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Comparative Study on Effects of Thermal Gradient Direction on Heat Exchange between a Pure Fluid and a Nanofluid: Employing Finite Volume Method. COATINGS 2021. [DOI: 10.3390/coatings11121481] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This work aims to determine how the temperature gradient orientation affects the heat exchange between two superposed fluid layers separated by zero wall thickness. The finite volume method (FVM) has been developed to solve the governing equations of both fluid layers. To achieve the coupling between the two layers, the heat flow continuity with the no-slip condition at the interface was adopted. The lower part of the space is filled with a nanofluid while the upper part is filled with a pure fluid layer. We have explored two cases of temperature gradient orientation: parallel gradient to gravity forces of our system and perpendicular gradient to gravity forces. We took a set of parameters, Ri and ϕ, to see their influence on the thermal and hydrodynamic fields as well as the heat exchange rate between the two layers. The main applications of this study related to biological systems such as the cytoplasm and the nucleoplasm are phase-separated solutions, which can be useful as models for membranelles organelles and can serve as a cooling system application using heat exchange. The Richardson number and the volume of nanosolid particles have a big impact on the rate of change of heat transmission. When a thermal gradient is perpendicular to gravity forces, total heat transmission improves with increasing solid volume percentage, but when the thermal gradient is parallel to gravity forces, overall heat transfer decreases significantly.
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Nakamura K, Yoshikawa HN, Tasaka Y, Murai Y. Linear stability analysis of bubble-induced convection in a horizontal liquid layer. Phys Rev E 2020; 102:053102. [PMID: 33327120 DOI: 10.1103/physreve.102.053102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/15/2020] [Indexed: 06/12/2023]
Abstract
We investigate with a linear analysis the stability of a horizontal liquid layer subjected to injection of gas bubbles through a bottom wall. The injection is assumed uniform in space and constant in time. Injected bubbles ascend in the liquid layer due to the Archimedean buoyancy force and are ejected from the top free surface of the liquid layer. Modeling this two-phase flow system as two interpenetrating liquid and gas continua, we show that homogeneous upward gas flows become unstable at large gas fluxes. We determine the critical conditions of this homogeneous-heterogeneous regime transition and show that the critical modes are made of stationary convection rolls, either multi- or whole-layered depending on liquid viscosity, the radius of bubbles, and the thickness of liquid layer. By examining the energy transfer from base to perturbation flows, we indicate that liquid convective motion is driven by the buoyancy on heterogeneously distributed bubbles. We also reveal that the lift forces on bubbles have significant stabilizing effects by homogenizing bubble distribution close to the bottom wall.
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Affiliation(s)
- Kotaro Nakamura
- Laboratory for Flow Control, Hokkaido University, Sapporo, Japan
| | | | - Yuji Tasaka
- Laboratory for Flow Control, Hokkaido University, Sapporo, Japan
| | - Yuichi Murai
- Laboratory for Flow Control, Hokkaido University, Sapporo, Japan
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LIP formation and protracted lower mantle upwelling induced by rifting and delamination. Sci Rep 2018; 8:16578. [PMID: 30410091 PMCID: PMC6224380 DOI: 10.1038/s41598-018-34194-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/12/2018] [Indexed: 11/08/2022] Open
Abstract
Large Igneous Provinces (LIPs) are commonly attributed to mantle plumes, hot upwellings from the deep lower mantle, apparently unrelated to plate motions. However, LIPs often form in association with rifting and breakup. Using numerical modelling, we introduce a novel idea that explains plume-like mantle upwelling by plate tectonic processes. Our model indicates that rifting-induced delamination of orogenic lithosphere can perturb the thermochemical mantle stratification and induce lower mantle upwelling which causes syn-rift LIP formation followed by protracted and enhanced mid ocean ridge basalt (MORB) generation. Our model provides an explanation for the geographical correlation between the Caledonian suture, the North Atlantic Igneous Province (NAIP) and present-day Icelandic magmatism.
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Christensen UR, Yuen DA. The interaction of a subducting lithospheric slab with a chemical or phase boundary. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb089ib06p04389] [Citation(s) in RCA: 310] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Spohn T, Schubert G. Modes of mantle convection and the removal of heat from the Earth's interior. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb087ib06p04682] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Olson P, Kincaid C. Experiments on the interaction of thermal convection and compositional layering at the base of the mantle. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/90jb02530] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Glatzmaier GA, Schubert G. Three-dimensional spherical models of layered and whole mantle convection. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/93jb02111] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Roufosse MC, Jeanloz R. Thermal conductivity of minerals at high pressure: The effect of phase transitions. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb088ib09p07399] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Watt JP, Ahrens TJ. The role of iron partitioning in mantle composition, evolution, and scale of convection. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb087ib07p05631] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Davies GF. Geophysical and isotopic constraints on mantle convection: An interim synthesis. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb089ib07p06017] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gyüre B, Jánosi IM. Basics of lava-lamp convection. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:046307. [PMID: 19905436 DOI: 10.1103/physreve.80.046307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Indexed: 05/28/2023]
Abstract
Laboratory experiments are reported in an immiscible two-fluid system, where thermal convection is initiated by heating at the bottom and cooling at the top. The lava-lamp regime is characterized by a robust periodic exchange process where warm blobs rise from the bottom, attach to the top surface for a while, then cold blobs sink down again. Immiscibility allows to reach real steady (dynamical equilibrium) states which can be sustained for several days. Two modes of lava-lamp convection could be identified by recording and evaluating temperature time series at the bottom and at the top of the container: a "slow" mode is determined by an effective heat transport speed at a given temperature gradient, while a second mode of constant periodicity is viscosity limited. Contrasting of laboratory and geophysical observations yields the conclusion that the frequently suggested lava-lamp analogy fails for the accepted models of mantle convection.
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Affiliation(s)
- Balázs Gyüre
- von Kármán Laboratory of Environmental Flows, Loránd Eötvös University, Budapest, Hungary
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Davaille A. Simultaneous generation of hotspots and superswells by convection in a heterogeneous planetary mantle. Nature 1999. [DOI: 10.1038/45461] [Citation(s) in RCA: 326] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shen Y, Solomon SC, Bjarnason IT, Wolfe CJ. Seismic evidence for a lower-mantle origin of the Iceland plume. Nature 1998. [DOI: 10.1038/25714] [Citation(s) in RCA: 183] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ogawa M, Nakamura H. Thermochemical regime of the early mantle inferred from numerical models of the coupled magmatism-mantle convection system with the solid-solid phase transitions at depths around 660 km. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98jb00611] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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The temperature contrast across D″. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/gd028p0073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
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Williams Q, Jeanloz R. Melting relations in the iron-sulfur system at ultra-high pressures: Implications for the thermal state of the Earth. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/jb095ib12p19299] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Cserepes L, Rabinowicz M, Rosemberg-Borot C. Three-dimensional infinite Prandtl number convection in one and two layers with implications for the Earth's gravity field. ACTA ACUST UNITED AC 1988. [DOI: 10.1029/jb093ib10p12009] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Ultrahigh-pressure phase transformations and the constitution of the deep mantle. ACTA ACUST UNITED AC 1987. [DOI: 10.1029/gm039p0221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Theoretical study of the structural properties and equations of state of MgSiO3 and CaSiO3 perovskites: Implications for lower mantle composition. ACTA ACUST UNITED AC 1987. [DOI: 10.1029/gm039p0313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Mineralogy of mantle peridotite along a model geotherm up to 700 Km depth. ACTA ACUST UNITED AC 1987. [DOI: 10.1029/gm039p0427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Abstract
Temperatures of equilibration for the majority (81 percent) of the eclogite xenoliths of the Roberts Victor kimberlite pipe in South Africa range between 1000 degrees and 1250 degrees C, falling essentially on the gap of the lower limb of the subcontinental inflected geotherm derived from garnet peridotite xenoliths. In view of the Archean age (>2.6 x 10(9) years) of these eclogites and their stratigraphic position on the geotherm, it is proposed that the inflected part of the geotherm represents the convective boundary layer beneath the conductive lid of the lithospheric plate. The gradient of 8 Celsius degrees per kilometer for the inflection is characteristic of a double thermal boundary layer and suggests layered convection rather than whole mantle convection for the earth.
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Abstract
The independent growth of the various branches of the earth sciences in the past two decades has led to a divergence of geophysical, geochemical, geological, and planetological models for the composition and evolution of a terrestrial planet. Evidence for differentiation and volcanism on small planets and a magma ocean on the moon contrasts with hypotheses for a mostly primitive, still undifferentiated, and homogeneous terrestrial mantle. In comparison with the moon, the earth has an extraordinarily thin crust. The geoid, which should reflect convection in the mantle, is apparently unrelated to the current distribution of continents and oceanic ridges. If the earth is deformable, the whole mantle should wander relative to the axis of rotation, but the implications of this are seldom discussed. The proposal of a mantle rich in olivine violates expectations based on evidence from extraterrestrial sources. These and other paradoxes force a reexamination of some long-held assumptions.
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Parsons B, Daly S. The relationship between surface topography, gravity anomalies, and temperature structure of convection. ACTA ACUST UNITED AC 1983. [DOI: 10.1029/jb088ib02p01129] [Citation(s) in RCA: 200] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kenyon PM, Turcotte DL. Convection in a two-layer mantle with a strongly temperature-dependent viscosity. ACTA ACUST UNITED AC 1983. [DOI: 10.1029/jb088ib08p06403] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lees AC, Bukowinski MST, Jeanloz R. Reflection properties of phase transition and compositional change models of the 670-km discontinuity. ACTA ACUST UNITED AC 1983. [DOI: 10.1029/jb088ib10p08145] [Citation(s) in RCA: 151] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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