Double Diffusion Effects on Entropy Generation in Convective Heat and Mass Transfer

Purpose This paper aims to present the effect of entropy generation on the unsteady flow of upper-convected Maxwell nanofluid past a wedge embedded in a porous medium in view of buoyancy force. Cattaneo-Christov double diffusion theory simulates the processes of energy phenomenon and mass transfer. Meanwhile, Brownian motion, thermophoresis and convective boundary conditions are discussed to further visualize the heat and mass transfer properties. Design/methodology/approach Coupled ordinary differential equations are gained by appropriate similar transformations and these equations are manipulated by the Homotopy analysis method. Findings The result is viewed that velocity distribution is a diminishing function with boosting the value of unsteadiness parameter. Moreover, fluid friction irreversibility is dominant as the enlargement in Brinkman number. Then controlling the temperature and concentration difference parameters can effectively regulate entropy generation. Originality/value This paper aims to address the effect of entropy generation on unsteady flow, heat and mass transfer of upper-convected Maxwell nanofluid over a stretched wedge with Cattaneo-Christov double diffusion, which provides a theoretical basis for manufacturing production.

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Double Diffusive Magnetohydrodynamic (MHD) Natural Convection and Entropy Generation in a Discretely Heated Inclined Dome-Shaped Enclosure Filled with Cu-Water Nanofluid

Journal of Nanofluids ◽

10.1166/jon.2021.1799 ◽

2021 ◽

Vol 10 (4) ◽

pp. 564-579

Author(s):

Rujda Parveen ◽

Priyajit Mondal ◽

Tapas Ray Mahapatra

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Mass Transfer ◽

Heat And Mass Transfer ◽

Convective Heat ◽

Entropy Generation ◽

Inclination Angle ◽

Hartmann Number ◽

Substantial Impact ◽

Double Diffusive

This research presents an investigation of laminar two-dimensional double-diffusive free convection and entropy formation in an inclined enclosure under the influence of an inclined magnetic field. The performance of natural convective heat transfer can be improved by doing modifications in enclosure geometry that impact the flow structure. We have considered a dome-shaped enclosure to examine the heat and mass transfer performance. The enclosure is saturated with Cu-water nanofluid and the two sidewalls of the enclosure are maintained at constant temperature Tc(<Th) and concentration cc(<ch). The top-curved wall is adiabatic, and the lower wall is discretely heated and concentrated. The governing equations are first non-dimensionalized and then written in stream function-velocity formulation that is solved numerically using the Bi-CGStab method. A comparison with previously published work in literature is presented and found to be in excellent agreement. Numerical simulations are performed for various values of considered parameters such as Rayleigh number (Ra), Hartmann number (Ha), the orientation of magnetic field (γ), volume fraction of nanoparticles (Φ), and inclination angle of the enclosure (δ). The mentioned parameters have a substantial impact on the cavity flow characteristics. The obtained results demonstrate that the average Sherwood number and Nusselt number are decreasing functions of both the Hartmann number and inclination angle of the enclosure. The minimum heat and mass transfer took place at δ = 135° as the angle of inclination of the enclosure restrains the fluid velocity and reduces the heat transfer rate. Also, entropy generation analysis is conducted for all the considered parameters. The results show that the dome-shaped enclosure has a substantial impact on the fluid flow that enables a smoother and more effective flow inside the cavity, which improves the natural convective heat and mass transmission.

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Entropy Generation in Convective Heat Transfer and Isothermal Convective Mass Transfer

Journal of Heat Transfer ◽

10.1115/1.3248137 ◽

1987 ◽

Vol 109 (3) ◽

pp. 647-652 ◽

Cited By ~ 79

Author(s):

J. Y. San ◽

W. M. Worek ◽

Z. Lavan

Keyword(s):

Heat Transfer ◽

Mass Transfer ◽

Boundary Conditions ◽

Convective Heat Transfer ◽

Heat And Mass Transfer ◽

Convective Heat ◽

Entropy Generation ◽

Ideal Gas ◽

Convective Mass Transfer ◽

Plate Spacing

The irreversible generation of entropy for two limiting cases of combined forced-convection heat and mass transfer in a two-dimensional channel are investigated. First, convective heat transfer in a channel with either constant heat flux or constant surface temperature boundary conditions are considered for laminar and turbulent flow. The entropy generation is minimized to yield expressions for optimum plate spacing and optimum Reynolds numbers for both boundary conditions and flow regimes. Second, isothermal convective mass transfer in a channel is considered, assuming the diffusing substance to be an ideal gas with Lewis number equal to unity. The flow is considered to be either laminar or turbulent with boundary conditions at the channel walls of either constant concentration or constant mass flux. The analogy between heat and mass transfer is used to determine the entropy generation and the relations for optimum plate spacing and Reynolds number. The applicable range of the results for both limiting cases are then investigated by non-dimensionalizing the entropy generation equation.

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MHD and Double Diffusion Effects on Heat and Mass Transfer in Non-Darcy Fluid Flows Over a Vertical Plate

Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D ◽

10.1115/imece2012-85225 ◽

2012 ◽

Author(s):

A. S. N. Murti ◽

P. K. Kameswaran ◽

T. Poorna Kantha ◽

A. A. V. L. A. S. Acharyulu

Keyword(s):

Mass Transfer ◽

Heat And Mass Transfer ◽

Vertical Plate ◽

Fluid Flows ◽

Double Diffusion ◽

Integration Scheme ◽

Physical Parameters ◽

Transfer Rates ◽

Linear Partial Differential Equations ◽

Diffusion Effects

In the present paper we investigate double diffusion effects on mixed convective heat and mass transfer over a Newtonian vertical plate. Diffusion and chemical reaction terms are considered in the energy and concentration equations. A similarity transformation was used to convert governing non linear partial differential equations into ordinary. The dimensionless governing equations are solved numerically by using fourth-order Runge–Kutta integration scheme along with shooting technique. Detailed results for various physical parameters like velocity, temperature and concentration fields as well as the heat and mass transfer rates have been presented. In the absence of Magnetic and double diffusion effects our results are good in agreement with the results in the literature.

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