Heat and mass transfer enhancement in a double diffusive mixed convection lid cavity under pulsating flow
TL;DR: Results show that the pulsating regime enhances heat/mass transfer within a square cavity up to a 14%/38% respectively with respect to the non-pulsating case, due to the promotion of additional shear stress fields.
About: This article is published in Computers & Chemical Engineering.The article was published on 2016-11-02. It has received 15 citations till now. The article focuses on the topics: Richardson number & Combined forced and natural convection.
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TL;DR: Two major types of heat removal technics for micro-scale single-phase flow, namely passive and active type are explored, which have most important advantages are stability and robustness in operation or integration with complex systems.
39 citations
TL;DR: In this paper, the influence of the pulsation frequency on the heat transfer performance was explored and the changes of instantaneous h with frequency were further analyzed to interpret the results of the results.
Abstract: Nanofluids heat transfer in a helical coil under pulsation condition was numerically simulated. The dynamic single phase model which considered Brownian motion effect was utilized to study the Al2O3 nanofluids heat transfer in helical coils. The reliability test results were consistent with experimental results. Then, pulsation was further imposed. The influence of the pulsation frequency on the heat transfer performance was explored. And the changes of instantaneous h with frequency were further studied to interpret the results. The axial velocity contours, axial velocity distributions, and cross-section velocity vectors at various planes along the coil were examined. The results revealed that there was an optimum pulsation frequency for heat transfer augmentation within the scope of Re. The secondary flow generated in cross region and the counter-rotating vortex formed in the axial direction all devoted to the helical coil heat transfer augmentation under pulsation.
18 citations
TL;DR: In this paper, a two-way hydrogen supply mode is applied to a 10-cell open-cathode proton exchange membrane fuel cell stack to improve the water management of the stack.
16 citations
TL;DR: In this article, the authors studied the effect of thermal boundary conditions on heat transfer between two opposing vertical side walls in an inclined porous cavity with positively or negatively inclined angles, and showed that a partially active thermal boundary condition on wall B can lead to heat transfer on wall A.
Abstract: Natural convection in an inclined porous cavity with positively or negatively inclined angles is studied numerically for time-periodic boundary conditions on the left side wall and partially active thermal boundary conditions on the right wall. The results show that a partially active thermal boundary condition on wall B can lead to heat transfer between two opposing vertical side walls. Temperature locations on wall B have significant effects on heat transfer of wall B, but weak effects on that of wall A. Compared with the uniform thermal boundaries, the non-uniform temperature distributions on wall B can reduce the oscillation amplitude of NuB. The absolute value of Nuav for the uniform boundary condition on wall B is highest when |φ| > 30° and the differences of Nuav between different boundary conditions on wall B decrease with the increasing of |φ|.
14 citations
TL;DR: In this paper, double-diffusive mixed convection in a closed rectangular cavity filled with non-Newtonian power-law fluid and subjected to uniform heat and mass fluxes from its vertical short sides was investigated.
11 citations
References
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Book•
27 Jul 1982
TL;DR: Properties of Gases Uniform Particle Motion Particle size Statistics Straight-Line Acceleration and Curvilinear Particle motion Adhesion of Particles Brownian Motion and Diffusion Thermal and Radiometric Forces Filtration Sampling and Measurement of Concentration Respiratory Deposition Coagulation Condensation and Evaporation Atmospheric Aerosols Electrical Properties Optical Properties Bulk Motion of aerosols Dust Explosions Bioaerosols Microscopic measurement of Particle Size Production of Test aerosols Appendices Index Index
Abstract: Properties of Gases Uniform Particle Motion Particle Size Statistics Straight-Line Acceleration and Curvilinear Particle Motion Adhesion of Particles Brownian Motion and Diffusion Thermal and Radiometric Forces Filtration Sampling and Measurement of Concentration Respiratory Deposition Coagulation Condensation and Evaporation Atmospheric Aerosols Electrical Properties Optical Properties Bulk Motion of Aerosols Dust Explosions Bioaerosols Microscopic Measurement of Particle Size Production of Test Aerosols Appendices Index
5,208 citations
Book•
01 Jan 1984
TL;DR: In this paper, the authors describe a transition from Laminar boundary layer flow to Turbulent Boundary Layer flow with change of phase Mass Transfer Convection in Porous Media.
Abstract: Fundamental Principles Laminar Boundary Layer Flow Laminar Duct Flow External Natural Convection Internal Natural Convection Transition to Turbulence Turbulent Boundary Layer Flow Turbulent Duct Flow Free Turbulent Flows Convection with Change of Phase Mass Transfer Convection in Porous Media.
4,067 citations
Book•
01 Jan 1999
TL;DR: Aerosol Technology, Second Edition as mentioned in this paper is the #1 guide to aerosol science and technology and has been the text of choice among students and professionals who need to acquire a thorough working knowledge of modern aerosol theory and applications.
Abstract: The #1 guide to aerosol science and technology -now better than everSince 1982, Aerosol Technology has been the text of choice among students and professionals who need to acquire a thorough working knowledge of modern aerosol theory and applications. Now revised to reflect the considerable advances that have been made over the past seventeen years across a broad spectrum of aerosol-related application areas - from occupational hygiene and biomedical technology to microelectronics and pollution control -this new edition includes:* A chapter on bioaerosols* New sections on resuspension, transport losses, respiratory deposition models, and fractal characterization of particles* Expanded coverage of atmospheric aerosols, including background aerosols and urban aerosols* A section on the impact of aerosols on global warming and ozone depletion.Aerosol Technology, Second Edition also features dozens of new, fully worked examples drawn from a wide range of industrial and research settings, plus new chapter-end practice problems to help readers master the material quickly.
3,237 citations
TL;DR: In this article, it has been shown that the simultaneous presence of two components with different diffusivities can lead to a whole range of new phenomena, and these form the subject of the present review.
Abstract: The study of convective motions produced by unstable density distributions in a fluid is now highly developed. Most attention has been given to the case of a thin horizontal layer of fluid, heated below and cooled above, and results obtained using a combination of Boussinesq theory and laboratory experiments have been success fully applied in many contexts (Chandrasekhar 1961, Spiegel 1971). The problem of buoyant convection from isolated sources has also been extensively studied (Turner 1969). Though the effect of adding other processes, such as rotation and magnetic fields, to the buoyant motion has been considered (Spiegel 1972), it has been assumed that the driving density differences are produced by the spatial variations of a single diffusing property (such as heat or a solute). Comparatively recently it has been shown that the simultaneous presence of two components with different diffusivities can lead to a whole range of new phenomena, and these form the subject of the present review. A striking feature of many systems of interest is that instabilities can develop even when the net density decreases upwards. Diffusion, which is generally stabilizing in a fluid containing a single solute, can now act so as to allow the release of the potential energy in the component that is heavy at the top. Much of this work was initiated with an application to the ocean in mind, and because heat and salt (or some other dissolved substance) are then important, the process has been called thermohaline (or thermosolutal) convection. Related effects have now been observed in other contexts, to be described below, and the name double-diffusive convection has been used to encompass this wider range of phenomena. The minimum requirements for the occurrence of double-diffusive convection, in the sense implied here, are the following: (i) The fluid must contain two or more components having different molecular diffusivities. It is the differential diffusion that produces the density differences required to drive the motion. (ii) The components must make opposing contributions to the vertical density gradient. (It is assumed throughout that the fluids are completely miscible, so that surface-tension effects do not arise. Some of the motions produced by the Marangoni
410 citations