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.

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.

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.

Effect of Metallic Coatings on the Thermal Contact Conductance of Turned Surfaces

1990 ◽  
Vol 112 (4) ◽  
pp. 864-871 ◽  
Author(s):  
T. K. Kang ◽  
G. P. Peterson ◽  
L. S. Fletcher
Keyword(s):  
Experimental Data ◽  
Thermal Contact ◽  
Coating Material ◽  
Thermal Contact Conductance ◽  
Enhancement Effect ◽  
Metallic Coatings ◽  
Coating Materials ◽  
Contact Conductance ◽  
Significant Parameter ◽  
Contact Pressures

An experimental investigation was conducted to determine the degree to which the thermal contact conductance at the interface of contacting Aluminum 6061 T6 surfaces could be enhanced through the use of vapor-deposited metallic coatings. Three different coating materials (lead, tin, and indium) were evaluated using four different thicknesses for each coating material. The results verified the existence of an optimum coating thickness, shown to be in the range of 2.0 to 3.0 μm for indium, 1.5 to 2.5 μm for lead, and 0.2 to 0.5 μm for tin. The enhancement factors for thermal contact conductance were found to be on the order of 700, 400, and 50 percent, respectively. Based upon the experimental data, the hardness of the coating materials appears to be the most significant parameter in ranking the substrate and coating material combinations; however, additional experimental data are needed to substantiate this hypothesis. Finally, it was apparent that the thermal contact conductance enhancement effect was greatest at low contact pressures and decreased significantly with increases in the contact pressure.

scholarly journals The effect of internal contact pressure on thermal contact conductance during coil cooling

2020 ◽  
Vol 50 ◽  
pp. 418-424 ◽  
Author(s):  
Joonas Ilmola ◽  
Aarne Pohjonen ◽  
Oskari Seppälä ◽  
Jari Larkiola
Keyword(s):  
Contact Pressure ◽  
Thermal Contact ◽  
Thermal Contact Conductance ◽  
Contact Conductance ◽  
Internal Contact
Sign in / Sign up

Export Citation Format

Share Document