The Thermal Conductance of Indium-Filled Contacts at Cryogenic Temperatures

2004 ◽  
Author(s):  
Patrick E. Phelan ◽  
Meng Zhang
Keyword(s):  
Contact Pressure ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Contact Conductance ◽  
Experimental Measurements ◽  
Cryogenic Temperatures ◽  
Indium Foil ◽  
Copper Surfaces ◽  
Contact Pressures ◽  
Average Sample

Indium foil is often used to increase the thermal contact conductance hc of junctions at cryogenic temperatures, yet relatively few experimental data on hc at subambient temperatures are available. Here, experimental measurements of hc at a copper/copper junction containing a 25.4-μm-thick indium foil are reported. The average sample temperature ranged from 40 to 180 K, and the contact pressures ranged from 0.2 to 20 MPa. Although it was originally anticipated that increasing the contact pressure would lead to increasing hc, the observed hc showed little or no dependence on contact pressure. This was attributed to the severe nonflatness of the copper surfaces. Comparison between the measured hc, and that calculated from existing “flat” and “nonflat” theories indicated better agreement with the “nonflat” model, although the model still predicted that hc should depend on pressure.

Influence of Contact Pressure on the Thermal Contact Conductance of Layered AA3003 Aluminium

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Contact Pressure ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Contact Conductance ◽  
Contact Conductance ◽  
Interface Thermal Resistance ◽  
Measurement Results ◽  
Semi Empirical ◽  
The Relationship

For the optimization of the annealing process of aluminium coils, simulation of the process is often performed. To simulate the process with higher accuracy, reliable input parameters are required and the thermal conductivity (thermal contact conductance) is one of them. In the present study, the thermal conductivity and thermal contact conductance of AA3003 alloy sheets were measured by a steady state comparative longitudinal heat flow method at different contact pressure. To evaluate the thermal conductance at the interface, thermal resistance network model' was applied. In addition, the surface roughness of the sheets was also investigated. Based on the measurement results, the semi-empirical equation for the relationship between thermal contact conductance and contact pressure was obtained

Thermal Contact Conductance Across Gold-Coated OFHC Copper Contacts in Different Media

2005 ◽  
Vol 127 (6) ◽  
pp. 657-659 ◽  
Author(s):  
Bapurao Kshirsagar, ◽  
Prashant Misra, ◽  
Nagaraju Jampana, and ◽  
M. V. Krishna Murthy
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Contact Pressure ◽  
Thermal Contact ◽  
High Conductivity ◽  
Thermal Contact Conductance ◽  
Ofhc Copper ◽  
Contact Conductance ◽  
Contact Pressures ◽  
Good Agreement

The thermal contact conductance studies across gold-coated oxygen-free high-conductivity copper contacts have been conducted at different contact pressures in vacuum, nitrogen, and helium environments. It is observed that the thermal contact conductance increases not only with the increase in contact pressure but also with the increase in thermal conductivity of interstitial medium. The experimental data are found to be in good agreement with the literature.

An Experimental Study to Show the Effect of Thermal Stress on Thermal Contact Conductance at Sub-megapascal Contact Pressures

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Prashant Misra ◽  
J. Nagaraju
Keyword(s):  
Thermal Stress ◽  
Contact Pressure ◽  
Thermal Stresses ◽  
Thermal Contact ◽  
Experimental Studies ◽  
Thermal Contact Conductance ◽  
Large Temperature ◽  
Contact Conductance ◽  
Closed Contact ◽  
Contact Pressures

Experimental studies are presented to show the effect of thermal stresses on thermal contact conductance (TCC) at low contact pressures. It is observed that in a closed contact assembly, contact pressure acting on the interface changes with the changing temperature of contact members. This change in contact pressure consequently causes variations in the TCC of the junction. A relationship between temperature change and the corresponding magnitude of developed thermal stress in a contact assembly is determined experimentally. Inclusion of a term called temperature dependent load correction factor is suggested in the theoretical model for TCC to make it capable of predicting TCC values more accurately in contact assemblies that experience large temperature fluctuations.

Heat Conduction Through a Layered Pressure Vessel Wall

1986 ◽  
Vol 108 (4) ◽  
pp. 418-422
Author(s):  
M. Ueda ◽  
M. Kinugawa ◽  
Y. Hara ◽  
K. Yamazato
Keyword(s):  
Heat Conduction ◽  
Pressure Vessel ◽  
Vessel Wall ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Postweld Heat Treatment ◽  
Pressure Vessels ◽  
Scale Model ◽  
Thermal Contact Conductance ◽  
Simplified Method

Heat conduction tests of a layered pressure vessel wall were performed using full-scale model pressure vessel courses. Thermal conductance between layers was estimated from the test results. A simplified method, developed for the thermal analysis of layered-wall pressure vessels during postweld heat treatment and actual operation, includes thermal contact conductance at the layer interfaces which depends upon the contact pressure and gap height. Temperature changes calculated using the simplified method agreed well with the experiments.

scholarly journals Demonstration of a Compliant Micro-Spring Array As a Thermal Interface Material for Pluggable Optoelectronic Transceiver Modules

2019 ◽  
Author(s):  
Jin Cui ◽  
Liang Pan ◽  
Justin A. Weibel
Keyword(s):  
Heat Sink ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Interface Material ◽  
Thermal Contact Conductance ◽  
Compression Pressure ◽  
Thermal Interface ◽  
Operation Temperature ◽  
Optical Module ◽  
Dry Contact

Abstract Pluggable optoelectronic transceiver modules are widely used in the fiber-optic communication infrastructure. It is essential to mitigate thermal contact resistance between the high-power optical module and its riding heat sink in order to maintain the required operation temperature. The pluggable nature of the modules requires dry contact thermal interfaces that permit repeated insertion–disconnect cycles under low compression pressures (∼10–100 kPa). Conventional wet thermal interface materials (TIM), such as greases, or those that require high compression pressures, are not suitable for pluggable operation. Here we demonstrate the use of compliant micro-structured TIM to enhance the thermal contact conductance between an optical module and its riding heat sink under a low compression pressure (20 kPa). The metallized and polymer-coated structures are able to accommodate the surface nonflatness and microscale roughness of the mating surface while maintaining a high effective thermal conductance across the thickness. This dry contact TIM is demonstrated to maintain reliable thermal performance after 100 plug-in and plug-out cycles while under compression.

Study on evaluation method of tube—fin thermal contact conductance

2010 ◽  
Vol 225 (2) ◽  
pp. 390-396
Author(s):  
D Tang ◽  
D Li ◽  
Y Peng ◽  
Z Du
Keyword(s):  
Contact Pressure ◽  
Evaluation Method ◽  
Thermal Contact ◽  
Element Model ◽  
Thermal Contact Conductance ◽  
Forming Process ◽  
Contact Conductance ◽  
Die Geometry ◽  
Novel Method ◽  
Tube Expansion

The thermal contact conductance (TCC) is one of the principal parameter in heat transfer mechanism of tube—fin heat exchangers. Because of the difficulties in experimental measurements, the tube—fin TCC has not been focused deeply. This article presents a novel method in evaluating the TCC of tube—fin heatexchanger. First, the tube—fin contact status is investigated with a finite-element model of tube expansion process. Distribution of contact pressure along the tube—fin interface is obtained from the simulation results. Then, experiments are carried out for the relationship between the contact pressure and the TCC. Combining the experiment result with the contact pressure distribution, the tube—fin TCC can be evaluated. Based on the method, effect of processing factors of the expansion forming process, such as expanding ratio and die geometry, are examined.

Influence of Temperature Distribution on Tighten Force in Tie-Bolt Fastened Rotor With Considering Thermal Contact Conductance

2015 ◽  
Author(s):  
He Peng ◽  
Ning Xu ◽  
Zhansheng Liu
Keyword(s):  
Surface Roughness ◽  
Thermal Expansion ◽  
Temperature Distribution ◽  
Contact Pressure ◽  
Thermal Contact ◽  
Thermal Contact Conductance ◽  
Axial Position ◽  
Contact Conductance ◽  
Pressure Surface ◽  
Axial Temperature

Tighten force has much influence on tie-bolt fastened rotor dynamics. Temperature distribution in tie-bolt fastened rotor results in thermal expansion of rotor and rods. The difference of thermal expansion between rotor and rods causes the variation of bolt load. With considering the thermal contact conductance, the thermal model of tie-bolt fastened rotor was established by finite element method and the axial temperature distribution was obtained. The influences of surface roughness, nominal contact pressure and axial position of contact on axial temperature distribution were analysed. Based on temperature distribution in the tie-bolt fastened rotor, the variation of tighten force was investigated. Results show that nominal contact pressure, surface roughness and axial contact arrange have different influences on the variation of tighten force with temperature.

Recent Developments in Contact Conductance Heat Transfer

1988 ◽  
Vol 110 (4b) ◽  
pp. 1059-1070 ◽  
Author(s):  
L. S. Fletcher
Keyword(s):  
Heat Transfer ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Contact Conductance ◽  
Contact Conductance ◽  
Thermal Rectification ◽  
Numerical Studies ◽  
Wide Range ◽  
Theoretical Investigations ◽  
Recent Developments

The characteristics of thermal contact conductance are increasingly important in a wide range of technologies. As a consequence, the number of experimental and theoretical investigations of contact conductance has increased. This paper reviews and categorizes recent developments in contact conductance heat transfer. Among the topics included are the theoretical/analytical/numerical studies of contact conductance for conforming surfaces and other surface geometries; the thermal conductance in such technological areas as advanced or modern materials, microelectronics, and biomedicine; and selected topics including thermal rectification, gas conductance, cylindrical contacts, periodic and sliding contacts, and conductance measurements. The paper concludes with recommendations for emerging and continuing areas of investigation.

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.

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