Numerical Determination of Thermal Contact Resistance for Nonisothermal Forging Processes

2000 ◽  
Vol 122 (4) ◽  
pp. 776-784 ◽  
Author(s):  
A.-S. Marchand ◽  
M. Raynaud

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]

Volume 3 ◽  
2004 ◽  
Author(s):  
F. J. Hong ◽  
H.-H. Qiu

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.


2016 ◽  
Vol 18 (35) ◽  
pp. 24164-24170 ◽  
Author(s):  
Yang Hong ◽  
Jingchao Zhang ◽  
Xiao Cheng Zeng

Interfacial thermal conductance plays a vital role in defining the thermal properties of nanostructured materials in which heat transfer is predominantly phonon mediated.


2014 ◽  
Vol 941-944 ◽  
pp. 2465-2468 ◽  
Author(s):  
Yong Zhen Liu ◽  
Zhi Shi Huang ◽  
Bin Feng ◽  
Jin He Wei ◽  
Jian Min Zeng

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.


1975 ◽  
Vol 97 (2) ◽  
pp. 305-307 ◽  
Author(s):  
T. R. Thomas

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.


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