Heat transfer of a radial, nanofluid water-graphene oxide hydromagnetic flow between coaxial pipes with a variable radius ratio

2020 ◽  
pp. 095440892094819
Author(s):  
Mohsen Javanmard ◽  
Hossein Salmani ◽  
Mohammad Hasan Taheri ◽  
Nematollah Askari ◽  
Mohammad Ali Kazemi
Keyword(s):  
Heat Transfer ◽  
Graphene Oxide ◽  
Biot Number ◽  
Magnetic Parameter ◽  
Volume Fraction ◽  
Radius Ratio ◽  
Bulk Temperature ◽  
Rate Variation ◽  
Nanoparticle Volume Fraction ◽  
Contrary Effect

The main objective of the present study is to analyze the heat transfer of a water-graphene oxide nanofluid flow between coaxial pipes, analytically. The radius ratio of pipes is variable, and a radial constant magnetic field applies to the pipes. Moreover, the Robin boundary condition is considered on the pipe’s walls. As a novelty, the exact solution is utilized to obtain the velocity distribution; further, the energy equation is solved employing the semi-analytical collocation method. The results reveal that the enhancement of nanoparticle volume fraction and radius ratio increases the dimensionless shear stress on pipes walls by 2% and 100%, respectively; consequently, the friction on walls grows. Though, the magnetic parameter has the contrary effect. Furthermore, it is observed the Eckert number augmentation decuples the bulk temperature and the heat transfer. Moreover, when the outer pipe Biot number and radius ratio increase, the bulk temperature and the heat transfer augment more than 90%. However, the magnetic parameter and nanoparticle volume fraction have a contrary effect. Also, as the inner pipe Biot number rises, we do not observe a constant pattern for the dimensionless temperature and heat transfer rate variation.

scholarly journals Assisted convective heat transfer and entropy generation in a solar collector filled with nanofluid

2016 ◽  
Vol 13 (2) ◽  
pp. 135-150
Author(s):  
R. Nasrin ◽  
M.A. Alim ◽  
M. Hasanuzzzaman
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Entropy Generation ◽  
Solar Collector ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Bulk Temperature ◽  
Outlet Temperature ◽  
Nanoparticle Volume Fraction ◽  
Collector Efficiency

Heat transfer phenomena of flat plate solar collector filled with different nanofluids has been investigated numerically. Galerkin’s Finite Element Method is used to solve the problem. Heat transfer rate, average bulk temperature, average sub-domain velocity, outlet temperature, thermal efficiency, mean entropy generation and Bejan number has been investigated by varying the solid nanoparticle volume fraction of water/Cu, water/Ag and water/Cu/Ag nanofluids from 0% to 3%. It is found that the solid nanoparticle volume fraction has great effect on heat transfer phenomena. It is observed that the increases of the solid volume fraction (up to 2%) enhances the heat transfer rate and collector efficiency where after 2% the rate of change almost constant. Higher heat transfer rate and collector efficiency has been obtained 19% and 13% for water/Ag nanofluid respectively.

scholarly journals Numerical Study of Natural Convection Heat Transfer in a Porous Annulus Filled with a Cu-Nanofluid

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 990
Author(s):  
Lingyun Zhang ◽  
Yupeng Hu ◽  
Minghai Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Darcy Number ◽  
Radius Ratio ◽  
Natural Convection Heat Transfer ◽  
Nanoparticle Volume Fraction ◽  
Convection Heat

Natural convection heat transfer in a porous annulus filled with a Cu nanofluid has been investigated numerically. The Darcy–Brinkman and the energy transport equations are employed to describe the nanofluid motion and the heat transfer in the porous medium. Numerical results including the isotherms, streamlines, and heat transfer rate are obtained under the following parameters: Brownian motion, Rayleigh number (103–105), Darcy number (10−4–10−2), nanoparticle volume fraction (0.01–0.09), nanoparticle diameter (10–90 nm), porosity (0.1–0.9), and radius ratio (1.1–10). Results show that Brownian motion should be considered. The nanoparticle volume fraction has a positive effect on the heat transfer rate, especially with high Rayleigh number and Darcy number, while the nanoparticle diameter has an inverse influence. The heat transfer rate is enhanced with the increase of porosity. The radius ratio has a significant influence on the isotherms, streamlines, and heat transfer rate, and the rate is greatly enhanced with the increase of radius ratio.

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.

Investigation of micropolar hybrid ferrofluid flow over a vertical plate by considering various base fluid and nanoparticle shape factor

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kh. Hosseinzadeh ◽  
So Roghani ◽  
A. Asadi ◽  
Amirreza Mogharrebi ◽  
D.D. Ganji
Keyword(s):  
Magnetic Field ◽  
Shape Factor ◽  
Vertical Plate ◽  
Magnetic Parameter ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Nanoparticle Volume Fraction ◽  
Convection Heat ◽  
Content Type

Purpose The purpose of this paper is to investigate micropolar magnetohydrodynamics (MHD) fluid flow passing over a vertical plate. Three different base fluids have been used that include water, ethylene glycol and ethylene glycol/water (50%–50%). Also, a nanoparticle was used in all of the base fluids. The effects of natural convection heat transfer and magnetic field have been taken into account. Design/methodology/approach The main purpose of solving the governing equations is to scrutinize the effects of the magnetic parameter, the nanoparticle volume fraction, micropolar parameter and nanoparticles shape factor on velocity, temperature and microrotation profiles, the skin friction coefficient and the Nusselt number. These surveys have been considered for three base fluids simultaneously. Findings The results indicate that for water-based fluids, the temperature profile of lamina-shaped nanoparticles is 38.09% higher than brick-shaped nanoparticles. Originality/value This paper provides micropolar MHD fluid flow analysis considering natural convection heat transfer and magnetic field in three different base fluids. The aim of assessments is the diagnosis of some parameter effects, such as magnetic parameter and nanoparticle volume fraction, on velocity, temperature and microrotation profiles and components. Also, the use of mixed base fluids presented as a novelty in this paper.

MHD nanofluid heat transfer between a stretching sheet and a porous surface using neural network approach

2019 ◽  
Vol 30 (06) ◽  
pp. 1950048 ◽  
Author(s):  
Yuancheng Geng ◽  
A. Hassanvand ◽  
Mostafa Monfared ◽  
Rasoul Moradi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Magnetic Parameter ◽  
Volume Fraction ◽  
Sensitivity Analyses ◽  
Integration Scheme ◽  
Group Method ◽  
Suction Parameter ◽  
Wall Injection

Magnetohydrodynamic flow of nanofluids and heat transfer between two horizontal plates in a rotating system have been examined numerically. In order to do this, the group method of data handling (GMDH)-type neural networks is used to calculate Nusselt number formulation. Results indicate that GMDH-type NN in comparison with fourth-order Runge–Kutta integration scheme provides an effective means of efficiently recognizing the patterns in data and accurately predicting a performance. Single-phase model is used in this study. Similar solution is used in order to obtain ordinary differential equation. The effects of nanoparticle volume fraction, magnetic parameter, wall injection/suction parameter and Reynolds number on Nusselt number are studied by sensitivity analyses. The results show that Nusselt number is an increasing function of Reynolds number and volume fraction of nanoparticles but it is a decreasing function of magnetic parameter. Also, it can be found that wall injection/suction parameter has no significant effect on rate of heat transfer.

scholarly journals Flow and Heat Transfer of Cu-Water Nanofluid between a Stretching Sheet and a Porous Surface in a Rotating System

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
M. Sheikholeslami ◽  
H. R. Ashorynejad ◽  
G. Domairry ◽  
I. Hashim
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Base Fluid ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Rotation Parameter ◽  
Nanoparticle Volume Fraction ◽  
Heat Transfer Characteristics ◽  
Rotating System ◽  
Flow And Heat Transfer

The aim of the present paper is to study the flow of nanofluid and heat transfer characteristics between two horizontal plates in a rotating system. The lower plate is a stretching sheet and the upper one is a solid porous plate. Copper (Cu) as nanoparticle and water as its base fluid have been considered. The governing partial differential equations with the corresponding boundary conditions are reduced to a set of ordinary differential equations with the appropriate boundary conditions using similarity transformation, which is then solved analytically using the homotopy analysis method (HAM). Comparison between HAM and numerical solutions results showed an excellent agreement. The results for the flow and heat transfer characteristics are obtained for various values of the nanoparticle volume fraction, suction/injection parameter, rotation parameter, and Reynolds number. It is shown that the inclusion of a nanoparticle into the base fluid of this problem is capable of causing change in the flow pattern. It is found that for both suction and injection, the heat transfer rate at the surface increases with increasing the nanoparticle volume fraction, Reynolds number, and injection/suction parameter and it decreases with power of rotation parameter.

scholarly journals Heat transfer studies of Al2O3/water-ethylene glycol nanofluid using factorial design analysis

2021 ◽  
pp. 21-21
Author(s):  
Srinivasan Manikandan ◽  
Nesakumar Dharmakkan ◽  
Nagamani Sumana
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Ethylene Glycol ◽  
Transfer Coefficient ◽  
Heat Input ◽  
Base Fluid ◽  
Volume Fraction ◽  
Nanoparticle Volume Fraction ◽  
Experimental Heat ◽  
Fluid Concentration

The experimental study of heat transfer coefficient of nanofluid plays a significant role in improving the heat transfer rate of the heat exchanger. The research was conducted in a natural convection heat transfer apparatus by suspending Al2O3 nanoparticle in a base fluid of Water-Ethylene glycol mixture. The effects of heat input (A), nanoparticle volume fraction (B), and base fluid concentration (C) on experimental heat transfer coefficient (hexpnf) were studied. By the results obtained by MINITDesign software 23 full factorial design matrix, 16 experimental runs were performed with the lower and higher level of input factors. The levels for heat input are 10 and 100 W; nanoparticle volume fraction is 0.1 and 1 volume% and for base fluid concentration is 30 and 50 volume% of Ethylene Glycol in water. From the obtained experimental results residual plots, Pareto chart, contour plot and 3D surface plots were drawn. It can be found from the study that the experimental heat transfer coefficient showed highest enhancement with high level of nanoparticle volume fraction and moderate enhancement with high level of heat input and slight enhancement with base fluid concentration.

scholarly journals Homann Stagnation Point Flow and Heat Transfer of Hybrid Nanofluids Over a Permeable Radially Stretching/Shrinking Sheet

2021 ◽  
Vol 85 (1) ◽  
pp. 101-112
Author(s):  
Yap Bing Kho ◽  
Rahimah Jusoh ◽  
Mohd Zuki Salleh ◽  
Mohd Hisyam Ariff ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Stagnation Point ◽  
Volume Fraction ◽  
Stagnation Point Flow ◽  
Shrinking Sheet ◽  
Nanoparticle Volume Fraction ◽  
Flow And Heat Transfer ◽  
Hybrid Nanofluids ◽  
Water Base

The steady two-dimensional Homan stagnation point flow and heat transfer of water base hybrid nanofluids (Al2O3 & Cu) over a permeable radially stretching/shrinking sheet have been studied. The similarity variables are introduced to transform the partial differential equations of the model into the ordinary differential equations. Numerical findings and dual solutions have been carried out by implementing the bvp4c code through MATLAB software. The most prominent effect is illustrated in the boundary layer thickness where the velocity profile increases upon the increment of the suction intensity but decreases in the temperature profile. Besides, the reduced Nusselt number also decreases as enlarging the value of copper and alumina nanoparticle volume fraction. The analysis of the first and second solutions are presented graphically with critical values as well as the detail discussions on the effects of the other involving parameters.

scholarly journals Flow and heat transfer of MHD graphene oxide-water nanofluid between two non-parallel walls

2017 ◽  
Vol 21 (5) ◽  
pp. 2095-2104 ◽  
Author(s):  
Mohammadreza Azimi ◽  
Rouzbeh Riazi
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Graphene Oxide ◽  
Volume Fraction ◽  
Flow And Heat Transfer ◽  
S Parameter ◽  
Non Linear ◽  
Optimal Homotopy Asymptotic Method ◽  
Prandtl Numbers ◽  
Linear Differential

The steady 2-D heat transfer and flow between two non-parallel walls of a graphene oxide nanofluid in presence of uniform magnetic field are investigated in this paper. The analytical solution of the non-linear problem is obtained by Galerkin optimal homotopy asymptotic method. At first a similarity transformation is used to reduce the partial differential equations modeling the flow and heat transfer to ordinary non-linear differential equation systems containing the semi angle between the plate?s parameter, Reynolds number, the magnetic field strength, nanoparticle volume fraction, Eckert and Prandtl numbers. Finally, the obtained analytical results have been compared with results achieved from previous works in some cases.

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