Prediction of Thermal Contact Conductance by Surface Deformation Analysis

Mapping Intimacies ◽

10.1115/imece2001/htd-24376 ◽

2001 ◽

Author(s):

Vishal Singhal ◽

Suresh V. Garimella

Keyword(s):

Surface Deformation ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Deformation Analysis ◽

Improved Method ◽

Contact Conductance ◽

The Real ◽

Real Area Of Contact ◽

Surface Profiles ◽

Real Area

Abstract An improved method has been developed for the prediction of thermal contact conductance between two nominally flat metallic rough surfaces by analysis of the deformation of individual asperities in contact. The deformation of the asperities in contact has been taken into account by considering three different modes of deformation — elastic, elastic-plastic and plastic. The model uses an iterative procedure to determine the real area of contact between the deformed surfaces for a given load, nominal area of contact, surface profiles and material properties of the surfaces in contact. The contact conductance is then determined as a function of the ratio of the real area of contact to the apparent area of contact The predicted variation of contact conductance with load obtained from the model is compared to simplified analytical predictions in the literature as well as to experiments conducted as part of this work.

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A New Three-Dimensional Numerical Model of Rough Contact: Influence of Mode of Surface Deformation on Real Area of Contact and Pressure Distribution

Journal of Tribology ◽

10.1115/1.4028286 ◽

2014 ◽

Vol 137 (1) ◽

Cited By ~ 16

Author(s):

A. Jourani

Keyword(s):

Pressure Distribution ◽

Pressure Field ◽

Surface Deformation ◽

Three Dimensional ◽

Real Contact Area ◽

Geometrical Approach ◽

Deterministic Models ◽

The Real ◽

Real Area Of Contact ◽

Real Area

Surface roughness causes contact to occur only at discrete spots called microcontacts. In the deterministic models real area of contact and pressure field are widely evaluated using Flamant and Boussinesq equations for two-dimensional (2D) and three-dimensional (3D), respectively. In this paper, a new 3D geometrical contact approach is developed. It models the roughness by cones and uses the concept of representative strain at each asperity. To discuss the validity of this model, a numerical solution is introduced by using the spectral method and another 3D geometrical approach which models the roughness by spheres. The real area of contact and the pressure field given by these approaches show that the conical model is almost insensitive to the degree of isotropy of the rough surfaces, which is not the case for the spherical model that is only valid for quasi-isotropic surfaces. The comparison between elastic and elastoplastic models reveals that for a surface with a low roughness, the elastic approach is sufficient to model the rough contact. However, for surfaces having a great roughness, the elastoplastic approach is more appropriate to determine the real area of contact and pressure distribution. The results of this study show also that the roughness scale modifies the real contact area and pressure distribution. The surfaces characterized by high frequencies are less resistant in contact and present the lowest real area of contact and the most important mean pressure.

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The Use of Analog Computers for Determining Surface Parameters Required for Prediction of Thermal Contact Conductance

Journal of Heat Transfer ◽

10.1115/1.3688742 ◽

1964 ◽

Vol 86 (4) ◽

pp. 543-550 ◽

Cited By ~ 12

Author(s):

J. J. Henry ◽

H. Fenech

Keyword(s):

Experimental Data ◽

Unit Area ◽

Thermal Contact ◽

Analog Computer ◽

General Purpose ◽

Thermal Contact Conductance ◽

Average Thickness ◽

Contact Interface ◽

Contact Conductance ◽

Surface Profiles

The mathematical analysis of a thermal contact by Fenech and Rohsenow requires knowledge of certain parameters describing the geometry of the contact interface. These parameters are volume average thickness of the void above and below the plane of the contact, the number of contacts per unit area, and the ratio of the actual contact area to the total area. The authors outline a method for determining these parameters graphically. This paper describes a method for obtaining analog voltages of surface profiles of contacting surfaces and the application of a general purpose analog computer to determine the geometric parameters of contact as a function of contact pressure. The results of applying this method are combined with the analysis of Fenech and Rohsenow. The predicted contact conductance is found to agree well with experimental data at mean contact temperatures of 100, 200, and 300 F for load pressures of 100 to 20,000 psi.

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