Porous metal model for calculating slot thermal conductivity coefficient of electric machines

2017 ◽  
Vol 111 ◽  
pp. 981-988 ◽  
Author(s):  
Xiaomei Liu ◽  
Haitao Yu ◽  
Zhenchuan Shi ◽  
Lei Huang ◽  
Tao Xia ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Conductivity Coefficient ◽  
Porous Metal ◽  
Electric Machines

Theoretical Analysis on Heat Transfer Characteristics of Metal Rubber

2011 ◽  
Vol 183-185 ◽  
pp. 1696-1700
Author(s):  
Bin Zhu ◽  
Jie Hong ◽  
Yan Hong Ma
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Conductivity Coefficient ◽  
Heat Insulation ◽  
Engineering Application ◽  
Porous Metal ◽  
Transfer Model ◽  
Fourier Law ◽  
Theoretical Support ◽  
Metal Rubber

Based on the basic components of the porous Metal Rubber (MR) materials, all kinds of heat transfer modes were analyzed. Wire helix was considered as the micro-element of Metal Rubber by analyzing the characteristics of processing components of Metal Rubber. According to the acoustoelectric analogy method, the heat transfer model of MR was established on the basis of arrangement of wire helix and Fourier Law. The formula of thermal conductivity coefficient was derived. And the LFA 427 instrument was used to obtain thermal conductivity characteristics of MR experimentally. The results showed that the model had certain application. This model was valuable for the analysis of the thermal properties and the design of Metal Rubber. It provided theoretical support for the further engineering application of Metal Rubber in the field of heat insulation.

The effect of variable properties and rotation in a visco-thermoelastic orthotropic annular cylinder under the Moore–Gibson–Thompson heat conduction model

2021 ◽  
pp. 146442072098589
Author(s):  
Ahmed E Aboueregal ◽  
Hamid M Sedighi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stresses ◽  
Thermal Conductivity Coefficient ◽  
Variable Properties ◽  
Transformation Technique ◽  
Present Contribution ◽  
Conduction Model ◽  
Thermoelastic Model ◽  
Shock Heating ◽  
Physical Fields

The present contribution aims to address a problem of thermoviscoelasticity for the analysis of the transition temperature and thermal stresses in an infinitely circular annular cylinder. The inner surface is traction-free and subjected to thermal shock heating, while the outer surface is thermally insulated and free of traction. In this work, in contrast to the various problems in which the thermal conductivity coefficient is considered to be fixed, this parameter is assumed to be variable depending on the temperature change. The problem is studied by presenting a new generalized thermoelastic model of thermal conductivity described by the Moore–Gibson–Thompson equation. The new model can be constructed by incorporating the relaxation time thermal model with the Green–Naghdi type III model. The Laplace transformation technique is used to obtain the exact expressions for the radial displacement, temperature and the distributions of thermal stresses. The effects of angular velocity, viscous parameter, and variance in thermal properties are also displayed to explain the comparisons of the physical fields.

scholarly journals INFLUENCE OF LIGHTWEIGHT FILLERS ON THE PERFORMANCE OF CEMENT-BASED SKIM COAT

2020 ◽  
Vol 12 (1) ◽  
pp. 5-11
Author(s):  
MARCIN KUPIŃSKI ◽  
KAROLINA STOBIENIECKA ◽  
KAROL SKOWERA
Keyword(s):  
Thermal Conductivity ◽  
Thermal Conductivity Coefficient ◽  
Pozzolanic Reaction ◽  
Vapor Condensation ◽  
Cement Matrix ◽  
Capillary Absorption ◽  
Mold Growth ◽  
Expanded Perlite ◽  
Water Vapor Condensation ◽  
Effective Additive

Lightweight fillers are used in dry-mixed building mortars in order to improve thermal insulation properties, yield, and workability. In the case of thin layer products, used as a finishing layer, reduced thermal conductivity coefficient enables to restrain of water vapor condensation on walls – which inhibits mold growth. The aim of the study was to determine the influence of 4 types of lightweight fillers on the performance of cement-based skim coat – with emphasis on the economic aspect. Formulas reflecting typical commercial products were used. The dosage of different components -such as expanded perlite, glass and polymeric bubbles or expanded glass – was optimized for sufficient yield and workability, keeping the constant price of 1 kg of the final product. Mechanical parameters, capillary absorption coefficient, and thermal conductivity coefficient were determined. Observations by Scanning Electron Microscope revealed poor incorporation of polymer microspheres in the cement matrix, leading to loss of mechanical strength. With the addition of expanded glass, an increase of flexural and compressive strength thanks to the pozzolanic reaction was observed. Glass bubbles were found the most effective additive.

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