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1
Content available Flow features of thermophoretic MHD viscous fluid flow past a converging channel with heat source and chemical reaction
Kalita B. K., Choudhury R.
International Journal of Applied Mechanics and Engineering
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2021
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Vol. 26, no. 3
72--83
EN
A boundary layer flow of an electrically conducting viscous fluid past a converging channel in the presence of thermophoresis, heat source, chemical reaction, viscous dissipation and simultaneous heat and mass transfer characteristics is studied in the paper. An external magnetic field of uniform strength is applied transversely to the channel. The similarity solution has been used to transform the partial differential equations that represent the problem into a boundary value problem of coupled ordinary differential equations, which in turn are solved numerically using MATLAB’s built in solver bvp4c. Numerical computations are carried out to solve the problem and graphical illustrations are made to get the physical insight of the same. The convergent channel flow problem of an incompressible electrically conducting viscous fluid in the presence of a magnetic field has a wide range of applicability in different areas of engineering, specially in industrial metal casting and control of molten metal flow.
2
Content available remote A revised model for the effect of nanoparticle mass flux on the thermal instability of a nanofluid layer
Alharbi Ozwah S., Abdullah Abdullah A.
Demonstratio Mathematica
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2021
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Vol. 54, nr 1
488--499
EN
A revised model of the nanoparticle mass flux is introduced and used to study the thermal instability of the Rayleigh-Benard problem for a horizontal layer of nanofluid heated from below. The motion of nanoparticles is characterized by the effects of thermophoresis and Brownian diffusion. The nanofluid layer is confined between two rigid boundaries. Both boundaries are assumed to be impenetrable to nanoparticles with their distribution being determined from a conservation condition. The material properties of the nanofluid are allowed to depend on the local volume fraction of nanoparticles and are modelled by non-constant constitutive expressions developed by Kanafer and Vafai based on experimental data. The results show that the profile of the nanoparticle volume fraction is of exponential type in the steady-state solution. The resulting equations of the problem constitute an eigenvalue problem which is solved using the Chebyshev tau method. The critical values of the thermal Rayleigh number are calculated for several values of the parameters of the problem. Moreover, the critical eigenvalues obtained were real-valued, which indicates that the mode of instability is via a stationary mode.
3
Content available Heat and mass transfer flow of nanofluids in presence of chemical reaction with partial slip conditions
Narender G., Govardhan K., Sreedhar-Sarma G.
Journal of Applied Mathematics and Computational Mechanics
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2020
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Vol. 19, nr 3
71-84
EN
A mathematical model is presented for analyzing the convective fluid over a stretching surface in the presence of nanoparticles. The analysis of heat and mass transfer of converted fluid with slip boundary condition is investigated. To convert the governing Partial Differential Equations (PDEs) into a system of nonlinear Ordinary Differential Equations (ODEs) we use similarity transformations. The shooting method is used to solve the system of ODEs numerically, and obtained numerical results are compared with the published results and found that both are in excellent agreement. The numerical values obtained for the velocity, temperature and concentration profiles are presented through graphs and tables. A discussion on the effects of various physical parameters and heat transfer characteristics is also included.
4
Content available Mathematical modeling of convective heat and mass transfer of a rotating nano-fluid bounded by stretching and stationary walls in a vertical conduit
Haritha B., Umadevi C., Dhange M. Y.
International Journal of Applied Mechanics and Engineering
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2020
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Vol. 25, no. 4
69--83
EN
The influence of thermal emission and unvarying magnetic field of convective heat and mass transfer of a rotating nano-liquid in an upright conduit constrained by a stretching and motionless wall is studied. The temperature, concentration profile, primary and secondary velocities have been computed through similarity transformation and fourth-order Runge-Kutta shooting technique. The objective of this article is to measure the impact of emission constraint, Brownian movement constraint and Eckert number, thermophoresis constraint, Prandtl number, space, and temperature-dependent heat source constraint on velocity. The results are presented in tables and graphs. Further, various constraint impacts on the skin friction coefficient, heat and mass transfer rates are also explored. This work is pertinent to biotechnological and engineering uses, like mass and heat transfer enhancement of microfluids and design of bioconjugates.
5
Content available Influence of chemical reaction on the heat and mass transfer of nanofluid flow over a nonlinear stretching sheet: a numerical study
Misra Santoshi, Govardhan K.
International Journal of Applied Mechanics and Engineering
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2020
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Vol. 25, no. 2
103--121
EN
A numerical study on a steady, laminar, boundary layer flow of a nanofluid with the influence of chemical reaction resulting in the heat and mass transfer variation is made. The non-linear governing equations with related boundary conditions are solved using Adam’s predictor corrector method with the effect of a Brownian motion and thermophoresis being incorporated as a model for the nanofluid, using similarity transformations. Validation of the current numerical results has been made in comparison to the existing results in the absence of chemical reaction on MHD flows. The numerical solutions obtained for the velocity, temperature and concentration profiles for the choice of various parameters are represented graphically. Variations of heat and mass transfer across a Brownian motion and thermophoresis are studied and analyzed.
6
Content available Melting heat transfer and MHD boundary layer flow of Eyring-Powell nanofluid over a nonlinear stretching sheet with slip
Reddy N. V. B., Kishan N., Reddy C. S.
International Journal of Applied Mechanics and Engineering
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2019
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Vol. 24, no. 1
161--178
EN
The steady laminar incompressible viscous magneto hydrodynamic boundary layer flow of an Eyring- Powell fluid over a nonlinear stretching flat surface in a nanofluid with slip condition and heat transfer through melting effect has been investigated numerically. The resulting nonlinear governing partial differential equations with associated boundary conditions of the problem have been formulated and transformed into a non-similar form. The resultant equations are then solved numerically using the Runge-Kutta fourth order method along with the shooting technique. The physical significance of different parameters on the velocity, temperature and nanoparticle volume fraction profiles is discussed through graphical illustrations. The impact of physical parameters on the local skin friction coefficient and rate of heat transfer is shown in tabulated form.
7
Content available Effect of viscous dissipation and thermoporesis on the flow over an exponentially stretching sheet
Srinivasacharya D., Jagadeeshwar P.
International Journal of Applied Mechanics and Engineering
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2019
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Vol. 24, no. 2
425--438
EN
This article analyses the influence of viscous dissipation and thermoporesis effects on the viscous fluid flow over a porous sheet stretching exponentially by applying convective boundary condition. The numerical solutions to the governing equations are evaluated using a local similarity and non-similarity approach along with a successive linearisation procedure and Chebyshev collocation method. The influence of the pertinent parameters on the physical quantities are displayed through graphs.
8
Content available remote Impact of thermophoretic transport of Al2O3 nanoparticles on viscoelastic flow of oil-based nanofluid over a porous exponentially stretching surface with activation energy
Etwire Christian John, Seini Ibrahim Yakubu, Musah Rabiu, Makinde Oluwole Daniel
Engineering Transactions
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2019
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Vol. 67, iss. 3
387--410
EN
The influence of thermophoretic transport of Al2O3 nanoparticles on heat and mass transfer in viscoelastic flow of oil-based nanofluid past porous exponentially stretching surface with activation energy has been examined. Similarity technique was employed to transform the governing partial differential equations into a coupled fourth-order ordinary differential equations which were reduced to a system of first-order ordinary differential equations and then solved numerically using the fourth-order Runge-Kutta algorithm with a shooting method. The results for various controlling parameters were tabulated and graphically illustrated. It was found that the thermophoretic transport of Al2O3 nanoparticles did not affect the rate of flow and heat transfer at the surface but it affected the rate of mass transfer of the nanofluid which decayed the solutal boundary layer thickness. This study also revealed that activation energy retards the rate of mass transfer which causes a thickening of the solutal boundary layer.
9
Content available Nano-particles transport in a concentric annulus: a lattice Boltzmann approach
Pourmirzaagha H., Hassanzadeh A. H., Abouei M. A.
Journal of Theoretical and Applied Mechanics
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2015
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Vol. 53 nr 3
683--695
EN
A combination of the lattice Boltzmann method and lagrangian Runge-Kutta procedure is used to study dispersion and removal of nano-particles in a concentric annulus. The effect of aspect ratio, Rayleigh number and particles diameter are examined on particles removal and their dispersion characteristics. Simulations are performed for the Rayleigh number ranges from 103 to 105 and aspect ratio of 2, 3 and 4. Higher aspect ratios have led to weaker recirculation strength. The finest particles move on stochastic path due to the effect of Brownian motion. The Brownian motion has a greater effect on the removal of nano-particles with respect to thermophoresis.
10
Content available remote Combined heat and mass transfer on non-Darcy natural convection in a fluid saturated porous medium with thermophoresis
El-Hakiem M. A., El-Kabeir S. M., Rashad A. M.
International Journal of Applied Mechanics and Engineering
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2007
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Vol. 12, no 1
9-18
EN
The present investigation deals with the combined heat and mass transfer with the effects of thermal dispersion, radiation on non-Darcy natural convection in a fluid saturated porous medium with thermophoresis. The goveming equations, reduced to local similarity boundary layer equations using suitable transformations are obtained. Forchheimer extension is considered in the fIow equations. The coefficient of thermal diffusivity has been assumed to be the sum of molecular diffusivity and the dispersion thermal diffusivity due to mechanical dispersion. Rosseland approximation is used to describe the radiative heat fIux in the energy equation. For the fluids having the Lewis number Le=l.O, 10.0, numerical values of the local Stanton number are presented in a tabular form for different values of the thermophoretic parameter [...], thermal dispersion and thermal radiation for the two cases of Darcy and non-Darcy porous medium. The concentration distributions are show n graphically for various values of the thermophoretic parameter, thermal dispersion and thermal radiation.
11
Dynamika aerozoli w obudowie bezpieczeństwa reaktora jądrowego po awarii LOCA
Adamski J.
Zeszyty Naukowe. Elektryka / Politechnika Opolska
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2006
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Vol. 315, z. 56
19-32
PL
Przedstawiono analizę zachowania się radioaktywnych cząsteczek aerozoli, wewnątrz obudowy bezpieczeństwa, po awarii typu LOCA reaktora jądrowego. Badania dotyczą głównie zachowania się aerozoli pod wpływem koagulacji oraz usuwania i kondensacji pary na cząsteczkach aerozolowych. Analizowano koagulację Browna, grawitacyjną i turbulentną. Badano mechanizmy osadzania, spowodowane przez dyfuzję, termoforezę i dyfuzjoforezę.
EN
The main phenomena connected with transport and retention of aerosols have been described in the paper. The basic data on Brownian, gravitational, and turbulent coagulation have been presented. The principal mechanism of deposition of aerosol particles on surfaces, including sedimentation, Brownian diffusion, turbulent diffusion, and thermophoresis have been considered. Results of calculation have been shown. In the presented analysis the source term of radionuclide aerosols is due to LOCA accident.
12
Content available remote Thermophoresis free convection from a vertical cylinder embedded in a porous medium
Chamkha A. J., Jaradat M., Pop I.
International Journal of Applied Mechanics and Engineering
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2004
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Vol. 9, no 3
471-481
EN
This paper deals with the steady free convection over an isothermal vertical circular cylinder embedded in a fluid-saturated porous medium in the presence of the thermophoresis particle deposition effect. The governing partial differential equations are transformed into a set of non-similar equations, which are solved numerically using an implicit finite-difference method. Comparisons with the previously published work are performed and the results are found to be in excellent agreement. Many results are obtained and a representative set of these results is displayed graphically to illustrate the influence of the various physical parameters on the wall thermophoretic deposition velocity and concentration profiles.
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