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.

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.

An Improved Method of Thermal Resistance Measurement for Variable Thermal Resistors

2007 ◽  
Author(s):  
Hyeun-Su Kim ◽  
Hyun Oh Song ◽  
Thomas W. Kenny
Keyword(s):  
Thermal Resistance ◽  
Measurement Method ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Response ◽  
Resistance Measurement ◽  
Response Signal ◽  
Improved Method ◽  
Temperature Signal ◽  
Thermal Resistors

As part of the study and development of a variable thermal resistor (VTR), we present an improved thermal resistance measurement method for the VTR in the presence of unwanted signal drifting. To measure the change of thermal resistance, instead of waiting for the steady state value of the temperature signal, we repeatedly measure only the early transient part of the thermal response signal and then fit to get thermal resistance estimation. The required lengths of measurement were studied for the tests with various thermal time constants. Using this method, we performed thermal switching tests with various material pairs in contact in order to find the material pair that minimizes thermal contact resistance.

Modeling and Estimating Simulated Burn Depth Using the Perfusion and Thermal Resistance Probe

2013 ◽  
Vol 7 (3) ◽  
Author(s):  
Abdusalam Al-Khwaji ◽  
Brian Vick ◽  
Tom Diller
Keyword(s):  
Mathematical Model ◽  
Heat Flux ◽  
Parameter Estimation ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Core Temperature ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Blood Perfusion ◽  
Thermal Event

A new thermal perfusion probe operates by imposing a thermal event on the tissue surface and directly measuring the temperature and heat flux response of the tissue with a small sensor. The thermal event is created by convectively cooling the surface with a small group of impinging jets using room temperature air. The hypothesis of this research is that this sensor can be used to provide practical burn characterization of depth and severity by determining the thickness of nonperfused tissue. To demonstrate this capability the measurement system was tested with a phantom tissue that simulates the blood perfusion of tissue. Different thicknesses of plastic were used at the surface to mimic layers of dead tissue. A mathematical model developed by Alkhwaji et al. (2012, “New Mathematical Model to Estimate Tissue Blood Perfusion, Thermal Contact Resistance and Core Temperature,” ASME J. Biomech. Eng., 134, p. 081004) is used to determine the effective values of blood perfusion, core temperature, and thermal resistance from the thermal measurements. The analytical solutions of the Pennes bioheat equation using the Green's function method is coupled with an efficient parameter estimation procedure to minimize the error between measured and analytical heat flux. Seven different thicknesses of plastic were used along with three different flow rates of perfusate to simulate burned skin of the phantom perfusion system. The resulting values of thermal resistance are a combination of the plastic resistance and thermal contact resistance between the sensor and plastic surface. Even with the uncertainty of sensor placement on the surface, the complete set of thermal resistance measurements correlate well with the layer thickness. The values are also nearly independent of the flow rate of the perfusate, which shows that the parameter estimation can successfully separate these two parameters. These results with simulated burns show the value of this minimally invasive technique to measure the thickness of nonperfused layers. This will encourage further work with this method on actual tissue burns.

Study on Thermal Contact Resistance for Heat Transfer of High Power LED Packaging

2011 ◽  
Vol 199-200 ◽  
pp. 1477-1481
Author(s):  
Guo Tao Ren ◽  
Kai Lin Pan ◽  
Wei Tao Zhu ◽  
Jiao Pin Wang ◽  
Jing Huang
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
High Power ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Fem Simulation ◽  
Total Thermal Resistance ◽  
Simulation And Experiment ◽  
Thermal Transient

Thermal contact resistance is one of key technologies for heat transfer of high power light emitting diodes (LED) packaging. In this paper, based on the resistance network model of LED packaging, a 3-D finite element simulation model (FEM) is established and thermal transient testing experiments are also performed by Thermal Transient tester (T3Ster). Experiment date indicates thermal contact resistance for 48% of the total thermal resistance. The thermal interface material (TIM) layer of high power LED packaging is studied to analysis thermal contact resistance which impacts on thermal performance of LED packaging. The total thermal resistance and the thermal resistance of TIM layer are separately calculated from simulation and experiment. To the resistance of TIM layer, the result of experiment is only a 1% error compared to the result of FEM simulation. Therefore, The FEM simulation and experiment are mutually validated. In order to thoroughly study on thermal contact resistance, based on the principle of structure function, thermal resistance of three different types of TIM layer between metal core printed circuit board (MCPCB) and aluminum heat sink are measured and compared. Experiment results indicate that the quality of interface affects the thermal contact resistance to a great extent.

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.

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