scholarly journals Design, Construction and Commissioning of an Apparatus for Measuring the Thermal Conductivity of Geothermal Grouting Materials Based on the Transient Hot Wire Method

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1496
Author(s):  
Carlos Castán-Fernández ◽  
Germán Marcos-Robredo ◽  
Miguel Ángel Rey-Ronco ◽  
Teresa Alonso-Sánchez
Keyword(s):  
Thermal Conductivity ◽  
Temperature Sensor ◽  
Infinite Length ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Experimental Conditions ◽  
Transient Hot Wire Method ◽  
Wire Method ◽  
Grouting Materials ◽  
Reference Samples

The aim of the present study is to develop an apparatus for the measurement of the thermal conductivity of geothermal grouting materials. The apparatus, named MCT, is designed and constructed as a direct application of a mathematical model of heat transference for conduction in an infinite homogeneous isotropic medium using a linear heat source of infinite length, infinitesimal radius and radial heat flow. This application is known as the transient hot wire method. The apparatus mainly consists of a hot wire, a power supply, a temperature sensor and a datalogger. The commissioning of the developed apparatus is carried out by means of the calibration of the temperature sensor, as well as measurements of thermal conductivity using four reference samples whose thermal conductivity is known. Each of the reference samples is formed of two solid rectangular prisms of the same material and of the same dimensions. MCT is precise and accurate. In good experimental conditions the uncertainty of the measurements is within 10%. In addition, the MCT apparatus is light and with reduced dimensions.

scholarly journals Apparatus for routine measurements of the thermal conductivity of ice cores

1999 ◽  
Vol 29 ◽  
pp. 151-154 ◽  
Author(s):  
Crescenzo Festa ◽  
Aristide Rossi
Keyword(s):  
Thermal Conductivity ◽  
Ice Cores ◽  
Maximum Temperature ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Standard Samples ◽  
Experimental Conditions ◽  
Heating Source ◽  
Central Segment ◽  
Wire Method

AbstractAn apparatus is described for measuring the thermal conductivity of ice by the transient hot-wire method. Thermal conductivity A, is determined by tracking the thermal pulse induced in the sample by a heating source consisting of a platinum resistor. A central segment of the same platinum heating resistor acts also as a thermal sensor. A heat pulse transferred to the ice for a period of 40s gives a maximum temperature increment of about 7-14°C. In good experimental conditions, the expected reproducibility of the measurements is within ±3%. The accuracy of the method depends on whether the instrument has been calibrated by reliable standard samples, certified by absolute methods.

Analysis of the Transient Hot-Wire Method to Measure Thermal Conductivity of Silica Aerogel: Influence of Wire Length, and Radiation Properties

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Ellann Cohen ◽  
Leon Glicksman
Keyword(s):  
Thermal Conductivity ◽  
Silica Aerogel ◽  
Test Method ◽  
Wire Radius ◽  
Wire Length ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
End Effects ◽  
Transient Hot Wire Method ◽  
Wire Method

When the transient hot-wire method is used to measure the thermal conductivity of very low thermal conductivity silica aerogel (in the range of 10 mW/m·K at 1 atm) end effects due to the finite wire size and radiation corrections must be considered. An approximate method is presented to account for end effects with realistic boundary conditions. The method was applied to small experimental samples of the aerogel using different wire lengths. Initial conductivity results varied with wire length. This variation was eliminated by the use of the end effect correction. The test method was validated with the NIST (National Institute of Standards and Technology) Standard Reference Material 1459, fumed silica board to within 1 mW/m·K. The aerogel is semitransparent. Due to the small wire radius and short transient, radiation heat transfer may not be fully accounted for. In a full size aerogel panel radiation will augment the phonon conduction by a larger amount.

scholarly journals A Study on Thermal Conductivity of Mixture of Magnesia Particle and Molten Nitrate by a Transient Hot Wire Method

Netsu Bussei ◽  
2005 ◽  
Vol 19 (3) ◽  
pp. 142-146 ◽  
Author(s):  
Kazuyuki Kitano ◽  
Katsuya Hanyuda ◽  
Eisyun Takegoshi ◽  
Masatoshi Sawada ◽  
Yoshio Hirasawa ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Transient Hot Wire Method ◽  
Wire Method
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