Thermal contact resistance (TCR)/thermal contact conductance (TCC)

Interfacial thermal contact resistance between the impinging flow of a molten droplet and a substrate, which is qualified by thermal contact conductance, plays an important role in the spreading and solidification of a droplet. In the present study, a simple correlation for the thermal contact conductance in the rapid contact solidification process was developed. With this correlation being directly used in numerical simulation, for the first time, a variable thermal contact resistance was taken into consideration to simulate both the dynamics and phase change responses during a molten droplet impingement. Numerical results were compared with that of the cases when thermal contact resistance was zero or a constant. The changes in spread factor with time and thermal contact conductance indicated that predictions from the computer simulation were sensitive to the values of thermal contact resistance. Experiment was conducted to demonstrate the validity of the present study. Comparison results showed that rather than using a constant average value, better agreement between the experimental and numerical results would be obtained if a variable thermal contact resistance were used in the numerical simulation.

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On the Enhancement of the Thermal Contact Conductance: Effect of Loading History

Journal of Heat Transfer ◽

10.1115/1.521436 ◽

1999 ◽

Vol 122 (1) ◽

pp. 46-49 ◽

Cited By ~ 22

Author(s):

Y. Z. Li ◽

C. V. Madhusudana ◽

E. Leonardi

Keyword(s):

Heat Flow ◽

Contact Resistance ◽

Experimental Work ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Cost Effective ◽

Thermal Contact Conductance ◽

Loading History ◽

Contact Conductance ◽

Resistance To Heat

A resistance to heat flow exists at the junction of two surfaces. It has long been recognized that there exists a hysteresis effect, that is, the value of thermal contact resistance in the unloading process is less than that in the loading process at the same load. However, little work has been done in utilizing this phenomenon to enhance the thermal contact conductance. The present experimental work investigated the effect of loading history; in particular the number of load cycles and overloading pressure, on the thermal contact conductance. It was found that the value of the thermal contact conductance might be enhanced by up to 51 percent. A cost-effective way of enhancing the contact conductance is suggested. [S0022-1481(00)01601-7]

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Tuning thermal contact conductance at graphene–copper interfaceviasurface nanoengineering

Nanoscale ◽

10.1039/c5nr00564g ◽

2015 ◽

Vol 7 (14) ◽

pp. 6286-6294 ◽

Cited By ~ 49

Author(s):

Yang Hong ◽

Lei Li ◽

Xiao Cheng Zeng ◽

Jingchao Zhang

Keyword(s):

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Contact Conductance

By introducing a surface nanoengineering design at sub-nm level, the thermal contact resistance between graphene and copper is reduced by 17% due to enhanced phonon couplings across the interface.

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Thermal Contact Resistance Modeling of Non-Flat, Roughened Surfaces With Non-Metallic Coatings

Journal of Heat Transfer ◽

10.1115/1.1338135 ◽

2000 ◽

Vol 123 (1) ◽

pp. 11-23 ◽

Cited By ~ 14

Author(s):

E. E. Marotta ◽

L. S. Fletcher ◽

Thomas A. Dietz

Keyword(s):

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Metallic Coatings ◽

Thermomechanical Model ◽

Contact Conductance ◽

Flat Surfaces ◽

Resistance Modeling ◽

Aluminum Substrates

Essentially all models for prediction of thermal contact conductance or thermal contact resistance have assumed optically flat surfaces for simplification. A few thermal constriction models have been developed which incorporate uncoated, optically non-flat surfaces based on the bulk mechanical properties of the material. Investigations have also been conducted which incorporate the thermophysical properties of metallic coatings and their effective surface microhardness to predict the overall thermal contact conductance. However, these studies and subsequent models have also assumed optically flat surfaces; thus, the application of these models to optically non-flat, coated surface conditions is not feasible without modifications. The present investigation develops a thermomechanical model that combines both microscopic and macroscopic thermal resistances for non-flat, roughened, surfaces with non-metallic coatings. The thermomechanical model developed as a result of this study predicts the thermal contact resistance of several non-metallic coatings deposited on metallic aluminum substrates quite well.

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Measuring the Thermal Contact Resistance of a Junction by T Type Probe Method

ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer, Volume 2 ◽

10.1115/mnhmt2009-18293 ◽

2009 ◽

Author(s):

Jianli Wang ◽

Ming Gu ◽

Xing Zhang

Keyword(s):

Carbon Fiber ◽

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

High Vacuum ◽

Thermal Effusivity ◽

Metallic Powder ◽

Thermal Contact Conductance ◽

Hot Wire ◽

Dry Contact

Using a T type probe, the effect of the interstitial material (interposer) on the thermal contact resistance of a junction has been estimated by measuring an individual carbon fiber with different interposers, including the solidified metallic powder, lubricant grease, and dry contact as a comparison. For the metallic powder, the thermal contact conductance was obtained to be 3.0 M W m−2 K−1 by changing the fiber length when the same contact between the fiber and the hot wire was maintained. However, this method can only be applicable to the solidified contact, and the stability of the operating temperature is a must in each length measurement. To estimate the thermal contact resistance of the lubricant Apiezon N grease, even a dry contact, an improved T type probe was employed, by applying an alternative current to the hot wire. This method was verified by measuring the same type of carbon fiber in the frequency range of 0.1 to 1Hz based on a Labview-based virtual lock-in measurement system. The same value of the thermal effusivity of the test fiber was obtained with different interposers, and the thermal contact conductances for the dry contact and high vacuum grease were found to be 0.10 M W m−2 K−1 and 0.26 M W m−2 K−1, respectively.

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Measurement of the Thermophysical Properties of Anisotropic Insulation Materials with Consideration of the Effect of Thermal Contact Resistance

Materials ◽

10.3390/ma13061353 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1353 ◽

Cited By ~ 2

Author(s):

Dongxu Han ◽

Kai Yue ◽

Liang Cheng ◽

Xuri Yang ◽

Xinxin Zhang

Keyword(s):

Thermal Conductivity ◽

Thermal Resistance ◽

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Maximum Deviation ◽

Insulation Materials ◽

Steady State Method ◽

Different Temperatures

A novel method involving the effect of thermal contact resistance (TCR) was proposed using a plane heat source smaller than the measured samples for improving measurement accuracy of the simultaneous determination of in-plane and cross-plane thermal conductivities and the volumetric heat capacity of anisotropic materials. The heat transfer during the measurement process was mathematically modeled in a 3D Cartesian coordinate system. The temperature distribution inside the sample was analytically derived by applying Laplace transform and the variables separation method. A multiparameter estimation algorithm was developed on the basis of the sensitivity analysis of the parameters to simultaneously estimate the measured parameters. The correctness of the algorithm was verified by performing simulation experiments. The thermophysical parameters of insulating materials were experimentally measured using the proposed method at different temperatures and pressures. Fiber glass and ceramic insulation materials were tested at room temperature. The measured results showed that the relative error was 1.6% less than the standard value and proved the accuracy of the proposed method. The TCRs measured at different pressures were compared with those obtained using the steady-state method, and the maximum deviation was 8.5%. The thermal conductivity obtained with the contact thermal resistance was smaller than that without the thermal resistance. The measurement results for the anisotropic silica aerogels at different temperatures and pressures revealed that the thermal conductivity and thermal contact conductance increased as temperature and pressure increased.

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Three-Dimensional Thermal Model of Resistance Spot Welding in Aluminum

10.1115/imece1999-1094 ◽

1999 ◽

Author(s):

A. A. S. Arefin Kabir ◽

Jamil A. Khan ◽

Kirk Broach

Keyword(s):

Contact Resistance ◽

Phase Change ◽

Weld Pool ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Work Piece ◽

Contact Conductance ◽

Faying Surface ◽

Surface Contact ◽

Surface Contact Resistance

Abstract A 3-D thermal model for resistance spot welding in aluminum is presented. The numerical model, validated with experimental findings, considers phase change and the associated weld-pool convection. A parametric study is performed to determine the influence of welding features such as faying surface (work-piece contact surface) contact resistance, current, electrode-work-piece surface-thermal-contact-conductance and electrode tip diameter. These parameters have significant effects on the nugget and heat-affected-zone geometry. The phase change morphology, including melting and solidification rates and weld pool dynamics, is also significantly influenced by the parameters studied. The strongest convection was observed at the center of the molten pool in a plane aligned with gravity. Although two prominent convection cells develop, the phase change morphology is not significantly affected due to the short welding time (less than 0.05 seconds) and low fluid velocity (smaller than 1 × 10−2 mm/s). The nugget grows nonlinearly with increasing current and faying surface contact resistance while diminishing with increasing electrode work-piece surface-thermal-contact-conductance. The influence of faying surface contact resistance on nugget size is less than that of the other parameters. Optimum selection of electrode tip diameter provides the best possible nugget. The duration of weld pool existence increases with the increasing current but decreases with the increasing electrode work-piece surface-thermal-contact-conductance.

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