scholarly journals The Two-Dimensional Heat Transfer Analysis in Arrayed Fins with the Thermal Dissipation Substrate

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Hai-Ping Hu
Keyword(s):  
Heat Transfer ◽  
Thermal Dissipation ◽  
Heat Transfer Analysis ◽  
Dimensionless Temperature ◽  
Two Dimensional ◽  
Governing Equations ◽  
Point Matching ◽  
Truncation Method ◽  
Laplace Equations ◽  
Series Truncation Method

The aim of the present study is to investigate the two-dimensional heat transfer analysis in arrayed fins with thermal dissipation substrate. The governing equations for the fins and the substrate are expressed with Laplace equations, and the boundary conditions around the fins and substrate are Robin conditions. The present investigation first aims to provide a solution with regard to the geometry models by a series truncation method. Then the research will compare the results of the series truncation method with the point-matching method. Furthermore, the present study will also discuss the effects of dimension and Biot number of the fins on local dimensionless temperature, mean temperature, and heat transfer rate.

A two-dimensional heat transfer analysis of the thermal-trap collector

Solar Energy ◽  
1988 ◽  
Vol 40 (2) ◽  
pp. 127-133 ◽  
Author(s):  
N.E. Wijeysundera ◽  
V. Thevendran
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Analysis ◽  
Two Dimensional

scholarly journals Radiative heat transfer analysis by the Radiative Heat Ray method (Analysis in a two-dimensional model)

1986 ◽  
Vol 52 (476) ◽  
pp. 1734-1740 ◽  
Author(s):  
Hiroshi HAYASAKA ◽  
Kazuhiko KUDO ◽  
Hiroshi TANIGUCHI ◽  
Ichiro NAKAMACHI ◽  
Toshiaki OMORI ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Heat Transfer Analysis ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Ray Method ◽  
Two Dimensional Model ◽  
Method Analysis

Heat Transfer Analysis of a Finned Solar Air Heater

1988 ◽  
Vol 110 (2) ◽  
pp. 145-155 ◽  
Author(s):  
F. Issacci ◽  
Y. Zvirin ◽  
G. Grossman
Keyword(s):  
Heat Transfer ◽  
Theoretical Method ◽  
Lower Surface ◽  
Temperature Fields ◽  
Heat Transfer Analysis ◽  
Solar Air Heater ◽  
Governing Equations ◽  
Reversed Flow ◽  
Air Heater ◽  
Transfer Processes

A theoretical method is presented for the investigation of a reflective fin solar air heater. The heat transfer processes include radiation in both the solar and IR spectra, mixed convection (forced and natural) in the air and conduction in the fins. The governing equations have been solved numerically to obtain the velocity and temperature fields in the developing and developed flow regions. The efficiency of the finned structure is then calculated, and the results of a parametric study are shown. It has been found that natural convection effects are significant and strong buoyancy leads to separation and reversed flow. The efficiency increases with lower surface emissivity and lower thermal conductivity of the fins.

scholarly journals Two-dimensional heat transfer analysis of timber structure walls filled with hemp-lime composite

2019 ◽  
Vol 252 ◽  
pp. 05015 ◽  
Author(s):  
Przemysław Brzyski ◽  
Sylwia Duda ◽  
Andrzej Raczkowski
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Timber Structure ◽  
Heat Transfer Analysis ◽  
Two Dimensional ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Thermal Insulating ◽  
Frame Construction ◽  
Industrial Hemp

Hemp-lime composite is a thermal insulating material used as a filling in timber frame construction walls. It is a material based on the wooden part of industrial hemp stalk (hemp shives) and lime binder. In practice, different wall thicknesses, composites with different thermal properties and various configurations of timber structure are used. These factors affect the temperature distribution in the wall. In the thermally weaker areas of walls, there is a greater risk of condensation and mould growth. This issue is important while designing walls based on organic materials. The paper presents the two-dimensional (2D) heat-transfer analysis based on the finite-element method, using THERM software. Several variants of external walls were adopted for the analysis. Thermal parameters of hemp-lime composites used in the analysis were obtained from our own research. The results of the analysis were presented as the values of the thermal transmittance coefficient and linear thermal transmittance equivalent to timber construction. The temperature distribution for an exemplary wall was also shown graphically in the form of isotherms and colour-flooded isotherms.

Two-Dimensional Analysis of Conduction-Controlled Rewetting With Precursory Cooling

1976 ◽  
Vol 98 (3) ◽  
pp. 407-413 ◽  
Author(s):  
S. S. Dua ◽  
C. L. Tien
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Dimensional Analysis ◽  
Vertical Surface ◽  
Dimensionless Temperature ◽  
Two Dimensional ◽  
Dimensional Solution ◽  
One Dimensional ◽  
The One

This paper presents a two-dimensional analysis of the effect of precursory cooling on conduction-controlled rewetting of a vertical surface, whose initial temperature is higher than the sputtering temperature. Precursory cooling refers to the cooling caused by the droplet-vapor mixture in the region immediately ahead of the wet front, and is described mathematically by two dimensionless constants which characterize its magnitude and the region of influence. The physical model developed to account for precursory cooling consists of an infinitely extended vertical surface with the dry region ahead of the wet front characterized by an exponentially decaying heat flux and the wet region behind the moving film-front associated with a constant heat transfer coefficient. Apart from the two dimensionless constants describing the extent of precursory cooling, the physical problem is characterized by three dimensionless groups: the Peclet number or the dimensionless wetting velocity, the Biot number and a dimensionless temperature. Limiting solutions for large and small Peclet numbers have been obtained utilizing the Wiener-Hopf technique coupled with appropriate kernel substitutions. A semiempirical matching relation is then devised for the entire range of Peclet numbers. Existing experimental data with variable flow rates at atmospheric pressure are very closely correlated by the present model. Finally a comparison is drawn between the one-dimensional limit of the present analysis and the corresponding one-dimensional solution obtained by treating the dry region ahead of the wet front characterized by an exponentially decaying heat transfer coefficient.

Heat Transfer Analysis in an Automated Venetian Blind Window System

1989 ◽  
Vol 111 (1) ◽  
pp. 89-95 ◽  
Author(s):  
S. Rheault ◽  
E. Bilgen
Keyword(s):  
Heat Transfer ◽  
Indoor Air ◽  
Heat Transfer Analysis ◽  
System Of Nonlinear Equations ◽  
Governing Equations ◽  
Thermal Exchange ◽  
Window System ◽  
Materials Used ◽  
Heat Exchanges ◽  
Venetian Blind

The heat transfer through an automated venetian blind window system is theoretically studied. The assumptions for the solution of the problem were: Heat transfer is unidimensional, heat exchanges are at steady-state for the whole system, thermal exchange by convection over the blind is negligible, materials used are diffuse-gray surfaces, and radiative exchanges with the room walls are considered as if all the surfaces are blackbodies at indoor air temperature. The solution of the governing equations (system of nonlinear equations) is carried out by using an iterative numerical method. Summarized results are presented and compared to the case of a regular window in a typical Canadian climate during winter and summer seasons and with different louver angles. It is found that by using an automated blind system, the predicted auxiliary load can be reduced by up to 36 percent and 47 percent for winter and summer, respectively.

scholarly journals Statistics of Heat Transfer in Two-Dimensional Turbulent Rayleigh-Bénard Convection at Various Prandtl Number

Entropy ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 582 ◽  
Author(s):  
Hui Yang ◽  
Yikun Wei ◽  
Zuchao Zhu ◽  
Huashu Dou ◽  
Yuehong Qian
Keyword(s):  
Heat Transfer ◽  
Structure Function ◽  
Dissipation Rate ◽  
Large Scale ◽  
Thermal Dissipation ◽  
Small Scale ◽  
Linear Scaling ◽  
Two Dimensional ◽  
Large Scale Circulation ◽  
Rayleigh Benard

Statistics of heat transfer in two-dimensional (2D) turbulent Rayleigh-Bénard (RB) convection for Pr=6,20,100 and 106 are investigated using the lattice Boltzmann method (LBM). Our results reveal that the large scale circulation is gradually broken up into small scale structures plumes with the increase of Pr, the large scale circulation disappears with increasing Pr, and a great deal of smaller thermal plumes vertically rise and fall from the bottom to top walls. It is further indicated that vertical motion of various plumes gradually plays main role with increasing Pr. In addition, our analysis also shows that the thermal dissipation is distributed mainly in the position of high temperature gradient, the thermal dissipation rate εθ already increasingly plays a dominant position in the thermal transport, εu can have no effect with increase of Pr. The kinematic viscosity dissipation rate and the thermal dissipation rate gradually decrease with increasing Pr. The energy spectrum significantly decreases with the increase of Pr. A scope of linear scaling arises in the second order velocity structure functions, the temperature structure function and mixed structure function(temperature-velocity). The value of linear scaling and the 2nd-order velocity decrease with increasing Pr, which is qualitatively consistent with the theoretical predictions.

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