A Note on Double Dispersion Effects in a Nanofluid Flow in a Non-Darcy Porous Medium

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
F. G. Awad ◽  
P. Sibanda ◽  
P. V. S. N. Murthy
Keyword(s):  
Mass Transfer ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Linearization Method ◽  
Physical Parameters ◽  
Nanofluid Flow ◽  
Transfer Characteristics ◽  
Dispersion Effects ◽  
Brownian Motion And Thermophoresis ◽  
Double Dispersion

A non-Darcian model has been employed to investigate a nanofluid flow in a porous layer with double dispersion effects. The model incorporates Brownian motion and thermophoresis to study heat and mass transfer characteristics within the nanofluid. A similarity transformation is used to obtain a system of ordinary differential equations that are solved numerically using a linearization method. The effects of fluid and physical parameters such as thermal and solutal dispersions, the Brownian motion, and thermophoresis on the heat and mass transfer characteristics of the nanofluid are determined, and for some limiting cases, compared to results in the literature.

Unsteady convective heat and mass transfer of a nanofluid in Howarth’s stagnation point by Buongiorno’s model

2015 ◽  
Vol 25 (5) ◽  
pp. 1176-1197 ◽  
Author(s):  
Saeed Dinarvand ◽  
Reza Hosseini ◽  
Ioan Pop
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Three Dimensional ◽  
Stagnation Point Flow ◽  
Content Type ◽  
Buongiorno’S Model ◽  
Brownian Motion And Thermophoresis

Purpose – The purpose of this paper is to do a comprehensive study on the unsteady general three-dimensional stagnation-point flow and heat transfer of a nanofluid by Buongiorno’s model. Design/methodology/approach – In this study, the convective transport equations include the effects of Brownian motion and thermophoresis. By introducing new similarity transformations for velocity, temperature and nanoparticle volume fraction, the basic equations governing the flow, heat and mass transfer are reduced into highly non-linear ordinary differential equations. The resulting non-linear system has been solved both analytically and numerically. Findings – The analysis shows that velocity, temperature and nanoparticle concentration profiles in the respective boundary layers depend on five parameters, namely unsteadiness parameter A, Brownian motion parameter Nb, thermophoresis parameter Nt, Prandtl number Pr and Lewis number Le. It is found that the thermal boundary layer thickens with a rise in both of the Brownian motion and the thermophoresis effects. Therefore, similar to the earlier reported results, the Nusselt number decreases as the Brownian motion and thermophoresis effects become stronger. A correlation for the Nusselt number has been developed based on a regression analysis of the data. This correlation predicts the numerical results with a maximum error of 9 percent for a usual domain of the physical parameters. Originality/value – The stagnation point flow toward a wavy cylinder (with nodal and saddle stagnation points) that a little attention has been given to it up to now. The examination of unsteadiness effect on the general three-dimensional stagnation-point flow. The application of an interesting and global model (Boungiorno’s model) for the nanofluid that incorporates the effects of Brownian motion and thermophoresis. The study of the effects of Brownian motion and thermophoresis on the nanofluid flow, heat and mass transfer characteristics. The prediction of correlation for the Nusselt number based on a regression analysis of the data. General speaking, we can tell the problem with this geometry, characteristics, the applied model, and comprehensive results, was Not studied and analyzed in literature up to now.

Heat and mass transfer in MHD Casson nanofluid flow past a stretching sheet with thermophoresis and Brownian motion

Heat Transfer ◽  
2020 ◽  
Vol 49 (8) ◽  
pp. 5020-5037
Author(s):  
Ankalagiri Chinna Venkata Ramudu ◽  
Kempannagari Anantha Kumar ◽  
Vangala Sugunamma ◽  
Naramgari Sandeep
Keyword(s):  
Mass Transfer ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Stretching Sheet ◽  
Nanofluid Flow ◽  
Casson Nanofluid ◽  
And Brownian Motion ◽  
Flow Past

Heat and mass transfer analysis in natural convection flow of nanofluid over a vertical cone with chemical reaction

2017 ◽  
Vol 27 (1) ◽  
pp. 2-22 ◽  
Author(s):  
P. Sudarsana Reddy ◽  
A. Chamkha
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Concentration Profiles ◽  
Vertical Cone ◽  
Content Type ◽  
Boundary Layer Region ◽  
Brownian Motion And Thermophoresis ◽  
Layer Region

Purpose In recent years, nanofluids are being widely used in many thermal systems because of their higher thermal conductivity and heat transfer rate. The higher thermal conductivity depends on many parameters such as size, shape and volume and the Brownian motion and thermophoresis of added nanoparticles. The purpose of this paper is to analyze the influence of the Brownian motion and thermophoresis on natural convection heat and mass transfer boundary layer flow of nanofluids over a vertical cone with radiation. Design/methodology/approach Using similarity variables, the non-linear partial differential equations, which represent momentum, energy and diffusion, are transformed into ordinary differential equations. The transformed conservation equations are solved numerically subject to the boundary conditions by using versatile, extensively validated, variational finite-element method. Findings The sway of significant parameters such as magnetic field (M), buoyancy ratio parameter (Nr), Brownian motion parameter (Nb), thermophoresis parameter (Nt), thermal radiation (R), Lewis number (Le) and chemical reaction parameter (Cr) on velocity, temperature and concentration evaluation in the boundary layer region is examined in detail. The results are compared with previously published work and are found to be in agreement. The velocity distributions are reduced, while temperature and concentration profiles elevate with a higher (M). With the improving values of (R), the velocity and temperature sketches improve, while concentration distributions are lowered in the boundary layer region. The temperature and concentration profiles are elevated in the boundary layer region for higher values of (Nt). With the increasing values of (Nb), temperature profiles are enhanced, whereas concentration profiles get depreciated in the flow region. Social implications In recent years, it has been found that magneto-nanofluids are significant in many areas of science and technology. It has applications in optical modulators, magnetooptical wavelength filters, tunable optical fiber filters and optical switches. Magnetic nanoparticles are especially useful in biomedicine, sink float separation, cancer therapy, etc. Specific biomedical applications involving nanofluids include hyperthermia, magnetic cell separation, drug delivery and contrast enhancement in magnetic resonance imaging. Originality/value To the best of the authors’ knowledge, no studies have assessed the impact of the two slip effects, namely, Brownian motion and thermophoresis, on the natural convection of electrically conducted heat and mass transfer to the nanofluid boundary layer flow over a vertical cone in the presence of radiation and chemical reaction; therefore, this problem has been addressed in this study. Comparison of the results of this study’s with those of previously published work was found to be in good agreement.

Second Law Analysis of Heat and Mass Transfer of Nanofluids Along a Plate With Prescribed Surface Heat Flux

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Waqar A. Khan ◽  
Richard Culham ◽  
A. Aziz
Keyword(s):  
Mass Transfer ◽  
Brownian Motion ◽  
Differential Equations ◽  
Heat And Mass Transfer ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Entropy Generation Rate ◽  
Second Law ◽  
Second Law Analysis ◽  
Brownian Motion And Thermophoresis

A model based on the works of Buongiorno, which includes the effects of Brownian motion and thermophoresis, is used to develop the governing equations for convection in nanofluids. The analysis includes examples with water and ethylene glycol as the base fluids and nanoparticles of Cu and Al2O3. An assumption of zero nanoparticle flux is used at the surface of the plate to make the model more physically realistic. The model accounts for the effects of both Brownian motion and thermophoresis in the mass boundary condition. Using suitable transformations, the governing partial differential equations are converted into ordinary differential equations which are solved numerically. The dimensionless velocity, temperature, and concentration gradients are used in the second law analysis to determine heat and mass transfer rates. It is shown that the dimensionless entropy generation rate strongly depends upon the solid volume fraction of the nanoparticles, local Reynolds number, and group parameters.

Effects of Hall Current and Chemical Reaction on Magnetohydrodynamics Unsteady Heat and Mass Transfer of Casson Nanofluid Flow Through a Vertical Plate

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Rajib Biswas ◽  
Sarder Firoz Ahmmed
Keyword(s):  
Mass Transfer ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Chemical Reaction ◽  
Vertical Plate ◽  
Hall Current ◽  
Nanofluid Flow ◽  
Casson Nanofluid ◽  
Flow Through ◽  
Model Equations

In this paper, we have reported the effects of Hall current on magnetohydrodynamics (MHD) unsteady heat and mass transfer of Casson nanofluid flow through a vertical plate in the presence of radiation and chemical reaction. The model equations have been used for the Casson nanofluid and they include the effects of thermophoresis and Brownian motion. Then, the obtained model equations have been transformed into nondimensional form by the usual mathematical procedure of transformation and the resultant nondimensional couple of partial differential equations are solved by explicit finite difference technique. Then, the obtained results are plotted after stability test by using the graphical software tecplot-9 and these results indicate the fluid flow, temperature, and concentration distributions which are significantly invaded by the variation of different dimensionless parameters such as magnetic parameter, Schmidt number, thermal Grashof number, Lewis number, Prandtl number, mass Grashof number, Dufour number, thermophoresis parameter, Brownian motion parameter, chemical reaction, and radiation parameter on velocity, temperature, and concentration along with the skin friction coefficient, Nusselt number, and Sherwood number. Further, the results have been discussed also with the help of graphs. Furthermore, it is observed that with the increase of the Casson parameter, velocity puts down, whereas by increasing the heat generation parameter, the temperature profiles are decreased.

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