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.

Numerical analysis of the temperature profile during the laser-assisted automated fiber placement of CFRP tapes with thermoplastic matrix

2017 ◽  
Vol 31 (12) ◽  
pp. 1563-1586 ◽  
Author(s):  
Andreas Kollmannsberger ◽  
Roland Lichtinger ◽  
Franz Hohenester ◽  
Christoph Ebel ◽  
Klaus Drechsler
Keyword(s):  
Carbon Fiber ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Fiber Placement ◽  
Composite Layers ◽  
Automated Fiber Placement ◽  
Geometric Boundary ◽  
Laser Heat Source ◽  
Placement Machine

In this study, a thermodynamic model of a laser-assisted automated thermoplastic fiber placement process is developed and validated. The main focus is on modeling the heat transfer into the composite with a laser heat source, the thermal properties of the tape, and the resulting heat distribution in the part, the mold, and the compaction roller. A new integrated analytical method is presented to calculate the energy input of the laser based on the geometric boundary conditions, including first-order reflection and laser shadow. The carbon fiber/polyethersulphone tape is modeled by combining literature properties of carbon fiber and matrix as well as based on experimental data of the tape itself. Also a thermal contact resistance between the tape layers is modeled based on a literature model and own experimental measurements. The created model is discretized and implemented in a 2-D finite difference code. With the help of this simulation, the temperature distribution is calculated during layup. The influence of a possible thermal contact resistance between the composite layers is investigated. Furthermore, an experiment with a thermoplastic fiber placement machine from Advanced Fibre Placement Technology GmbH (AFPT) was conducted in order to evaluate the simulation. The simulation and the experiment show a good agreement and prove that thermal contact resistance between the layers is negligible for the investigation process.

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.

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.

Effect of Press on Thermal Contact Resistance

2011 ◽  
Vol 217-218 ◽  
pp. 1541-1546
Author(s):  
Hai Ming Huang ◽  
Wen Jiao
Keyword(s):  
Heat Transfer ◽  
Aluminum Alloy ◽  
Carbon Fiber ◽  
Contact Resistance ◽  
Polymer Composites ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Epoxy Composites ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced

The thermal contact resistance between polymer composites and aluminum alloy is the main parameters of thermal control design in the field of space and its heat transfer mechanism is very complex. This work is to combine experimental and numerical approaches to evaluate the nature of thermal contact between polymer composites and aluminum alloy. Thermal contact resistance between carbon fiber reinforced epoxy composites and aluminum alloy 380 was measured experimentally. And based on the finite element method, the simulations on heat transfer between polymer composites and aluminum alloy have been performed and compared with experiment results. The results show that the thermal contact resistance between carbon fiber reinforced epoxy composites and aluminum alloy is not negligible and strongly correlated with pressure.

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.

3-Omega-T-Type Method for Measuring the Thermophysical Properties of Micro/Nanowires

2011 ◽  
Author(s):  
Xing Zhang ◽  
Jianli Wang
Keyword(s):  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Effusivity ◽  
Temperature Oscillation ◽  
Thermal Impedance ◽  
Hot Wire ◽  
Type Method ◽  
3 Omega ◽  
Interstitial Material ◽  
Lock In

A novel 3ω-T type probe method is developed to investigate the thermal effusivity of micro/nanowires. In this method, a short hot wire subjected to an alternating current serves simultaneously as a heater and a thermometer, and a test wire is attached to the midpoint of the hot wire with an interstitial material. A measurement system based on a virtual lock-in is developed to measure the thermal impedance of the interposer and the thermal effusivity of the test wire. The same value of thermal effusivity is obtained with the presence of different interposers, and the interposer with small thermal impedance gives a decrease of the temperature oscillation of the hot wire. Using this method, the thermal resistances of bare metallic junctions are measured as a function of temperature. For the junction established by two crossed platinum wires with small diameters, the thermal contact resistance is found to decrease as temperature increases, which can possibly be explained the plastic deformation of the microscopic contacts.

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