Thermal Conductivity of Homogeneous Materials. Determination by an Unsteady-State Method

1950 ◽  
Vol 42 (8) ◽  
pp. 1527-1532 ◽  
Author(s):  
K. O. Beatty ◽  
A. A. Armstrong ◽  
E. M. Schoenborn
Keyword(s):  
Thermal Conductivity ◽  
Unsteady State ◽  
Homogeneous Materials ◽  
State Method

AN INVERSE METHOD APPLIED TO THERMAL CONDUCTIVITY MEASURMENT OF LIGHT INSULATING MATERIALS

1995 ◽  
Vol 09 (23) ◽  
pp. 1539-1554 ◽  
Author(s):  
MICHELE CALI' ◽  
VALTER GIARETTO ◽  
GIUSEPPE RUSCICA
Keyword(s):  
Thermal Conductivity ◽  
Thermal Model ◽  
Inverse Method ◽  
Thermal Ageing ◽  
Unsteady State ◽  
Insulating Materials ◽  
Experimental Apparatus ◽  
Simplified Procedure

A simplified procedure for analyzing data obtained from an experimental apparatus in unsteady state conditions, constructed in order to measure thermal conductivity variations of light insulating materials obtained from thermal ageing and humidity cycles, is presented here. The calculations have been carried out with a lumped thermal model using an inverse method. Several ageing cycles and measurements have been carried out and the method has permitted the reduction of the experimental and calculation costs.

scholarly journals Numerical Simulation of Thermal Conductivity of Foam Glass Based on the Steady-State Method

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 54 ◽  
Author(s):  
Zipeng Qin ◽  
Gang Li ◽  
Yan Tian ◽  
Yuwei Ma ◽  
Pengfei Shen
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Heat Flow ◽  
Thermal Resistance ◽  
Thermal Insulation ◽  
Foam Glass ◽  
Orthogonal Experimental Design ◽  
Carbonate Content ◽  
Steady State Method ◽  
State Method

The effects of fly ash, sodium carbonate content, foaming temperature and foaming time on foam glass aperture sizes and their distribution were analyzed by the orthogonal experimental design. Results from the steady-state method showed a normal distribution of the number of apertures with change in average aperture, which ranges from 0.1 to 2.0 mm for more than 93% of apertures. For a given porosity, the thermal conductivity decreases with the increase of the aperture size. The apertures in the sample have obvious effects in blocking the heat flow transmission: heat flow is quickly diverted to both sides when encountered with the aperture. When the thickness of the sample is constant, the thermal resistance of the foam glass sample increases with increasing porosity, leading to better thermal insulation. Furthermore, our results suggest that the more evenly distributed and orderly arranged the apertures are in the foam glass material, the larger the thermal resistance of the material and hence, the better the thermal insulation.

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