Go-water nanofluid inside semi porous channel: analytical investigation

2015 ◽  
Vol 12 (2) ◽  
pp. 103-108 ◽  
Author(s):  
M. Azimi ◽  
R. Riazi

This paper concerns the analytical investigation of the GO-water nanofluid flow in a semi-porous channel. The Similarity Berman’s transformation is employed to convert the governing partial differential equations of a steady laminar flow of an electrically conducting fluid in a two dimensional channel. Reconstruction of Variational Iteration Method (RVIM) has been used to obtain the expressions for velocity fields. Graphs are sketched and discussed for various parameters, especially the effect of the expansion ratio on velocity fields. The results indicated that the Reynolds number, Hartmann number and solid volume fraction have strong effect on velocity boundary layer thickness.

Author(s):  
MJ Uddin ◽  
MN Kabir ◽  
O Anwar Bég ◽  
Y Alginahi

In this article, the steady two-dimensional stagnation point flow of a viscous incompressible electrically conducting bio-nanofluid over a stretching/shrinking wedge in the presence of passively control boundary condition, Stefan blowing and multiple slips is numerically investigated. Magnetic induction is also taken into account. The governing conservation equations are rendered into a system of ordinary differential equations via appropriate similarity transformations. The reduced system is solved using a fast, convergent Chebyshev collocation method. The influence of selected parameters on the dimensionless velocity, induced magnetic field, temperature, nanoparticle volume fraction and density of motile microorganisms as well as on the local skin friction, local Nusselt number, local Sherwood number and density of motile microorganism numbers is discussed and presented graphically. Validation with previously published results is performed and an excellent agreement is found. The study is relevant to electromagnetic manufacturing processes involving bio-nanofluids.


2020 ◽  
Vol 307 ◽  
pp. 01010 ◽  
Author(s):  
Ahlem Boudiaf ◽  
Fetta Danane ◽  
Youb Khaled Benkahla ◽  
Walid Berabou ◽  
Mahdi Benzema ◽  
...  

This paper presents the numerical predictions of hydrodynamic and thermal characteristics of nanofluid flow through backward facing step. The governing equations are solved through the finite volume method, as described by Patankar, by taking into account the associated boundary conditions. Empirical relations were used to give the effective dynamic viscosity and the thermal conductivity of the nanofluid. Effects of different key parameters such as Reynolds number, nanoparticle solid volume fraction and nanoparticle solid diameter on the heat transfer and fluid flow are investigated. The results are discussed in terms of the average Nusselt number and streamlines.


2015 ◽  
Vol 08 (04) ◽  
pp. 1550050 ◽  
Author(s):  
Navid Freidoonimehr ◽  
Behnam Rostami ◽  
Mohammad Mehdi Rashidi

In this paper a definitely new analytical technique, predictor homotopy analysis method (PHAM), is employed to solve the problem of two-dimensional nanofluid flow through expanding or contracting gaps with permeable walls. Moreover, comparison of the PHAM results with numerical results obtained by the shooting method coupled with a Runge–Kutta integration method as well as previously published study results demonstrates high accuracy for this technique. The fluid in the channel is water containing different nanoparticles: silver, copper, copper oxide, titanium oxide, and aluminum oxide. The effects of the nanoparticle volume fraction, Reynolds number, wall expansion ratio, and different types of nanoparticles on the flow are discussed.


2013 ◽  
Vol 246 ◽  
pp. 327-336 ◽  
Author(s):  
M. Sheikholeslami ◽  
M. Hatami ◽  
D.D. Ganji

2016 ◽  
Vol 33 (2) ◽  
pp. 213-224 ◽  
Author(s):  
A. Vijayalakshmi ◽  
S. Srinivas

AbstractThe present study investigates the hydromagnetic pulsating nanofluid flow in a porous channel with thermal radiation. In this work, we considered water as the base fluid and silver (Ag), copper (Cu), alumina (Al2O3) and titanium dioxide (TiO2) as nanoparticles. The Maxwell-Garnetts and Brinkman models are used to evaluate the effective thermal conductivity and viscosity of the nanofluid. The governing equations are solved analytically and the influence of various parameters on velocity, temperature and heat transfer rate has been discussed through graphical results. From the results, it is found that the rate of heat transfer enhances with an increase of nanoparticle volume fraction. Further, the heat transfer rate is higher for silver nanoparticles as compared with copper, alumina and titanium dioxide.


2013 ◽  
Vol 61 (2) ◽  
pp. 126-133g ◽  
Author(s):  
Gianandrea Vittorio Messa ◽  
Stefano Malavasi

Abstract The flow of a solid-water mixture through an upward-facing step in a channel is numerically investigated. The effect of expansion ratio, mean solids volume fraction and particle diameter on the velocity field, pressure distribution and solid volume fraction field is studied. Expansion ratios of 0.50 and 0.67, particle diameter of 125 μm and 440 μm and mean solid volume fraction between 0.05 and 0.20 are considered. Particle density is 2465 kg m-3. An Eulerian twofluid model is used to simulate the flow. Due to the lack of experimental data, the model was validated by comparison to other numerical investigations and to experimental data about the horizontal pipe case. Afterwards, it is studied the effect of the above mentioned parameters upon the degree of coupling between the phases and the extension of the disturbance region in the pressure and solid volume fraction fields downstream the step. Parameters of engineering interest, such as the reattachment length and the pressure recovery downstream the enlargement, are investigated.


2021 ◽  
Vol 11 (4) ◽  
pp. 1722
Author(s):  
Nidal Abu-Libdeh ◽  
Fares Redouane ◽  
Abderrahmane Aissa ◽  
Fateh Mebarek-Oudina ◽  
Ahmad Almuhtady ◽  
...  

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.


Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Xinhui Si ◽  
Liancun Zheng ◽  
Xinxin Zhang ◽  
Ying Chao

AbstractThe flow of a micropolar fluid in a porous channel with expanding or contracting walls is investigated. The governing equations are reduced to ordinary ones by using similar transformations. Homotopy analysis method (HAM) is employed to obtain the expressions for the velocity fields and microrotation fields. Graphs are sketched for the effects of some values of parameters, especially the expansion ratio, on the velocity and microrotation fields and associated dynamic characteristics are analyzed in detail.


Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5506
Author(s):  
Dianchen Lu ◽  
Muhammad Idrees Afridi ◽  
Usman Allauddin ◽  
Umer Farooq ◽  
Muhammad Qasim

The present study explores the entropy generation, flow, and heat transfer characteristics of a dissipative nanofluid in the presence of transpiration effects at the boundary. The non-isothermal boundary conditions are taken into consideration to guarantee self-similar solutions. The electrically conducting nanofluid flow is influenced by a magnetic field of constant strength. The ultrafine particles (nanoparticles of Fe3O4/CuO) are dispersed in the technological fluid water (H2O). Both the base fluid and the nanofluid have the same bulk velocity and are assumed to be in thermal equilibrium. Tiwari and Dass’s idea is used for the mathematical modeling of the problem. Furthermore, the ultrafine particles are supposed to be spherical, and Maxwell Garnett’s model is used for the effective thermal conductivity of the nanofluid. Closed-form solutions are derived for boundary layer momentum and energy equations. These solutions are then utilized to access the entropy generation and the irreversibility parameter. The relative importance of different sources of entropy generation in the boundary layer is discussed through various graphs. The effects of space free physical parameters such as mass suction parameter (S), viscous dissipation parameter (Ec), magnetic heating parameter (M), and solid volume fraction (ϕ) of the ultrafine particles on the velocity, Bejan number, temperature, and entropy generation are elaborated through various graphs. It is found that the parabolic wall temperature facilitates similarity transformations so that self-similar equations can be achieved in the presence of viscous dissipation. It is observed that the entropy generation number is an increasing function of the Eckert number and solid volume fraction. The entropy production rate in the Fe3O4−H2O nanofluid is higher than that in the CuO−H2O nanofluid under the same circumstances.


2018 ◽  
Vol 22 (Suppl. 5) ◽  
pp. 1435-1447 ◽  
Author(s):  
Recep Ekiciler ◽  
Emre Aydeniz ◽  
Kamil Arslan

In this paper, flow and heat transfer characteristics of SiO2-water nanofluid flow over a corrugated backward-facing step are numerically investigated. The numerical study is performed by solving governing equations (continuity, momentum, and energy) with finite volume method. The duct inlet and step heights are 4.8 mm. The expansion ratio is 2. The upstream wall, Lu, and downstream wall, Ld, lengths are 48 cm and 96 cm, respectively. The downstream wall of the duct is subjected to a constant and uniform heat flux of 2000 W/m2. The ranges of the volume fraction of nanoparticles and Reynolds number are 0%-3.0% and 135-240, respectively. The effects of the volume fraction of nanoparticles on the average Nusselt number, average Darcy friction factor, and velocity distribution are investigated under laminar forced convective nanofluid flow condition. It is revealed that the nanoparticle volume fraction substantially influences the heat transfer and flow characteristics. The volume fraction of 3.0% shows the highest heat transfer performance.


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