scholarly journals Analysis of Heat Transfer in the Structures with Regularly Arranged Gas Cavities

2008 ◽  
Vol 45 (4) ◽  
pp. 14-24 ◽  
Author(s):  
D. Cepīte ◽  
A. Jakovičs
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Conduction ◽  
Building Materials ◽  
Material Structure ◽  
Radiation Heat ◽  
Parallel Orientation ◽  
Transfer Processes ◽  
Radiation Heat Exchange

Analysis of Heat Transfer in the Structures with Regularly Arranged Gas CavitiesIn the work, the effective thermal conductivity (ETC) of anisotropic composite material (well-conducting media with regular cavities of the air) is studied by numerical modelling. The authors examine the influence of orientation and size of the cavities on the ETC of material structure and the role of thermal conduction, convection and radiation in the heat transfer processes. For modelling,Keratermtype material was chosen. It has been proved numerically that the ETC of similar structures is lower in the case when the cavities are oriented perpendicularly to the heat flux direction as compared with parallel orientation. According to the analysis performed, the radiation heat exchange in such cavities dominates over the convective heat transfer in the observed temperature range. In the calculations of ETC in structures of the kind, convection inside the cavities can be omitted. The proposed approach allows optimisation of the arrangement and size of the cavities in similar building materials.

scholarly journals Design and Implementation of a Laboratory Equipment for Studying Heat Transfer by Conduction

2019 ◽  
Vol 11 (1) ◽  
pp. 153-156
Author(s):  
István Padrah ◽  
Judit Pásztor ◽  
Rudolf Farmos
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Conduction ◽  
Thermal Conduction ◽  
Transfer Mechanism ◽  
Measuring Instrument ◽  
Heat Transfer Mechanism ◽  
Laboratory Equipment ◽  
Insulating Materials ◽  
Design And Implementation

Abstract Thermal conduction is a heat transfer mechanism. It is present in our everyday lives. Studying thermal conductivity helps us better understand the phenomenon of heat conduction. The goal of this paper is to measure the thermal conductivity of various materials and compare results with the values provided by the manufacturers. To achieve this we assembled a measuring instrument and performed measurements on heat insulating materials.

Increasing heat transfer performance of thermoplastic polyurethane by constructing thermal conduction channels of ultra-thin boron nitride nanosheets and carbon nanotubes

2020 ◽  
Vol 44 (43) ◽  
pp. 18823-18830
Author(s):  
Yue Ruan ◽  
Nian Li ◽  
Cui Liu ◽  
Liqing Chen ◽  
Shudong Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Thermal Conduction ◽  
Heat Transfer Performance ◽  
Thermoplastic Polyurethane ◽  
Transfer Performance ◽  
Boron Nitride Nanosheets ◽  
Thermally Conductive

The TPU-based thermally conductive composite reaches a thermal conductivity of 1.35 W m−1 K−1 and increases the tensile strength by at least 300%.

scholarly journals THE ACTIVE METHOD OF CONTROL THE THERMAL CONDUCTIVITY OF BUILDING MATERIALS AND PRODUCTS

2019 ◽  
Vol 4 (7) ◽  
pp. 57-62
Author(s):  
Д. Карпов ◽  
Denis Karpov
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Test Object ◽  
Building Materials ◽  
Thermal Control ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Transfer Resistance ◽  
Non Destructive ◽  
Controlled Object

Thermal control refers to non-destructive testing methods. There are passive and active thermal non-destructive testing. With passive thermal control, the test object is characterized by a temperature field formed during its operation. With active thermal control, an additional source of thermal stimulation of the controlled object is used. Thermal control is widely used in various sectors of construction, energy, engineering and transport. The paper proposes a variant of active thermal non-destructive control of thermal conductivity coefficient of building materials and products on the example of a fragment of a building structure made of silicate bricks. The controlled object is subjected to thermal stimulation by an external source of thermal energy until the fixed thermal regime. Thermography of the test object surfaces is performed. The average values of surfaces temperature or individual sections of controlled object are calculated. The heat equation determines a controlled parameter - the heat coefficient of the object under control. The thermal resistance (heat transfer resistance) of the controlled object is calculated with a known coefficient of thermal conductivity. The heat transfer coefficient is calculated with a known coefficient of thermal resistance (heat transfer resistance). The method is implemented in the laboratory. It can be used in field and operating conditions for accurate and rapid determination of the key thermal properties of building materials and products.

scholarly journals The Role of the Plumage in Heat Transfer Processes of Birds

2000 ◽  
Vol 40 (4) ◽  
pp. 575-584 ◽  
Author(s):  
Blair O. Wolf ◽  
Glenn E. Walsberg
Keyword(s):  
Heat Transfer ◽  
Transfer Processes
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