Experimental Study on Thermal Contact Resistance Improvement for Optical Fiber by Using Low-Melting Temperature Alloy

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Wen-Xiao Chu ◽  
Hao-Yu Lin ◽  
Chi-Chuan Wang
Keyword(s):  
Surface Roughness ◽  
Optical Fiber ◽  
Contact Resistance ◽  
Melting Temperature ◽  
Contact Pressure ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Heating Load ◽  
Effect Of Surface

Abstract This paper presents an experimental analysis for minimizing the thermal contact resistance (R) between an optical fiber and copper heat sink by using the low-melting temperature alloy (LMTA) as the thermal interface material (TIM) subject to high-flux operation (up to 250 W ⋅ m−1). For the cases without LMTA, the temperature rise (ΔT) can easily surpass 195 °C at a heating load of 25 W ⋅ m−1. By contrast, ΔT is dramatically reduced to be less than 1 °C with LMTA as TIM with a much higher heating power of 150 W ⋅ m−1. The corresponding thermal resistance (R) can be reduced from 6.5–8.2 K ⋅ m ⋅ W−1 to 0.004–0.013 K ⋅ m ⋅ W−1. The improvement is far superior to existing studies. Besides, decreasing the surface roughness and increasing contact pressure also help to reduce R, especially for the cases when the LMTA is not melted. As the LMTA melts, a significant reduction of R by 56% is achieved as compared to the case without melting. The effect of surface roughness and contact pressure on the thermal contact resistance is also examined, and it is found that the influences are small once LMTA melts.

Experimental and Theoretical Study on the Effect of Pressure and Surface Roughness on Thermal Contact Resistance With LMA As TIM

2019 ◽  
Author(s):  
Yulong Ji ◽  
Jiantong Xu ◽  
Weichen Gao ◽  
Huilong Yan ◽  
Fengmin Su ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Theoretical Model ◽  
Contact Resistance ◽  
Melting Temperature ◽  
Contact Pressure ◽  
Thermal Contact Resistance ◽  
Layer Structure ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Steady State Method

Abstract The recent research show that low melting temperature alloys (LMA) is a prospective thermal interface material (TIM). However, the effect of surface roughness and interface contact pressure on the thermal contact resistance with LMA as TIM is unclear. In the current research, copper plates with surface roughness of 0.28 μm, 0.54 μm, 0.96 μm and 2.59 μm were fabricated to make different test samples. Low melting temperature alloys Ga62.5In21.5Sn16 was used as TIM to make the Cu-LMA-Cu three-layer structure samples. The thermal contact resistance of these samples under different pressure of 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.4 MPa and 0.6 MPa were measured based on the steady state method. The results show that when the pressure of 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.4 MPa, 0.6MPa is applied to the samples, the thermal contact resistance of sample with surface roughness of 0.28 μm decreased by 74.3%, 71.1%, 70.1%, 71.5%, 70.8%, 70.1% compared with that of the sample with surface roughness of 2.59 μm. In order to further study the influence of the factors on the thermal contact resistance, a theoretical model of solid-liquid-solid thermal contact resistance with contact pressure and surface roughness as factors was developed. Based on theoretical model, it is concluded that (1) the thermal contact resistance decreases as the pressure increases, and gradually stabilizes; (2) as the surface roughness increases, the thermal contact resistance increases; (3) As the surface roughness decreases, the influence of contact pressure on thermal contact resistance decreases. The above conclusions were verified by test results.

On Simple Prediction Method for Thermal Contact Resistance Between Wavy Surfaces With Thermal Interface Material Under Low Mean Nominal Contact Pressure (Fundamental Study Based on 1-D Model)

2015 ◽  
Author(s):  
Toshio Tomimura ◽  
Yasushi Koito ◽  
Taewan Do ◽  
Masaru Ishizuka ◽  
Tomoyuki Hatakeyama
Keyword(s):  
Contact Resistance ◽  
Contact Pressure ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Surface Model ◽  
Contact Interface ◽  
Fundamental Study ◽  
Thermal Interface ◽  
Wavy Surfaces

The thermal contact resistance (TCR) is the crucial issue in the field of heat removal from systems like electronic equipment, satellite thermal control systems, and so on. To cope with the problem, a lot of studies have been done mainly for flat rough surfaces. However, as pointed out so far, there are still wide discrepancies among measured and predicted TCRs, even for similar materials. To investigate the key factors for the abovementioned discrepancies, a fundamental analysis was conducted in our previous study [1] using a simple contact surface model, which was composed of the unit cell model proposed by Tachibana [2] and Sanokawa [3]. Furthermore, by introducing a 2-D microscopic surface model, which consists of random numbers and Abbott’s bearing area curve, the effects of surface waviness and roughness on the temperature fields near the contact interface have been investigated microscopically [4]. In this study, based on a 1-D wavy surface model, a fundamental study has been conducted to predict TCR and the thermal contact conductance (TCC), which is a reciprocal of TCR, between wavy surfaces with the thermal interface material (TIM) under a relatively low mean nominal contact pressure of 0.1–1.0 MPa. From comparison between the calculated and measured results, it has been shown that, in spite of a simple 1-D analysis, the present model predicts the temperature drop at the contact interface, which is obtained as the product of TCR and the heat rate flowing through TIM, within some 10 to 60% error for a TIM with the thermal conductivity of 2.3 W/(m·K) and the initial thickness of 0.5, 1 and 2 mm.

scholarly journals Noncured Graphene Thermal Interface Materials for High-Power Electronics: Minimizing the Thermal Contact Resistance

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1699
Author(s):  
Sriharsha Sudhindra ◽  
Fariborz Kargar ◽  
Alexander A. Balandin
Keyword(s):  
Contact Resistance ◽  
High Power ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Wide Band ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Total Thermal Resistance ◽  
Thermal Interface ◽  
Interface Materials

We report on experimental investigation of thermal contact resistance, RC, of the noncuring graphene thermal interface materials with the surfaces characterized by different degree of roughness, Sq. It is found that the thermal contact resistance depends on the graphene loading, ξ, non-monotonically, achieving its minimum at the loading fraction of ξ ~15 wt %. Decreasing the surface roughness by Sq~1 μm results in approximately the factor of ×2 decrease in the thermal contact resistance for this graphene loading. The obtained dependences of the thermal conductivity, KTIM, thermal contact resistance, RC, and the total thermal resistance of the thermal interface material layer on ξ and Sq can be utilized for optimization of the loading fraction of graphene for specific materials and roughness of the connecting surfaces. Our results are important for the thermal management of high-power-density electronics implemented with diamond and other wide-band-gap semiconductors.

scholarly journals Test Rig for Applied Experimental Investigations of the Thermal Contact Resistance at the Blade-Rotor-Connection in a Steam Turbine

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Dennis Toebben ◽  
Xavier E. R. de Graaf ◽  
Piotr Luczynski ◽  
Manfred Wirsum ◽  
Wolfgang F. D. Mohr ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Steam Turbine ◽  
Contact Pressure ◽  
Rotational Speed ◽  
Thermal Contact Resistance ◽  
Thermal Stresses ◽  
Thermal Contact ◽  
Experimental Investigations ◽  
Molybdenum Steel ◽  
Bottle Neck

Recent studies have shown that in a prewarming, respectively, warm-keeping operation of a steam turbine, the blades and vanes transport most of the heat to the thick-walled casing and rotor. Thereby, a thermal bottle-neck arises at the connection between the blade root and the rotor. The thermal contact resistance (TCR) at these interfaces affects the temperature distribution and thus the thermal stresses in the rotor. The present paper introduces an experimental setup, which is designed to quantify the TCR at the blade-rotor-connection of a steam turbine. An uncertainty analysis is presented, which proves that the average measurement uncertainties are less than one percent. The experiments especially focus on the investigation of the contact pressure, which is a function of the rotational speed. Therefore, the results of several steady-state measurements under atmospheric and evacuated atmosphere using a high temperature-resistant chromium-molybdenum steel are presented. For the evaluation of the TCR, a numerical model of the specimen is developed in addition to a simplified 1D approach. The results show a significantly increasing TCR with decreasing contact pressure, respectively, rotational speed.

scholarly journals Contribution to the Study of Solid-Solid Thermal Contact Resistances--A Comparative Study

2021 ◽  
Vol 45 (4) ◽  
pp. 267-272
Author(s):  
Rahmouna Cheriet ◽  
Bourassia Bensaad ◽  
Fatiha Bouhadjela ◽  
Soufyane Belhenini ◽  
Mohammed Belharizi
Keyword(s):  
Contact Resistance ◽  
Contact Pressure ◽  
Mixed Method ◽  
Thermal Contact Resistance ◽  
Low Cost ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Empirical Models ◽  
Three Dimensional Finite Element ◽  
Semi Empirical

This study presents a mixed numerical / semi-empirical approach that primarily aimed to estimate the thermal contact resistance between two solids. The results obtained by this mixed method were compared and validated by experimental measurements of this resistance. Three semi-empirical models were used, namely the Mikic model, the Yovanovich model and the Antonetti model. The three-dimensional finite element numerical simulation was used to estimate the contact pressure between the two solids. Then this contact pressure obtained numerically was compared to the hardness of the solids in contact. The findings indicated that the numerically obtained contact pressures were close to hardness. Therefore, the hardness, which is usually used as an input variable in semi-empirical models, was replaced by the contact pressure. The thermal contact resistance obtained by this mixed method was then compared with the experimental one. The outcomes obtained from this comparison turned out to be very conclusive and can therefore be used to reinforce our approach which can actually be viewed as a reliable and low-cost method for estimating the thermal contact resistance between solids in contact.

Characterization of Thermal Contact Resistance in Metal Micro-Textured Thermal Interface Materials Using Electrical Contact Resistance Measurements

2010 ◽  
Vol 297-301 ◽  
pp. 1190-1198 ◽  
Author(s):  
R. Kempers ◽  
A.J. Robinson ◽  
A. Lyons
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Applied Pressure ◽  
Thermal Interface Material ◽  
Metal Foil ◽  
Electrical Contact Resistance ◽  
Thermal Interface ◽  
Thermally Conductive

A novel Metal Micro-Textured Thermal Interface Material (MMT-TIM) has been developed to address a number of shortcomings in conventional TIMs. This material consists of a thin metal foil with raised micro-scale features that plastically deform under an applied pressure thereby creating a continuous, thermally conductive, path between the mating surfaces. One of the difficulties in experimentally characterizing MMT-TIMs however, is distinguishing the bulk thermal resistance of the MMT-TIM from the thermal contact resistance that exists where it contacts the test apparatus. Since these materials are highly electrically conductive, this study attempts to employ electrical contact resistance measurements to estimate their thermal contact resistance. Tests using flat silver and gold specimens of known bulk thermal conductivity were used to develop a correlation between electrical and thermal contact resistance. This relationship was then employed to estimate the thermal contact resistance of a prototype silver MMT-TIM and indicates the thermal contact resistance accounts for approximately 10% of the measured thermal contact resistance. A number of issues related to this technique are discussed as well as its future outlook.

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