A model of thermal contact conductance at high real contact area fractions

Wear ◽  
2010 ◽  
Vol 268 (1-2) ◽  
pp. 77-85 ◽  
Author(s):  
Przemysław Sadowski ◽  
Stanisław Stupkiewicz
Keyword(s):  
Contact Area ◽  
Thermal Contact ◽  
Thermal Contact Conductance ◽  
Real Contact Area ◽  
Contact Conductance ◽  
Real Contact

FEA-Based Numerical Simulation and Theoretical Modeling for Predicting Thermal Contact Conductance

2018 ◽  
pp. 118-139
Author(s):  
Sachin Rana
Keyword(s):  
Surface Roughness ◽  
Contact Area ◽  
Loading Condition ◽  
Thermal Contact ◽  
Thermal Contact Conductance ◽  
Real Contact Area ◽  
Fem Model ◽  
Contact Conductance ◽  
Real Contact ◽  
Fine Mesh

The chapter states the problem of thermal contact conductance between surfaces. Rough surface generation and thermal contact conductance has been simulated using Finite Element Method (FEM) based Ansys. The resulting geometry is meshed by different meshing method to convert the solid model into FEM model. The main aim of meshing is to create fine and coarse mesh at the contact to reduce the computational time. To create a fine mesh at contact free meshing with refinement and mapped mesh has been used. The analysis has been performed on the FEM model with varying loading condition of different surface roughness and different materials to get the real contact area and thus thermal contact conductance. The variation of thermal contact conductance and real contact area with pressure of different surface roughness and with surface roughness of different loading condition of the specimen made of aluminum and mild steel has been plotted and compared.

Thermal Contact Resistance at a Metal Foam-Solid Surface Interface

2011 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Scott Hsieh ◽  
Majid Bahrami
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Effective Thermal Conductivity ◽  
Contact Area ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Metal Foams ◽  
Real Contact Area ◽  
The Real ◽  
Real Contact

Accurate information on heat transfer and temperature distribution in metal foams is necessary for design and modeling of thermal-hydraulic systems incorporating metal foams. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance (TCR) associated with the interface between the metal foams and adjacent surfaces/layers. In the present study, a test bed that allows the separation of effective thermal conductivity and thermal contact resistance in metal foams is described. Measurements are performed in a vacuum under varying compressive loads using ERG Duocel aluminum foam samples with different porosities and pore densities. Also, a graphical method associated with a computer code is developed to demonstrate the distribution of contact spots and estimate the real contact area at the interface. Our results show that the porosity and the effective thermal conductivity remain unchanged with the variation of compression in the range of 0 to 2 MPa; but TCR decreases significantly with pressure due to an increase in the real contact area at the interface. Moreover, the ratio of real to nominal contact area varies between 0 to 0.013, depending upon the compressive force, porosity, and surface characteristics.

Analytical Studies of Contact of Nominally Flat Surfaces; Effect of Previous Loading

1971 ◽  
Vol 93 (4) ◽  
pp. 451-456 ◽  
Author(s):  
B. Mikic
Keyword(s):  
Size Distribution ◽  
Contact Area ◽  
Thermal Contact ◽  
Thermal Contact Conductance ◽  
Contact Conductance ◽  
Flat Surfaces ◽  
Analytical Studies ◽  
Previous Loading

This work analytically investigates effect of previous loading on contact area, number of contact prints, their size distribution, and the value of thermal contact conductance for two nominally flat surfaces in contact. The model used in the analysis assumes that the surfaces are Gaussian and that in the first loading deformation of the surface asperities is plastic.

A three-dimensional fractal theory based on thermal contact conductance model of rough surfaces

2017 ◽  
Vol 232 (5) ◽  
pp. 528-539 ◽  
Author(s):  
Yongsheng Zhao ◽  
Cui Fang ◽  
Ligang Cai ◽  
Zhifeng Liu
Keyword(s):  
Rough Surfaces ◽  
Fractal Theory ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Thermal Conductance ◽  
Engineering Application ◽  
Thermal Contact Conductance ◽  
Real Contact Area ◽  
Contact Conductance ◽  
Elastic Plastic

The thermal contact conductance is an important problem in the field of heat transfer. In this research, a three-dimensional fractal theory based on the thermal contact conductance model is presented. The topography of the contact surfaces was fractal featured and determined by fractal parameters. The asperities in the microscale were considered as elastic, elastic-plastic, or plastic deformations. The real contact area of the asperities could be obtained based on the Hertz contact theory. It was assumed that the rough contact surface was composed of numerous discrete and parallel microcontact cylinders. Consequently, the thermal contact conductance of the surface roughness was composed of the thermal constriction conductance of microcontacts and the air medium thermal conductance of microgaps. The thermal contact conductance of rough surfaces could be calculated by the microasperities integration. An experimental set-up with annular interface was designed to verify the presented thermal contact conductance model. Three materials were used for the thermal contact conductance analysis with different fractal dimensions D and fractal roughness parameters G. The numerical results demonstrated that the thermal contact conductance could be affected by the elastic-plastic deformation of the asperities and the gap thermal conductance should not be ignored under the lower contact load. The presented model would provide a theoretical basis for thermal transfer engineering application.

An FFT Deterministic Simulation of Elastic Rough Surfaces in Three-Dimensional Contact and Model Analysis

2009 ◽  
Author(s):  
Robert L. Jackson ◽  
Itzhak Green
Keyword(s):  
Contact Area ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Real Contact Area ◽  
Real Contact ◽  
Contact Models ◽  
Surface Profiles ◽  
Rough Surface Contact ◽  
Mathematical Foundations

For practicing engineers in industry it is important to have closed-form, easy to use equations that can be used to predict the real contact area, and relate it to friction, wear, adhesion, and electrical and thermal contact resistance. There are quite a few such models in the literature, but their agreement or their effectiveness has not been determined. This work will use several measured surface profiles to make predictions of contact area and contact force from many elastic contact models and compare them to a deterministic FFT based rough surface contact model. The results show that several of the models show good quantitative and qualitative agreement despite having very different mathematical foundations.

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