Extrapolation Errors in Thermal Contact Resistance Measurements

1975 ◽  
Vol 97 (2) ◽  
pp. 305-307 ◽  
Author(s):  
T. R. Thomas
Keyword(s):  
Temperature Gradient ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Temperature Drop ◽  
Interface Temperature ◽  
Better Than

In the classic split-bar determination of thermal contact resistance the temperature drop across the interface is estimated by extrapolating a temperature gradient measured remotely. It is shown that this can give rise to substantial errors which cannot greatly be reduced by increasing the number of measurements. It is suggested that due to extrapolation errors few interface temperature drops have ever been determined to better than 1/2 °K, and that this may account for some of the discrepancies between published contact resistances, particularly those measured at high loads.

Numerical Study on Substrate Remelting, Flow, and Resolidification in Microcasting

Volume 3 ◽  
2004 ◽  
Author(s):  
F. J. Hong ◽  
H.-H. Qiu
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Numerical Study ◽  
Thermal Contact ◽  
Spreading Factor ◽  
Droplet Spreading ◽  
Molten Droplet ◽  
Front Shape ◽  
Complex Fluid

A large and highly superheated molten droplet impacting onto the substrate during the microcasting was studied numerically. In this study, same material for both the droplet and the substrate was considered. Numerical model including the complex fluid dynamics of droplet, interfacial thermal contact resistance, and substrate remelting, as well as the flow in the substrate has been developed. Numerical simulations of a microcasting experiment were conducted with the different thermal contact resistances. The results of simulations show that the spreading factor and substrate remelting agreed well with the experimental data under the assumption of an appropriate thermal contact resistance. It is also found that the thermal contact resistance plays an important role not only in droplet spreading arrest but also in the determination of substrate remelting volume and remelting front shape. The effects of droplet impacting velocity, superheat and substrate temperature were also investigated.

Experimental Investigation of Contact Resistance Across Pressed Lead and Aluminum Contact in Vacuum

2000 ◽  
Author(s):  
Xiao Ma ◽  
Jamil A. Khan ◽  
Curtis A. Rhodes ◽  
Allen Smith ◽  
L. Larry Hamm
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Cooling Water ◽  
External Pressure ◽  
Interface Temperature ◽  
Pressure Surface ◽  
Increasing Temperature

Abstract In a proposed nuclear application (production of Tritium using an accelerator, Accelerator Production of Tritium (APT)) lead is proposed to be used as a shield in the blanket module. This lead will be encased in aluminum cladding. The energy transfer rate from the lead to the cooling water will be a function of the thermal contact resistance (TCR) between lead and aluminum. Presently, data for contact resistance for this application does not exists in the literature. An experimental investigation has been conducted to determine the thermal contact resistance between lead and aluminum in vacuum. In this study we investigate the effect of pressure, surface roughness and interface temperature on the contact resistance. The experimentally determined range of contact resistance was found to be from 3.74×10−4K-m2/W to 11.45×10−4K-m2/W at 100°C∼200°C under 120∼370psi (0.827∼2.551MPa). The contact resistance increases to 168×10−4K-m2/W at small external pressure of 2.0∼3.9psi (0.013∼0.027MPa). The contact resistance decreases with increasing in contact pressure. Interface temperature and surface roughness do not affect the contact resistance significantly. There is a slight increase in contact conductance with increasing temperature. The experimental results provide contact resistance data, which should be a good reference for the APT design evaluation.

Application of Thermal Contact Resistance in Simulation of Heat Dissipation by CPU Heat Sinks Based on ANSYS

2014 ◽  
Vol 941-944 ◽  
pp. 2465-2468 ◽  
Author(s):  
Yong Zhen Liu ◽  
Zhi Shi Huang ◽  
Bin Feng ◽  
Jin He Wei ◽  
Jian Min Zeng
Keyword(s):  
Contact Resistance ◽  
Heat Dissipation ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Heat Sinks ◽  
Ansys Software ◽  
Electronic Elements ◽  
Good Heat ◽  
Main Factor

With development in electronic technology, more and more electronic elements have been integrated into one chip, which has resulted in the cooling problem of the chips. In this case, heat dissipation has become the main factor that affecting the design reliability and package cost. Therefore, good heat dissipation designs are urgently need to solve the problem. An important issue resulted from simulation of heat dissipation is the determination of boundary condition between the heat sink and the CPU. The concept of thermal contact resistance was introduced to simulation of heat dissipation of CPU heat sinks in this paper. The temperature distribution of CPU heat sinks was calculated Based on ANSYS software. The result of calculation can help to understand the heat transfer characteristics of CPU heat sinks, and also offer a reference for the design and improvement of the electronic equipment.

Numerical Determination of Thermal Contact Resistance for Nonisothermal Forging Processes

2000 ◽  
Vol 122 (4) ◽  
pp. 776-784 ◽  
Author(s):  
A.-S. Marchand ◽  
M. Raynaud
Keyword(s):  
Thermal Properties ◽  
Finite Difference Method ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Numerical Study ◽  
Thermal Contact ◽  
Numerical Determination ◽  
Predictive Capability ◽  
Interface Geometry

A numerical study is conducted to estimate the thermal contact resistance (TCR) between the tool and the workpiece during slow nonisothermal forging processes. A finite difference method is used to determine the TCR from a thermomechanical microscopic model. Correlations of the numerical results are developed for the TCR as a function of the interface geometry and the thermal properties. The method used to introduce these correlations in forging softwares, to account for a time and space-dependent TCR instead of a constant arbitrary value, is given. The predictive capability of the correlations is partially validated by comparing their outputs with TCR results from the literature. [S0022-1481(00)00903-8]

scholarly journals Effects of contact pressure and interface temperature on thermal contact resistance between 2Cr12NiMoWV/BH137 and γ-TiAl/2Cr12NiMoWV interfaces

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 313-324
Author(s):  
Yuwei Liu ◽  
Yameng Ji ◽  
Fuhao Ye ◽  
Weizheng Zhang ◽  
Shujun Zhou
Keyword(s):  
Contact Resistance ◽  
Contact Pressure ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Interface Temperature ◽  
Ambient Atmosphere ◽  
Heat Resistant Steel ◽  
Steady State Temperature

Thermal contact resistance between interfaces is an important parameter in the analysis of temperature distribution for structural components. Thermal contact resistance between heat resistant steel 2Cr12NiMoWV/aluminum alloy BH137 interfaces and 2Cr12NiMoWV/titanium alloy ?-TiAl interfaces were experimentally investigated in the present paper. The effects of contact pressure and interface tem-perature were detailed. The temperature of contacting surfaces was from 80- 250?, and the contact pressure ranged from 2-17 MPa. All experiments were conducted in ambient atmosphere. Results showed that thermal contact resistance decreases with an increment of interface temperature or contact pressure. Under the same conditions of contact pressure and interface temperature, thermal contact resistance between 2Cr12NiMoWV and BH137 interfaces is lower than that between 2Cr12NiMoWV and ?-TiAl interfaces. The temperature dependence of thermal conductivity and mechanical properties was analyzed to explain the results. Furthermore, with the piston and piston pin as the research object, steady state temperature fields were simulated in cases of considering thermal contact resistance and without considering thermal contact resistance, respectively. The results showed that the maximum temperature of the piston pin will be lower when thermal contact resistance is considered.

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