scholarly journals The numerical solution of the transient heat conduction problem using the lattice Boltzmann method

2012 ◽  
Vol 11 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Grazyna Kaluza ◽  
Keyword(s):  
Heat Conduction ◽  
Numerical Solution ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Heat Conduction Problem ◽  
Transient Heat Conduction ◽  
Transient Heat Conduction Problem ◽  
Boltzmann Method

scholarly journals Lattice Boltzmann method simulation of the gas heat conduction of nanoporous material

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3749-3756
Author(s):  
Ya Han ◽  
Shuai Li ◽  
Hai-Dong Liu ◽  
Weipeng Cui
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Lattice Boltzmann Method ◽  
Knudsen Number ◽  
Lattice Boltzmann ◽  
Size Effects ◽  
Temperature Jump ◽  
Boundary Scattering ◽  
Nanoporous Material ◽  
Boltzmann Method

In order to deeply investigate the gas heat conduction of nanoporous aerogel, a model of gas heat conduction was established based on microstructure of aerogel. Lattice Boltzmann method was used to simulate the temperature distribution and gas thermal conductivity at different size, and the size effects of gas heat conduction have had been obtained under micro-scale conditions. It can be concluded that the temperature jump on the boundary was not obvious and the thermal conductivity remained basically constant when the value of Knudsen number was less than 0.01; as the value of Knudsen number increased from 0.01 to 0.1, there was a clear temperature jump on the boundary and the thermal conductivity tended to decrease and the effect of boundary scattering increased drastically, as the value of Knudsen number was more than 0.1, the temperature jump increased significantly on the boundary, furtherly, the thermal conductivity decreased dramatically, and the size effects were significantly.

Application of numerical procedure for thermal diagnostics of the delamination of strengthening material at concrete construction

2019 ◽  
Vol 30 (5) ◽  
pp. 2655-2668 ◽  
Author(s):  
Wojciech Piotr Adamczyk ◽  
Marcin Gorski ◽  
Ziemowit Ostrowski ◽  
Ryszard Bialecki ◽  
Grzegorz Kruczek ◽  
...  
Keyword(s):  
Heat Conduction ◽  
Thermal Resistance ◽  
Quantitative Assessment ◽  
Heat Conduction Problem ◽  
Transient Heat Conduction ◽  
Decision Variable ◽  
Assessment Procedure ◽  
Ir Camera ◽  
Content Type ◽  
Transient Heat Conduction Problem

Purpose Large structural objects, primarily concrete bridges, can be reinforced by gluing to their stretched surface tapes of fiber-reinforced polymer (FRP). The condition for this technology to work requires the quality of the bonding of FRP and the concrete to be perfect. Possible defects may arise in the phase of construction but also as a result of long-term fatigue loads. These defects having different forms of voids and discontinuities in the bonding layer are difficult to detect by optical inspection. This paper aims to describe the development of a rapid and nondestructive method for quantitative assessment of the debonding between materials. Design/methodology/approach The applied technique belongs to the wide class of active infrared (IR) thermography, the principle of which is to heat (or cool) the investigated object, and determine the properties of interest from the recorded, by an IR camera, temperature field. The methodology implemented in this work is to uniformly heat for a few seconds, using a set of halogen lamps, the FRP surface attached to the concrete. The parameter of interest is the thermal resistance of the layer separating the polymer tape and the concrete. The presence of voids and debonding will result in large values of this resistance. Its value is retrieved by solving an inverse transient heat conduction problem. This is accomplished by minimizing, in the sense of least squares, the difference between the recorded and simulated temperatures. The latter is defined as a solution of a 1D transient heat conduction problem with the already mentioned thermal resistance treated as the only decision variable. Findings A general method has been developed, which detects debonding of the FRP tapes from the concrete. The method is rapid and nondestructive. Owing to a special selection of the compared dimensionless measured and simulated temperatures, the method is not sensitive to the surface quality (roughness and emissivity). Measurements and calculation may be executed within seconds. The efficiency of the technique has been shown at a sample, where the defects have been artificially introduced in a controlled manner. Originality/value A quantitative assessment procedure which can be used to determine the extent of the debonding has been developed. The procedure uses inverse technique whose result is the unknown thermal resistance between the member and the FRP strip.

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