scholarly journals Identification of the Thermal Conductance of a Hidden Barrier from Outer Thermal Data

2021 ◽  
Vol 8 (1) ◽  
pp. 16
Author(s):  
Gabriele Inglese ◽  
Roberto Olmi ◽  
Agnese Scalbi
Keyword(s):  
Heat Transfer ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Thin Plate ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Contact Conductance ◽  
Composite Slab ◽  
Thermal Data ◽  
Investigate Heat Transfer

Hidden defects affecting the interface in a composite slab are evaluated from thermal data collected on the upper side of the specimen. First we restrict the problem to the upper component of the object. Then we investigate heat transfer through, the inaccessible interface by means of Thin Plate Approximation. Finally, a Fast Fourier Transform is used to filter data. In this way, we obtain a reliable reconstruction of simulated flaws in thermal contact conductance corresponding to appreciable defects of the interface.

Recent Developments in Contact Conductance Heat Transfer

1988 ◽  
Vol 110 (4b) ◽  
pp. 1059-1070 ◽  
Author(s):  
L. S. Fletcher
Keyword(s):  
Heat Transfer ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Contact Conductance ◽  
Contact Conductance ◽  
Thermal Rectification ◽  
Numerical Studies ◽  
Wide Range ◽  
Theoretical Investigations ◽  
Recent Developments

The characteristics of thermal contact conductance are increasingly important in a wide range of technologies. As a consequence, the number of experimental and theoretical investigations of contact conductance has increased. This paper reviews and categorizes recent developments in contact conductance heat transfer. Among the topics included are the theoretical/analytical/numerical studies of contact conductance for conforming surfaces and other surface geometries; the thermal conductance in such technological areas as advanced or modern materials, microelectronics, and biomedicine; and selected topics including thermal rectification, gas conductance, cylindrical contacts, periodic and sliding contacts, and conductance measurements. The paper concludes with recommendations for emerging and continuing areas of investigation.

Thermal and Electrical Conductance of Pressure Tube/Calandria Tube Interface

2020 ◽  
Author(s):  
Chukwudi Azih ◽  
Reilly MacCoy ◽  
Hazem Mazhar ◽  
Chris Fraser
Keyword(s):  
Heat Transfer ◽  
Thermal Contact ◽  
Electrical Conductance ◽  
Thermal Conductance ◽  
Pressure Tube ◽  
Thermal Contact Conductance ◽  
Interface Pressure ◽  
Contact Conductance ◽  
Engineered Systems ◽  
Interface Thermal Conductance

Abstract In some engineered systems, the interface thermal conductance is a key parameter that governs the heat transfer behaviour of components in solid-solid contact. For example, in certain postulated accident scenarios for CANDU reactors, the pressure tube (PT) may deform into contact with the calandria tube (CT) to form a more direct path for heat transfer from the fuel to the moderator. There have been no direct measurements of interface thermal conductance in integrated “Contact boiling” experiments designed to mimic this Loss-of-coolant accident (LOCA) scenario due to the geometrical limits of the test components and the cumbersome nature of the instrumentation required to extract contact conductance data. It has been noted that the modelling of the contact conductance is one of the main sources of uncertainty in predicting the outcome of the contact boiling experiments that mimic LOCA scenarios. The present study demonstrated an analogy between the electrical and thermal contact conductance for PT/CT interfaces. The range of interface pressure and interface temperatures studies are selected to match the expected range of conditions during a CANDU LOCA scenario. The experiment setup consists of two sets of specimen representing PT and CT material. The specimen are instrumented with four K-type thermocouples in sequence to capture the temperature gradient imposed via a three-chamber oven. Within a range of interface pressures from 2 to 7 MPa and a temperature range from 510 to 720°C, the analogy is independent of the interface pressure or the load applied. This demonstrates the measurement of the electrical conductance between the PT and CT in contact boiling as a promising technique for obtaining in-situ information on the thermal contact conductance during integrated experiments.

Heat Conduction Through a Layered Pressure Vessel Wall

1986 ◽  
Vol 108 (4) ◽  
pp. 418-422
Author(s):  
M. Ueda ◽  
M. Kinugawa ◽  
Y. Hara ◽  
K. Yamazato
Keyword(s):  
Heat Conduction ◽  
Pressure Vessel ◽  
Vessel Wall ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Postweld Heat Treatment ◽  
Pressure Vessels ◽  
Scale Model ◽  
Thermal Contact Conductance ◽  
Simplified Method

Heat conduction tests of a layered pressure vessel wall were performed using full-scale model pressure vessel courses. Thermal conductance between layers was estimated from the test results. A simplified method, developed for the thermal analysis of layered-wall pressure vessels during postweld heat treatment and actual operation, includes thermal contact conductance at the layer interfaces which depends upon the contact pressure and gap height. Temperature changes calculated using the simplified method agreed well with the experiments.

scholarly journals Demonstration of a Compliant Micro-Spring Array As a Thermal Interface Material for Pluggable Optoelectronic Transceiver Modules

2019 ◽  
Author(s):  
Jin Cui ◽  
Liang Pan ◽  
Justin A. Weibel
Keyword(s):  
Heat Sink ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Interface Material ◽  
Thermal Contact Conductance ◽  
Compression Pressure ◽  
Thermal Interface ◽  
Operation Temperature ◽  
Optical Module ◽  
Dry Contact

Abstract Pluggable optoelectronic transceiver modules are widely used in the fiber-optic communication infrastructure. It is essential to mitigate thermal contact resistance between the high-power optical module and its riding heat sink in order to maintain the required operation temperature. The pluggable nature of the modules requires dry contact thermal interfaces that permit repeated insertion–disconnect cycles under low compression pressures (∼10–100 kPa). Conventional wet thermal interface materials (TIM), such as greases, or those that require high compression pressures, are not suitable for pluggable operation. Here we demonstrate the use of compliant micro-structured TIM to enhance the thermal contact conductance between an optical module and its riding heat sink under a low compression pressure (20 kPa). The metallized and polymer-coated structures are able to accommodate the surface nonflatness and microscale roughness of the mating surface while maintaining a high effective thermal conductance across the thickness. This dry contact TIM is demonstrated to maintain reliable thermal performance after 100 plug-in and plug-out cycles while under compression.

scholarly journals A novel approach to generate non-isotropic surfaces for numerical quantification of thermal contact conductance

2021 ◽  
Vol 2116 (1) ◽  
pp. 012024
Author(s):  
Thorsten Helmig ◽  
Tim Göttlich ◽  
Reinhold Kneer
Keyword(s):  
Heat Transfer ◽  
Thermal Contact ◽  
Surface Structures ◽  
Thermal Contact Conductance ◽  
Machining Parameters ◽  
Transfer Coefficients ◽  
Contact Heat ◽  
Contact Heat Transfer ◽  
Novel Approach ◽  
Analytical Approaches

Abstract The quantification of heat flow between machine tool components is of major importance for a precise thermal prediction of the entire system. A common coupling condition between individual components is the contact heat transfer coefficient connecting the temperature field with the corresponding heat transfer at the investigated interface. However, the majority of numerical and analytical approaches assume isotropic contact surface profiles and neglect distinct surface structures caused by the manufacturing process. This assumption causes inaccuracies in the modeling as isotropic surfaces lead to an overprediction in heat transfer. Hence, this paper presents a novel approach to generate surface structures for numerical calculations considering the used machining parameters. Predicted contact heat transfer coefficients of the old as well as the new generation approach are presented and compared to experimental results offering the basis for future comprehensive investigations considering multiple parameters and materials.

A three-dimensional fractal theory based on thermal contact conductance model of rough surfaces

2017 ◽  
Vol 232 (5) ◽  
pp. 528-539 ◽  
Author(s):  
Yongsheng Zhao ◽  
Cui Fang ◽  
Ligang Cai ◽  
Zhifeng Liu
Keyword(s):  
Rough Surfaces ◽  
Fractal Theory ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Thermal Conductance ◽  
Engineering Application ◽  
Thermal Contact Conductance ◽  
Real Contact Area ◽  
Contact Conductance ◽  
Elastic Plastic

The thermal contact conductance is an important problem in the field of heat transfer. In this research, a three-dimensional fractal theory based on the thermal contact conductance model is presented. The topography of the contact surfaces was fractal featured and determined by fractal parameters. The asperities in the microscale were considered as elastic, elastic-plastic, or plastic deformations. The real contact area of the asperities could be obtained based on the Hertz contact theory. It was assumed that the rough contact surface was composed of numerous discrete and parallel microcontact cylinders. Consequently, the thermal contact conductance of the surface roughness was composed of the thermal constriction conductance of microcontacts and the air medium thermal conductance of microgaps. The thermal contact conductance of rough surfaces could be calculated by the microasperities integration. An experimental set-up with annular interface was designed to verify the presented thermal contact conductance model. Three materials were used for the thermal contact conductance analysis with different fractal dimensions D and fractal roughness parameters G. The numerical results demonstrated that the thermal contact conductance could be affected by the elastic-plastic deformation of the asperities and the gap thermal conductance should not be ignored under the lower contact load. The presented model would provide a theoretical basis for thermal transfer engineering application.

scholarly journals Thermal contact resistance across a linear heterojunction within a hybrid graphene/hexagonal boron nitride sheet

2016 ◽  
Vol 18 (35) ◽  
pp. 24164-24170 ◽  
Author(s):  
Yang Hong ◽  
Jingchao Zhang ◽  
Xiao Cheng Zeng
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Boron Nitride ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Hexagonal Boron Nitride ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Vital Role ◽  
Interfacial Thermal Conductance

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

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