scholarly journals Guarded hot plate apparatus design and construction for thermal conductivity measurements

2021 ◽  
Author(s):  
Dave Reid
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Distribution System ◽  
Flow Distribution ◽  
Conductivity Measurement ◽  
Internal Flow ◽  
Heat Transfer Fluid ◽  
Bias Error ◽  
Hot Plate ◽  
Guarded Hot Plate

A Guarded Hot Plate (GHP) appartus was designed and built for high temperatue applications, consistent with or better than the established standards. This apparatus consists of a hot and a cold plate, attached to a frame, which allows the plates to be tilted from horizontal to vertical and configured for heating from the top to the bottom. The plates are independently heated by passing heat transfer fluid through a flow distribution system consisting of manifolds and internal flow passages, machined in each plate. Attached to the hot plate are an electrically heated heater plate and a heat flux meter, configured consistent with the hybrid method for measuring heat flux. This apparatus is designed to measure thermal conductivity of soils at different moisture contents and for temperatures ranging from -20⁰C to 200⁰C. An error analysis for the thermal conductivity measurement shows a conservative estimate of the bias error to be around [plus or minus] 2%.

scholarly journals Guarded hot plate apparatus design and construction for thermal conductivity measurements

2021 ◽  
Author(s):  
Dave Reid
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Distribution System ◽  
Flow Distribution ◽  
Conductivity Measurement ◽  
Internal Flow ◽  
Heat Transfer Fluid ◽  
Bias Error ◽  
Hot Plate ◽  
Guarded Hot Plate

A Guarded Hot Plate (GHP) appartus was designed and built for high temperatue applications, consistent with or better than the established standards. This apparatus consists of a hot and a cold plate, attached to a frame, which allows the plates to be tilted from horizontal to vertical and configured for heating from the top to the bottom. The plates are independently heated by passing heat transfer fluid through a flow distribution system consisting of manifolds and internal flow passages, machined in each plate. Attached to the hot plate are an electrically heated heater plate and a heat flux meter, configured consistent with the hybrid method for measuring heat flux. This apparatus is designed to measure thermal conductivity of soils at different moisture contents and for temperatures ranging from -20⁰C to 200⁰C. An error analysis for the thermal conductivity measurement shows a conservative estimate of the bias error to be around [plus or minus] 2%.

scholarly journals Thermal Conductivity Measurement Method for the Thin Epoxy Adhesive Joint Layer

2021 ◽  
Vol 39 (4) ◽  
pp. 402-408
Author(s):  
Da-In Lim ◽  
So-Jeong Lee ◽  
Seung-Boo Jung ◽  
Jun-Ki Kim
Keyword(s):  
Thermal Conductivity ◽  
Adhesive Joint ◽  
Conductivity Measurement ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Thermal Conductivity Measurement ◽  
Flash Method ◽  
Hot Plate ◽  
Plate Method ◽  
Guarded Hot Plate

Epoxy adhesives, particularly for non-conductive pastes, are used in 3D chip-stack flip-chip packages to reinforce the mechanical strength of joints. Although the thickness of the adhesive layer is relatively small, its thermal conductivity is known to have a major effect on the heat dissipation behavior of chipstack packages. Because conventional thermal conductivity measurement methods such as the laser flash method are based on the bulk specimens having thicknesses greater than several mm, they are limited in their ability to measure the thermal conductivity of thin adhesive layers between silicon dies. In this study, a modified guarded hot-plate method is proposed using standard joint layer samples of known thermal conductivity, and the measurement results are compared with those of the laser flash method. Results showed that, based on a constant heat flux from heat source to heat sink, the temperature difference at both sides of the joint layers was proportional to the thermal resistivity of the joint layer materials. The thermal conductivity of the under-test joint layer could therefore be determined from the thermal conductivity spectrum of the known samples using a graphical method. Although the measured values by the modified guarded hot-plate method were slightly higher than those derived from the laser flash method due to the thickness effect, it was concluded that the modified guarded hot-plate method could be a practical method in measuring the thermal conductivity of thin adhesive joint layers.

Analysis of significant measures for thermal conductivity

2020 ◽  
pp. 35-42
Author(s):  
Yuri P. Zarichnyak ◽  
Vyacheslav P. Khodunkov
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Heat Flux Density ◽  
Measurement Method ◽  
Conductivity Measurement ◽  
Surface Heat ◽  
Measuring Instrument ◽  
New Class ◽  
Achievable Accuracy

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.

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