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Radiation effects in the transient hot-wire technique

Measurement of the thermal conductivity of n -pentane

Journal of Thermal Analysis and Calorimetry
Authors: Y. Shi, L. Sun, J. Venart, and R. Prasad

Abstract  

The transient hot-wire technique is widely used for absolute measurements of the thermal conductivity and thermal diffusivity of fluids. It is well established that fluid radiation effects significantly influence these measurements, especially those for the thermal diffusivity. Corrections for radiation effects are based on the models developed and deviations of the measured data from the ideal line source model. In this paper, the effect of fluid radiation on the measurements of the thermal conductivity of n-pentane is presented. For comparison, the influence of thermal radiation effect on measurement of transparent fluids, such as argon is also shown. The difference between the influence of natural convection and thermal radiation is also demonstrated.

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), Numerical simulation of heat transfer by natural convection in cavities of facade elements . Energy and Buildings , 35 ( 3 ), 305 – 311 . [11] White F. M

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Fluid radiation effects in the transient hot-wire technique

Measurement of thermal conductivity of propane

Journal of Thermal Analysis and Calorimetry
Authors: Y. Shi, L. Sun, F. Tian, J. Venart, and R. Prasad

Abstract  

The transient hot-wire technique is widely used for absolute measurements of the thermal conductivity of fluids. Refinement of this method has resulted in a capability for accurate and simultaneous measurement of both thermal conductivity and thermal diffusivity together with a determination of the specific heat. However, these measurements, especially those for the thermal diffusivity, may be significantly influenced by fluid radiation. The present work investigates the effect of fluid radiation on the measurements of the thermal conductivity of propane. Recently developed corrections have been used to examine this assumption and rectify the influence of even weak fluid radiation. Measurements at 372 K with a hot-wire instrument demonstrate the presence of radiation effects in both the liquid and vapor phase. The influence is much more pronounced in liquid propane at 15.5 MPa than in the vapor phase at 881.5 kPa. The technique employed to obtain radiation-free thermal conductivity measurements is described.

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Journal of Thermal Analysis and Calorimetry
Authors: Benigno Barbés, Ricardo Páramo, Francisco Sobrón, Eduardo Blanco, and Carlos Casanova

absence of natural convection, as will be justified later. The first aim of this article has been to develop a suitable model of the experimental cell to justify the equation which expresses the thermal conductivity of a liquid sample in function

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. [3] Awbi H. B. Calculation of convective heat transfer coefficients of room surfaces for natural convection , Energy Build , Vol. 28 , No. 2

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] Khalifa A. J. N. ( 2001 ), Natural convective heat transfer coefficient: a review I . Isolated vertical and horizontal surfaces. Energy Conversion and Management. 42 , 491 – 504 . [14

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on their operating principle. 2.1 Passive cooling methods The first group is passive cooling solutions, which can be used to cool cells without the need for additional energy. The most common solutions are operating with the natural convection of the

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Pollack Periodica
Authors: Gábor Rózsás, György Bognár, Gábor Takács, and Balázs Plesz

on their operating principle. 2.1 Passive cooling methods The first group is passive cooling solutions, which can be used to cool cells without the need for additional energy. The most common solutions are operating with the natural convection of the

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, circulation can be noted in the figures except for inclination angle of 45° because the velocity of liquid phase is relatively small. Further, the strengths of the natural convection, caused by the warm and cool liquids, are relatively very weaker for 45° than

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Schladow, S. G., M. Lee, B. E. Herzeler and P. B. Kelly. 2002. Oxygen transfer across the air-water interface by natural convection in lakes. Limnol. Oceanogr. 47: 1394–1404. Kelly P. B

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