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Dynamic thermal performance of multilayer hollow clay walls filled with insulation materials:Toward energy saving in hot climates

2011 SSITE International Conference on Future Material Research and Industry Application(FMRIA 2011)

The investigation was to study the effect of laminar-turbulent transition on predicting thermal load of vaneThe Abu-Ghannam and Shaw（AGS） algebraic transition model was applied in the coupled solver, HIT3 DThen the solver was employed to carry out coupled heat transfer simulations, and the test case was 5411 run of NASA0-MARKⅡ vane, a high-pressure turbine vaneThe results shown that AGS model was able to predict the transition process in the boundary layer near the vane, and that the simulation with such model leads to thermal load agreeing well the measured oneThen the developed solver was applied to predict a low-pressure vane, and the results shown that CHT simulation with full turbulence model would predict higher thermal load than that with transition model.

关键词： turbine coupled heat transfer transition flow boundary layer flows thermal load

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Energy and Built Environment

Energy and Built Environment 2024年第1期5卷 70-80页

作者： Yassine Chihab Mohammed Garoum Najma Laaroussi Mohammed V University in Rabat MaterialsEnergy and Acoustics TEAMRabatMorocco

This study examines the benefits of incorporating passive techniques into multilayer hollow clay brick walls to improve their dynamic thermal *** finite element approach was used to solve the incompressible Navier-Stokes and energy equations to analyze the dynamic thermal response of walls exposed to real thermal excitations of the Marrakesh *** results show that increasing the emissivity from 0.1 to 0.9 significantly increases the total heat load over 24 ***,filling 100% of the cavities with insulation materials delayed the temperature peak by about 2.3 h and lowered the decrement factor by roughly 43%,with a value smaller than *** addition,it is demonstrated that the total thermal load is reduced by approximately 28% for improved wall configurations(100% insulation filling cavities)compared to traditional wall configurations(100% air filling cavities),which aids in improving building energy efficiency.

关键词： Time lag Decrement factor coupled heat transfer Analytical solution Hollow clay brick Insulation filling cavities Energy savings in building

Rotation Effect on Flow and heat transfer for High-Temperature Rotor Blade in a Heavy Gas Turbine

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Journal of Thermal Science 2021年第2期30卷 707-715页

作者： DONG Aihua YAN Peigang QIAN Xiaoru HAN Wanjin WANG Qingchao School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Harbin Turbine Company Limited Harbin 150046China

In this paper,the composite inner cooling structures of the rotating blade in the first stage heavy gas turbine were modeled and simulated by coupling heat transfer (CHT).The flow characteristics and heat transfer performances were comparatively analyzed under two operations of the stationary and the rotational *** results show that the turbulence intensity,the flow resistance and the heat transfer level of the rotating coolant are significantly increased compared with the stationary state,which is considered to be obtained by the combined effects of the Coriolis force,the centrifugal force and their derived buoyancy *** is pointed out that the rotation leads to the non-uniform flow of film holes at the leading edge of the pressure surface along blade *** addition,it increases the slope of the limiting streamline,which has a decisive influence on the heat transfer of both the pressure and suction *** paper provides guidance for the design of a rotating composite cooling structure based on the relations between the stationary and rotational conditions.

关键词： heavy gas turbine composite cooling structure coupled heat transfer rotation effect simulation

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Transient Radiation-Conductive heat transfer Problems:"The Quadrupole Method"

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Journal of Thermal Science 2002年第4期11卷 359-371页

作者： Alain Degiovanni Benjamin Remy Stephane Andre Laboratoire d'Energetique et de Mecanique Theorique et Appliquee L.E.M.T.A-U.M.R C.N.R.S 7563/E.E.I.G.M-E.N.S.E.MUniversite Henri Poincare-Nancy IInstitut National Polytechnique de Lorraine(I.N.P.L)02avenue de la Foret de Haye-B.P 16054516 Vandoeuvre-Les-Nancy CedexFrance

This paper presents a statement of the works performed in L.E.M.T.A by the members of the thermal and mechanical heterogeneous media research group during the last six years concerning the solving of coupled conductive and radiative heat transfers within a multilayer and semi-transparent“wall”.Out of the authors,this paper allows to take inspiration from the works of ***,*** and ***[19,20,21].The aim of these works is to represent in a macroscopic way,with the minimum number of thermophysical parameters,the heat transfers in a plane system composed of semi-transparent *** approach we propose is semi-analytic(Kernel substitution technique,Laplace transformation)and allow to obtain in the Laplace domain an analytical solution that can be easily *** method can be applied in two main scopes of applications:the estimation of thermophysical properties(phononic conductivity,optical thickness,Planck number for instance)of semi-transparent materials(glasses,crystals,glass wool,semi-conductors,synthetic diamonds,vitroceramics and so on)and the modelling of processes with semitransparent walls(for instance bottles forming,flat glass production,drying of paper).The method will be first presented and validated and two examples of applications will be then *** method can be applied to semitransparent walls that emit,absorb and scatter the radiant energy(participating medium).It appears from the principle of a Kernel substitution technique applied to the radiative flux expression and initially introduced by Lick[1]that allows to change the character of the governing heat equation from the integro-differential form to a purely differential *** the case of limiting cases of purely scattering and purely absorbing media,the solution of the radiative transfer equation is *** the general case,we make a two-flux *** all cases,we assume a linear transfer and use the Laplace *** method can be applied to grey or grey by bands

关键词： heat conduction thermal radiation coupled heat transfer quadrupole method

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Transient coupled Radiative and Conductive heat transferin a Composite of Semitransparent Media

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Journal of Thermal Science 1999年第2期8卷 131-142页

作者： Ping－YangWang He－PingTan 等 SchoolofEnergyScienceandEngineering HarbinInstituteofTechnologyHarbin150001China SchoolofEnergyScie

The transient coupled radiative and conductive heat transfer in a semitransparent composite under the complexboundary conditidns is investigated by the ray tracing method in combination with Hottel’s zonal method and thecontrol-volume method. The composite is composed of tWo plane layers of nonscattering sendtransparent media withthe different thermophysical Properties in each layer. Both boundals surfaces and the internal interface aresemitransparent. The reflections are assUmed diffuse or specular. The transient temperature distributions in thecomposite are Obtained for the combined thermal boundary conditions of incident radiation and convective heat *** diffuse reflection, the resultS in this paper are separately compared with the steady and transient results ofPrevious work. The comparison shows the reliability and the high calculating accuracy of the formulas derived in thespaper. The Present analysis includes the effeCts of the optical thickness, the conduchon-radiation parameter, the spectralproperty and the renechve mode on the transient temperature distributions.

关键词： semitransparent composite coupled heat transfer ray tracing method Hottel's zonal method

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NUMERICAL INVESTIGATION ON THE PHASE CHANGE OF WATER-SATURATED POROUS MEDIA WITH THERMOSYPHON

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2000年第2期 12-18页

作者：吴存真潘阳秦悦慧

Numerical investigations were carried out to determine the coupled heat transfer of water saturated porous media with a two phase closed thermosyphon for soil freezing, and to examine the characteristics of the freezing heat transfer in the water saturated porous media. The whole control volume includes the thermosyphon and the porous media. The two dimensional governing equations for the water saturated porous media are used. The conjugation of heat transfer between the thermosyphon and porous media is reflected through thermal balance between the thermosyphon and the porous media. The finite difference method was used to solve the two\|dimensional governing equation for the water saturated porous media and the heat transfer characteristics of the thermosyphon, obtain the flow fields and the temperature distributions in the soil. This paper deals mainly with the effect of some factors (such as soil properties, climate and thermosyphon dimensions) on the heat transfer rate of the thermosyphon and the growth of the freezing front. The predictions of the present study agree well with the measured data.

关键词： thermosyphon water saturated porous soil freezing coupled heat transfer