A Model of the Contact Thermal Resistance of Vertical Carbon Nanotube Arrays

2016 ◽  
Author(s):  
Jin Zhang ◽  
Bo Shi
Keyword(s):  
Carbon Nanotube ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Interfacial Thermal Resistance ◽  
Elastic Rod ◽  
Aligned Carbon Nanotubes ◽  
Vertically Aligned ◽  
Thin Elastic Rod

This paper developes a model to predict the thermal contact resistance of the vertically aligned carbon nanotubes (VACNTs). The model includes the effects of CNT array properties and surface roughness, with the aim of providing useful information for optimizing CNT array thermal contact resistance. The contact resistance is consisted of two parts: interfacial thermal resistance and constriction thermal resistance. The carbon nanotube (CNT) is treated as a thin elastic rod and macroscopic mechanical is used to calculate the mechanical properties of CNT. Greenwood-Williamson (GW) model is used to describe the roughness. The interfacial thermal resistance is calculated by molecular dynamics. The calculated values are in good agreement with experimental data. The interfacial thermal resistance is the domain major factor.

Design and Verification of a Low-Powered Pre-Programmable In-Package Temperature Controller

2006 ◽  
Author(s):  
Hyeun-Su Kim ◽  
Hsien-Hsin Liao ◽  
Byeong-hee Lee ◽  
Thomas W. Kenny
Keyword(s):  
Thermal Resistance ◽  
Contact Resistance ◽  
Temperature Change ◽  
Thermal Contact Resistance ◽  
Operating Temperature ◽  
Electrostatic Force ◽  
Thermal Contact ◽  
Temperature Regulator ◽  
Thermal Resistors ◽  
Device Test

A zero power passive temperature regulator has been studied and designed to maintain electric chip operating temperature using a variable thermal resistor. Apart from the passive temperature regulator design, we also present active variable thermal resistors using electrostatic force to actuate the device. Test samples were fabricated to verify these two designs and we observed the temperature change of a heated chip due to thermal resistance changes. This study estimated and measured the thermal contact resistance and the force required to remove it.

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 Conductivity Measurement of Vertically Aligned Single-Walled Carbon Nanotubes Utilizing Temperature Dependence of Raman Scattering

2011 ◽  
Author(s):  
Kei Ishikawa ◽  
Shohei Chiashi ◽  
Saifullah Badar ◽  
Theerapol Thurakitseree ◽  
Takuma Hori ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Contact Resistance ◽  
Temperature Dependence ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Single Walled Carbon Nanotubes ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes ◽  
Swnt Film

We present a method for measuring the thermal conductivity and the thermal contact resistance between the film and the substrate of vertically-aligned single-walled carbon nanotubes (VA-SWNTs) grown on Si substrate by ACCVD (Alcohol Catalytic Chemical Vapor Deposition) method, utilizing temperature dependence of the Raman spectrum obtained from SWNTs. The method utilizes the excitation laser of the Raman system to heat the VA-SWNT film and measure the temperature simultaneously. The method finds the thermal conductivity of the VA-SWNT film to be around 1 Wm−1K−1 and the thermal contact resistance between the substrate and the film to be around 10−5∼10−6 m2KW−1. The obtained film thermal conductivity is converted into equivalent thermal conductivity of an individual SWNT, whose value is several tens of Wm−1K−1, and is more than an order of magnitude smaller than the reports on individual SWNTs.

Modeling and Experimental Characterization of Metal Microtextured Thermal Interface Materials

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
R. Kempers ◽  
A. M. Lyons ◽  
A. J. Robinson
Keyword(s):  
Thermal Resistance ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Small Scale ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Main Challenge

A metal microtextured thermal interface material (MMT-TIM) has been proposed to address some of the shortcomings of conventional TIMs. These materials consist of arrays of small-scale metal features that plastically deform when compressed between mating surfaces, conforming to the surface asperities of the contacting bodies and resulting in a low-thermal resistance assembly. The present work details the development of an accurate thermal model to predict the thermal resistance and effective thermal conductivity of the assembly (including contact and bulk thermal properties) as the MMT-TIMs undergo large plastic deformations. The main challenge of characterizing the thermal contact resistance of these structures was addressed by employing a numerical model to characterize the bulk thermal resistance and estimate the contribution of thermal contact resistance. Furthermore, a correlation that relates electrical and thermal contact resistance for these MMT-TIMs was developed that adequately predicted MMT-TIM properties for several different geometries. A comparison to a commercially available graphite TIM is made as well as suggestions for optimizing future MMT-TIM designs.

Characterization of Carbon Nanotube Forest Interfaces Using Time Domain Thermoreflectance

2015 ◽  
Author(s):  
Thomas L. Bougher ◽  
John H. Taphouse ◽  
Baratunde A. Cola
Keyword(s):  
Heat Transfer ◽  
Contact Resistance ◽  
Time Domain ◽  
Thermal Contact ◽  
Thermal Interface Materials ◽  
Length Scales ◽  
Aligned Carbon Nanotubes ◽  
Theoretical Predictions ◽  
Vertically Aligned

Forests comprised of nominally vertically aligned carbon nanotubes (CNTs) are excellent candidates for thermal interface materials (TIMs) due to their theoretically predicted outstanding thermal and mechanical properties. Unfortunately, due to challenges in the synthesis and characterization of these materials reports of the thermal conductivity and thermal contact resistance of CNT forests have varied widely and typically fallen far short of theoretical predictions. In particular, the micro- and nano-length scales characteristic of the heat transfer in CNT forests pose significant challenges and may lead to misreported results. Here we examine the ability of a popular and well-established thermal metrology technique, time-domain thermoreflectance (TDTR), to resolve the properties of CNT forest TIMs. The characteristic heating frequencies of TDTR (1–10 MHz) are used to probe heat transfer at length scales spanning ∼0.1–1 μm, applicable for measuring the contact resistance between the CNT forest free tips and an opposing substrate. We identify the range of CNT forest-opposing substrate interface resistances that can be resolved with TDTR, and simultaneously demonstrate the effectiveness of several processes developed to reduce the resistance of these interfaces. The limitations of characterizing CNT forests with TDTR are discussed in terms of uncertainty and sensitivity to parameters of interest.

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