scholarly journals A Measurement Method of Thermal Conductivity of Soft Materials and Liquids by Utilizing a Point-Contact Method

Netsu Bussei ◽  
2014 ◽  
Vol 26 (3) ◽  
pp. 136-141 ◽  
Author(s):  
Takahiro OKABE ◽  
Hiroshi MASHIMO ◽  
Junnosuke OKAJIMA ◽  
Atsuki KOMIYA ◽  
Ichiro TAKAHASHI ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Measurement Method ◽  
Point Contact ◽  
Soft Materials ◽  
Contact Method

scholarly journals Thermophysical properties of some liquid binary Mg-based alloys

2017 ◽  
Vol 53 (3) ◽  
pp. 279-284
Author(s):  
Y. Plevachuk ◽  
V. Sklyarchuk ◽  
G. Pottlacher ◽  
A. Yakymovych ◽  
O. Tkach
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Thermoelectric Power ◽  
Thermophysical Properties ◽  
Point Contact ◽  
Calculated Data ◽  
Contact Method ◽  
Concentric Cylinder ◽  
Cast Alloys ◽  
Cylinder Method

In this study, some structure-sensitive thermophysical properties, namely, electrical conductivity, thermal conductivity and thermoelectric power of liquid binary alloys Al33.3Mg66.7, Mg47.6Zn52.4 and Mg33.3Zn66.7 (all in wt.%), as the most promising cast alloys to fabricate components for cars, aircraft and other complex engineering products, were investigated. The electrical conductivity and thermoelectric power were measured in a wide temperature range by the four-point contact method. The thermal conductivity was measured by the steady-state concentric cylinder method. The obtained results are compared with literature experimental and calculated data.

scholarly journals The liquid AlCu4TiMg alloy: thermophysical and thermodynamic properties

2020 ◽  
Vol 49 (1-2) ◽  
pp. 61-73
Author(s):  
YURIY PLEVACHUK ◽  
VASYL SKLYARCHUK ◽  
GERNOT POTTLACHER ◽  
THOMAS LEITNER ◽  
PETER ŠVEC SR. ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Tension ◽  
Thermoelectric Power ◽  
Pure Aluminum ◽  
Point Contact ◽  
Calculated Data ◽  
Electromagnetic Levitation ◽  
Contact Method ◽  
Concentric Cylinder ◽  
Cylinder Method

In this study, some structure-sensitive thermophysical properties, namely, thermal conductivity, thermoelectric power, density and surface tension of liquid AlCu4TiMg alloy, as one of the most promising cast alloys to fabricate components for cars, aircraft and other complex engineering products, were investigated. Thermoelectric power was measured in a wide temperature range by the four-point contact method. Thermal conductivity was investigated by the steady-state concentric cylinder method. The oscillating drop technique combined with electromagnetic levitation was used for density and surface tension studies. The results obtained are compared with experimental and calculated data from literature for pure aluminum.

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.

Design of a Steady-State, Parallel-Plate Thermal Conductivity Apparatus for Nanofluids and Comparative Measurements With Transient HWTC Apparatus

2010 ◽  
Author(s):  
Milivoje M. Kostic ◽  
Casey J. Walleck
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Parallel Plate ◽  
Measurement Method ◽  
Mixture Theory ◽  
Hot Wire ◽  
Electro Magnetic ◽  
Magnetic Phenomena ◽  
Thermal Conductivities

A steady-state, parallel-plate thermal conductivity (PPTC) apparatus has been developed and used for comparative measurements of complex POLY-nanofluids, in order to compare results with the corresponding measurements using the transient, hotwire thermal conductivity (HWTC) apparatus. The related measurements in the literature, mostly with HWTC method, have been inconsistent and with measured thermal conductivities far beyond prediction using the well-known mixture theory. The objective was to check out if existing and well-established HWTC method might have some unknown issues while measuring TC of complex nano-mixture suspensions, like electro-magnetic phenomena, undetectable hot-wire vibrations, and others. These initial and limited measurements have shown considerable difference between the two methods, where the TC enhancements measured with PPTC apparatus were about three times smaller than with HWTC apparatus, the former data being much closer to the mixture theory prediction. However, the influence of measurement method is not conclusive since it has been observed that the complex nano-mixture suspensions were very unstable during the lengthy steady-state measurements as compared to rather quick transient HWTC method. The nanofluid suspension instability might be the main reason for very inconsistent results in the literature. It is necessary to expend investigation with more stable nano-mixture suspensions.

Wheel-Rail Multi-Point Contact Method for Railway Turnouts

2011 ◽  
Vol 97-98 ◽  
pp. 378-381
Author(s):  
Zhi Wei Chen ◽  
Linan Li ◽  
Shi Gang Sun ◽  
Jun Long Zhou
Keyword(s):  
Calculation Method ◽  
Normal Force ◽  
Contact Point ◽  
Point Contact ◽  
Contact Model ◽  
Contact Method ◽  
Elastic Contact ◽  
Simulation Calculation ◽  
Acute Change

A calculation method of wheel-rail multi-point contact based on the elastic contact model is introduced. Moreover, the simulation calculation of vehicles passing through branch lines of No.18 turnouts is carried out. The result showed that the acute change of wheel-rail normal force caused by the transfers of wheel-rail contact point between two rails can be avoid by wheel-rail multi-point contact method, and the transfers of wheel-rail normal force between two rails is smoother. The validity of wheel-rail multi-point contact method is verified.

Simulations of Fully-Flexible Fuel Bundle Response due to Turbulence Excitation

2019 ◽  
Author(s):  
Osama Elbanhawy ◽  
Marwan Hassan ◽  
Atef Mohany
Keyword(s):  
Numerical Model ◽  
Single Point ◽  
Point Contact ◽  
Vibration Response ◽  
Pressure Tube ◽  
Contact Method ◽  
Impact Forces ◽  
Fuel Bundle ◽  
System Components ◽  
Fuel Elements

Abstract This work presents a numerical model for a fully-flexible CANDU fuel bundle to predict the vibration response due to turbulence excitation. The model includes 37 fuel elements and two endplates. The contact between system components such as fuel-to-fuel and fuel-to-pressure tube is modeled using the single point contact method (SPC). A range of flow velocities was examined, and the associated impact forces and work rates were calculated. In addition, the stresses on the endplates due to vibration of the fuel elements were predicted.

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