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

2000 ◽  
Vol 123 (1) ◽  
pp. 11-23 ◽  
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.

Deformation and Solidification of Droplet Impact With Variable Thermal Contact Resistance

2003 ◽  
Author(s):  
W. Wang ◽  
H.-H. Qiu ◽  
P. Cheng
Keyword(s):  
Numerical Simulation ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Solidification Process ◽  
Numerical Results ◽  
Thermal Contact Conductance ◽  
Contact Conductance ◽  
Molten Droplet ◽  
Comparison Results

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.

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

1999 ◽  
Vol 122 (1) ◽  
pp. 46-49 ◽  
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]

scholarly journals Tuning thermal contact conductance at graphene–copper interfaceviasurface nanoengineering

Nanoscale ◽  
2015 ◽  
Vol 7 (14) ◽  
pp. 6286-6294 ◽  
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.

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

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.

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

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1353 ◽  
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.

Thermal Contact Conductance of Packed Beds in Contact With a Flat Surface

1988 ◽  
Vol 110 (1) ◽  
pp. 38-41 ◽  
Author(s):  
G. P. Peterson ◽  
L. S. Fletcher
Keyword(s):  
Experimental Investigation ◽  
Stainless Steel ◽  
Thermal Contact ◽  
Spherical Particles ◽  
Thermal Contact Conductance ◽  
Packed Beds ◽  
Contact Conductance ◽  
Analytical Expression ◽  
Flat Surfaces ◽  
Stainless Steel 304

An experimental investigation was conducted to determine the thermal contact conductance of packed beds of spherical particles in contact with flat surfaces. Beds comprised of four materials, Aluminum 2017-T4, Yellow Brass, Stainless Steel 304, and Chromium Alloy AISI 52100, all in contact with flat Stainless Steel 304, surfaces were evaluated in a vacuum environment, at a mean interface temperature of 66°C. In addition to the experimental program, an analytical expression was developed by combining previous work performed by other investigators. The results of the experimental investigation are compared with the analytical expression and indicate that an accurate method of predicting the thermal contact conductance at the interface between beds of spherical particles and nominally flat surfaces has been identified.

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