Analysis on Nanofluid Forced Convection in Ducts With Triangular Cross Sections

2011 ◽  
Author(s):  
O. Manca ◽  
S. Nardini ◽  
D. Ricci ◽  
S. Tamburrino
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Forced Convection ◽  
Cross Sections ◽  
Fluid Dynamic ◽  
Pure Water ◽  
Convection Flow ◽  
Uniform Heat Flux ◽  
Surface Shear Stress ◽  
Surface Shear

Heat transfer of fluids is very important to many industrial heating or cooling equipments. Convective heat transfer can be enhanced passively by changing flow geometry, boundary conditions or by enhancing the thermal conductivity of the working fluids. An innovative way of improving the fluid thermal conductivity is to introduce suspended small solid nanoparticles in the base fluids. In this paper a numerical investigation on laminar forced convection flow of a water–Al2O3 nanofluid in a duct having an equilateral triangular cross section is performed. The hydraulic diameter is set equal to 1.0×10−2 m. A constant and uniform heat flux on the external surfaces has been applied and the single-phase model approach has been employed. The analysis has been run in steady state regime for a nanoparticle size equal to 38 nm, considering different volume particle concentrations. The CFD code Fluent has been employed in order to solve the tri-dimensional numerical model. Results are presented in terms of temperature and velocity distributions, surface shear stress and heat transfer convective coefficient, Nusselt number and required pumping power profiles. Comparison with results related to the fluid dynamic and thermal behaviors in pure water are carried out in order to evaluate the enhancement due to the presence of nanoparticles in terms of volumetric concentration.

scholarly journals Study of convection heat transfer enhancement inside lid driven cavity utilizing fins and nanofluid

2017 ◽  
Vol 21 (6 Part A) ◽  
pp. 2431-2442
Author(s):  
Arash Lavasani ◽  
Mousa Farhadi ◽  
Darzi Rabienataj
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Richardson Number ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Thermal Conductivity Ratio ◽  
Convection Flow ◽  
Driven Cavity ◽  
Ratio Change ◽  
Hot Surface

In the present study, the effect of suspension of nanoparticle on mixed convection flow is investigated numerically in lid driven cavity with fins on its hot surface. Study is carried out for Richardson numbers ranging from 0.1 to 10, fin(s) height ratio change from 0.05 to 0.15 and volume fraction of nanoparticles from 0 to 0.03, respectively. The thermal conductivity ratio (kfin/kf) is equal to 330 and Grashof number is assumed to be constant (104) so that the Richardson numbers changes with Reynolds number. Results show that the heat transfer enhances by using nanofluid for all studied Richardson numbers. Adding fins on hot wall has different effects on heat transfer depend to Richardson number and height of fins. Use of low height fin in flow with high Richardson number enhances the heat transfer rate while by increasing the height of fin the heat transfer reduces even lower than it for pure fluid. The overall enhancement in Nusselt number by adding 3% nanoparticles and 3 fins is 54% at Ri=10. They cause reduction of Nusselt Number by 25% at Ri=0.1. Higher fins decrease the heat transfer due to blocking fluid at corners of fins.

Sign in / Sign up

Export Citation Format

Share Document