scholarly journals A double wavelength interferometer for the study of heat and mass transfer in double diffusive systems

1990 ◽  
Author(s):  
Weimin Lu ◽  
W Worek
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Double Diffusive ◽  
Diffusive Systems

Weakly Nonlinear Double-Diffusive Oscillatory Magneto-Convection Under Gravity Modulation

2020 ◽  
Vol 18 (9) ◽  
pp. 725-738
Author(s):  
Palle Kiran ◽  
S. H. Manjula
Keyword(s):  
Mass Transfer ◽  
Prandtl Number ◽  
Gravity Field ◽  
Heat And Mass Transfer ◽  
Landau Equation ◽  
Perturbation Technique ◽  
Critical Rayleigh Number ◽  
Oscillatory Mode ◽  
Stationary Mode ◽  
Double Diffusive

An imposed time-periodic gravity field effect on double-diffusive magneto-convection for oscillatory mode has been investigated. The gravity field consisting of steady and periodic modes. A layer is confined with an electrically conducting fluid with Boussines q approximation and heated from below cooled from above. While using the perturbation technique we study nonlinear double-diffusive convection just above the critical state of the onset convection. The growth rate of the disturbances is confined with a critical Rayleigh number to investigate oscillatory convection. Analysis of finite- amplitude convection has been derived through the complex Ginzburg-Landau equation (CGLE). The convective heat and mass transfer obtained through CGLE at third-order under solvability conditions. This convective amplitude is required to estimate heat and mass transfer in terms of the Nusselt and Sherwood numbers. It is found that increasing the frequency of modulation causes diminishing heat and mass transfer. The effect of Prandtl number Pr, magnetic Prandtl number Pm, and amplitude δ enhances heat/mass transfer. It is found that an oscillatory mode of convection enhances the heat and mass transfer than the stationary mode. Further, streamlines, isotherms, and isohalines have their usual nature on double-diffusive magnetoconvection.

Numerical simulation of unsteady double-diffusive natural convection within an inclined parallelepipedic enclosure

2014 ◽  
Vol 25 (11) ◽  
pp. 1450058 ◽  
Author(s):  
Fakher Oueslati ◽  
Brahim Ben-Beya ◽  
Taieb Lili
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Three Dimensional ◽  
Transfer Rates ◽  
Flow Energy ◽  
Wide Range ◽  
Inclination Angles ◽  
Volume Method ◽  
Buoyancy Ratio ◽  
Double Diffusive

Unsteady three-dimensional (3D) double diffusive convection in tilted enclosure having a parallelepipedic shape has been analyzed numerically. The governing unsteady, 3D flow, energy and concentration transport equations, have been solved using an accelerated multigrid implicit volume method. Main attention was paid to the effects of the Rayleigh number Ra , buoyancy ratio N and the inclination angle γ of the cavity on the flow structure and heat and mass transfer rates. Typical distributions of velocity contours, temperature and concentration fields in wide range of defining parameters 103 ≤ Ra ≤ 2 × 104, -5 ≤ N ≤ 5 have been obtained. It is found, that the optimal heat and mass transfer rates for the aiding situation have been observed at two particular inclination angles namely 30° and 75° about the horizontal direction. It should be noted that the flow undergoes a periodic behavior for particular parameters Ra = 104 and γ = 75° according to the aiding flow case. The results also suggest that when N is in range -2 ≤ N ≤ -0.6, the flow continues to be three-dimensional keeping different heat and mass rates. Furthermore, it has been argued that the 2D assumption can be adopted for the 3D flows when the buoyancy ratio N is in range (-0.5–0).

Influence of viscous dissipation and thermo-diffusion on double diffusive convection over a vertical cone in a non-Darcy porous medium saturated by a non-Newtonian fluid with variable heat and mass fluxes

2018 ◽  
Vol 7 (1) ◽  
pp. 65-72
Author(s):  
Rishi Raj Kairi ◽  
Ch. RamReddy ◽  
Santanu Raut
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Differential Equations ◽  
Heat And Mass Transfer ◽  
Viscous Dissipation ◽  
Newtonian Fluid ◽  
Power Law ◽  
Vertical Cone ◽  
Variable Heat ◽  
Double Diffusive

Abstract This paper emphasizes the thermo-diffusion and viscous dissipation effects on double diffusive natural convection heat and mass transfer characteristics of non-Newtonian power-law fluid over a vertical cone embedded in a non-Darcy porous medium with variable heat and mass flux conditions. The Ostwald–de Waele power-law model is employed to describe the behavior of non-Newtonian fluid. Local non-similarity procedure is applied to transform the set of non-dimensional partial differential equations into set of ordinary differential equations and then the resulting system of equations are solved numerically by Runge-Kutta fourth order method together with a shooting technique. The influence of pertinent parameters on temperature and concentration, heat and mass transfer rates are analyzed in opposing and aiding buoyancy cases through graphical representation and explored in detail.

ISPH method for MHD double-diffusive natural convection of a nanofluid within cavity containing open pipes

2019 ◽  
Vol 30 (7) ◽  
pp. 3607-3634 ◽  
Author(s):  
Zehba A.S. Raizah ◽  
Abdelraheem M. Aly
Keyword(s):  
Mass Transfer ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Straight Pipe ◽  
Pipe Length ◽  
Content Type ◽  
Open Pipe ◽  
Double Diffusive

Purpose This paper aims to adopt incompressible smoothed particle hydrodynamics (ISPH) method for studying magnetohydrodynamic (MHD) double-diffusive natural convection from an inner open pipe in a cavity filled with a nanofluid. Design/methodology/approach The Lagrangian description of the governing equations was solved using the current ISPH method. The effects of two pipe shapes as a straight pipe and V-pipe, length of the pipe LPipe (0.2-0.8), length of V-pipe LV (0.04-0.32), Hartmann parameter Ha (40-120), solid volume fraction ϕ (0-0.1) and Lewis number Le (1-50) on the heat and mass transfer of nanofluid have been investigated. Findings The results demonstrate that the average Nusselt and Sherwood numbers are increased by increment on the straight-pipe length, V-pipe length, Hartmann parameter, solid volume fraction and Lewis number. In addition, the variation on the open pipe shapes gives a suitable choice for enhancement heat and mass transfer inside the cavity. The control parameters of the open pipes can enhance the heat and mass transfer inside a cavity. In addition, the variation on the open pipe shapes gives a suitable choice for enhancement heat and mass transfer inside the cavity. Originality/value ISPH method is developed to study the MHD double-diffusive natural convection from the novel shapes of the inner heated open pipes inside a cavity including straight-pipe and V-pipe shapes.

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