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local-thermal-equilibrium
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Unsaturated thermal consolidation around a heat source
, Article Computers and Geotechnics ; Volume 134 , 2021 ; 0266352X (ISSN) ; Ghasemi Fare, O ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Thermal loadings in saturated (two-phase) clays induce excess pore water pressure due to the difference in the thermal expansion coefficient of the pore volume and the pore water. The gradual dissipation of the excess pore water pressure causes thermal volume reduction which is known as thermal consolidation. However, thermal consolidation in a three-phase soil system such as unsaturated soil is more sophisticated. In this paper, an analytical model for thermal consolidation around a heat source embedded in unsaturated clay or in calyey soils containing two immiscible fluids is developed based on the effective stress concept. Governing equations, including energy, mass, and momentum balance...
A numerical analysis of thermal conductivity, thermal dispersion, and structural effects in the injection part of the resin transfer molding process
, Article Journal of Porous Media ; Volume 13, Issue 4 , 2010 , Pages 375-385 ; 1091028X (ISSN) ; Karimi, M ; Seyf, H. R ; Sharif University of Technology
2010
Abstract
Thermal conductivity, thermal dispersion, and structural effects in resin transfer molding (RTM) process are studied numerically. The injection part of the RTM process is modeled as a transport of resin flow through a fibrous porous medium in a long rectangular channel. The fluid flow is modeled using the Darcy-Brinkman-Forchheimer model and the heat transfer process using the energy equation based on local thermal equilibrium assumption. Both isotropic and anisotropic heat transfer in porous media are investigated. The governing equations are solved numerically for the isotropic heat transfer case and analytically for the anisotropic case. The numerical results are fitted to the available...
Modeling of Fluid Flow and Heat Transfer at the Entrance Zone of a Partially Filled Porous Channel
, M.Sc. Thesis Sharif University of Technology ; Nouri Borujerdi, Ali (Supervisor)
Abstract
This paper numerically studies the convection heat transfer enhancement of a developing two dimensional laminar flow in a pipe partially filled with porous materials. One of the most important effects of the systems with porous materials in them, is that they can improve some heat transfer components if they be used in a proper way. This study has been performed under both local thermal equilibrium (LTE) and local thermal non-equilibrium (LTNE) conditions. Two energy equations are used in non-thermal equilibrium condition between fluid and porous material. Darcy-Brinkman-Forchheimer model is used to model the flow inside the porous medium. The effects of different parameters such as, Darcy...
Simulation of Regenerator in a Pulse Tube Refrigerator and Comparison of Performance in Two Conditions of Thermally Equilibrium and Thermally Non-Equilibrium
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
Pulse tube refrigerator due to the relatively high efficiency, high reliability of linear compressor and the absence of moving parts in the cold area is known as one of the best options to generate up to one kW of cooling power at temperatures from 4 to 123 K. More recently, the use of the device at a temperature of about 150 K, makes use of it even outside of cryogenic temperature. The most important part of the device is regenerator, so understanding the nature of the flow and interaction of gas and solid network in the retrievers is necessary. In this study, Inertance pulse tube refrigerator (IPTR) is simulated using Ansys Fluent in two different conditions. In the first condition the...
Performance of Partially Filled Mini-Channels with Porous Media
, M.Sc. Thesis Sharif University of Technology ; Nouri, Ali (Supervisor) ; Moosavi, Ali (Co-Advisor)
Abstract
Laminar forced convection flow through a channel partially filled with a porous material was numerically studied in this thesis. The Navier-Stokes and Brinkman-Forchheimer equations were used to model the fluid flow in the free and porous regions, respectively. Coupling of the pressure and velocity fields was resolved using the SIMPLEC algorithm. The local thermal equilibrium was adopted in the energy equation. The effects of the thermal conductivity ratio, Darcy number, porosity, Reynolds number and height of the porous insert on velocity and temperature field were investigated. The results show that the flow behavior and its associated heat transfer are susceptible to the variation of the...
Mixed-convection flow of Al2O3-H2O nanofluid in a channel partially filled with porous metal foam: Experimental and numerical study
, Article Experimental Thermal and Fluid Science ; Vol. 53 , February , 2014 , pp. 49-56 ; ISSN: 08941777 ; Molaei Dehkordi, A ; Sharif University of Technology
Abstract
Mixed-convection flow of nanofluids inside a vertical rectangular channel partially filled with open-cell metal foam and subject to a constant wall-heat flux was investigated experimentally and numerically. Al2O3-water nanofluids with different concentrations were prepared and their stability was examined using UV-Vis spectroscopy. Dynamic light scattering method was used to determine particle size distribution of the nanofluid feedstock. The outlet temperature and pressure drop were measured for different nanofluid flow rates (i.e., Reynolds number values). In the numerical section, a two-dimensional volume-averaged form of the governing equations was used. The velocity and temperature...