Viscosity and Thermal Conductivity of Dry Air in the Gaseous Phase

1985 ◽  
Vol 14 (4) ◽  
pp. 947-970 ◽  
Author(s):  
K. Kadoya ◽  
N. Matsunaga ◽  
A. Nagashima
Keyword(s):  
Thermal Conductivity ◽  
Gaseous Phase ◽  
Dry Air

scholarly journals Conduction of heat through powders and its dependence on the pressure and conductivity of the gaseous phase

1926 ◽  
Vol 113 (764) ◽  
pp. 459-477 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Thermal Conductivity ◽  
Gaseous Phase ◽  
Linear Relation ◽  
Gas Pressure ◽  
Pumice Stone ◽  
Solid Part ◽  
Thermal Conductivities

The object of our investigation has been to study the conduction of heat through a light powder and to find how it depends upon the pressure and thermal conductivity of the gas in which the powder is immersed. A solution of this question is part of the solution of the problem of the conduction of heat through a certain class of “solid” heat insulators—a class which includes those of lowest thermal conductivity. The class of insulator referred to are solids dispersed in gases, or gases dispersed in solids, and consists of three kinds of substances, (1) fibrous substances ( e.g., wool, eiderdown, asbestos), (2) cellular substances (e. g., cork, pumice stone) and (3) powders (e. g., lamp-black, powdered cork, silox or monox). It might be expected that substances so different as those mentioned would have very different thermal conductivities. Actually their conductivities range from about 8 to 11 times 10 -5 cal. cm. -1 deg. -1 sec. -1 . As there is nothing common to the solid part of these substances, their conductivities, it would seem probable, are determined mainly by the factor which is common to them all, that is, the gaseous part, which is air. Our experiments have been made with a very light powder known as monox or silox, and the conductivity of this powder when immersed in air, in carbon dioxide, and in hydrogen at various pressures has been determined. We find that there is a linear relation between the conductivity of the powder and the logarithm of the pressure of the gas in which it is immersed, so that if k is the measure of the conductivity of the powder, k 0 that of the gas in which it is immersed, and p the measure of the gas pressure, then k = ½ k 0 log 10 p/n approximately, where n is a constant for a given gas.

scholarly journals Effective Thermal Conductivity of a Wet Porous Medium—Presence of Hysteresis When Modeling the Spatial Water Distribution for the Pendular Regime

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Édouard Canot ◽  
Renaud Delannay ◽  
Salwa Mansour ◽  
Mohamad Muhieddine ◽  
Ramiro March
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Water Distribution ◽  
Thermal Flux ◽  
Liquid Volume ◽  
Liquid Meniscus ◽  
Dry Air ◽  
Different Shapes ◽  
Spherical Grains ◽  
Water Meniscus

This paper deals with the heat transfer between two spherical grains separated by a small gap; dry air is located around the grains and a liquid water meniscus is supposed to be present between them. This problem can be seen as a microscale cell of an assembly of solid grains, for which we are looking for the effective thermal conductivity. For a fixed contact angle and according to the volume of the liquid meniscus, two different shapes are possible for the meniscus, giving a “contacting” state (when the liquid makes a true bridge between the two spheres) and a “noncontacting” one (when the liquid is split in two different drops, separated by a thin air layer); the transition between these two states occurs at different times when increasing or decreasing the liquid volume, thus leading to a hysteresis behavior when computing the thermal flux across the domain.

Thermal conductivity of some deuterated compounds in the gaseous phase

1974 ◽  
Vol 27 (2) ◽  
pp. 978-981 ◽  
Author(s):  
N. B. Vargaftik ◽  
N. A. Vanicheva
Keyword(s):  
Thermal Conductivity ◽  
Gaseous Phase

Thermal conductivity of CD3OH, CH3OH, C2D6, C2H6 in the gaseous phase

1979 ◽  
Vol 37 (3) ◽  
pp. 1071-1073 ◽  
Author(s):  
L. V. Yakush ◽  
N. A. Vanicheva ◽  
L. S. Zaitseva
Keyword(s):  
Thermal Conductivity ◽  
Gaseous Phase

scholarly journals CALCULATION OF THE THERMAL CONDUCTIVITY OF POROUS MEDIA

1958 ◽  
Vol 36 (7) ◽  
pp. 815-823 ◽  
Author(s):  
William Woodside
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Approximate Equation ◽  
Spherical Particles ◽  
Insulating Materials ◽  
Cubic Lattice ◽  
Dry Air ◽  
Thermal Insulating ◽  
Experimental Values ◽  
Good Agreement

The problem of determining the effective thermal conductivities of porous and other composite materials from the conductivities and volume fractious of their constituents is examined. An approximate equation is derived for the case of a cubic lattice of identical spherical particles in a medium having properties different from those of the particles. This equation is applied to the calculation of the thermal conductivity of snow at different densities in the range 0.10 to 0.48 gm/cc. The effect of water vapor diffusion in snow under a temperature gradient is taken into account by adding a latent heat term to the conductivity value for dry air. Conductivity values for snow, calculated in this manner, are found to agree satisfactorily with experimental data. An equation due to Russell is also shown to give conductivity values for several cellular thermal insulating materials which are in good agreement with experimental values.

Experimental study of thermal conductivity in lithium in the gaseous phase at high temperatures

1988 ◽  
Vol 55 (6) ◽  
pp. 1400-1405 ◽  
Author(s):  
N. B. Vargaftik ◽  
Yu. K. Vinogradov ◽  
Yu. K. Yakimovich
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
High Temperatures ◽  
Gaseous Phase
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