High temperature thermal diffusivity determination procedure for solids and liquids

10.2514/3.209 ◽  
1990 ◽  
Vol 4 (4) ◽  
pp. 462-468 ◽  
Author(s):  
Yildiz Bayazitoglu ◽  
P. V. R. Suryanarayana ◽  
Udaya B. Sathuvalli



1990 ◽  
Author(s):  
YILDIZ BAYAZITOGLU ◽  
P. SURYANARAYANA ◽  
UDAYA SATHUVALLI


1996 ◽  
Vol 17 (1) ◽  
pp. 253-261 ◽  
Author(s):  
Y. Maeda ◽  
H. Sagara ◽  
R. P. Tye ◽  
M. Masuda ◽  
H. Ohta ◽  
...  




Author(s):  
Yongyong Wu ◽  
Cheng Ren ◽  
Rui Li ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
...  

The effective thermal diffusivity and conductivity of pebble bed in the high temperature gas-cooled reactor (HTGR) are two vital parameters to determine the operating temperature and power in varisized reactors with the restriction of inherent safety. A high-temperature heat transfer test facility and its inverse method for processing experimental data are presented in this work. The effective thermal diffusivity as well as conductivity of pebble bed will be measured at temperature up to 1600 °C in the under-construction facility with the full-scale in radius. The inverse method gives a global optimal relationship between thermal diffusivity and temperature through those thermocouple values in the pebble bed facility, and the conductivity is obtained by conversion from diffusivity. Furthermore, the robustness and uncertainty analyses are also set forth here to illustrate the validity of the algorithm and the corresponding experiment. A brief experimental result of preliminary low-temperature test is also presented in this work.



Author(s):  
K. Elliott Cramer ◽  
William P. Winfree ◽  
Edward R. Generazio ◽  
Ramakrishna Bhatt ◽  
Dennis S. Fox ◽  
...  

Strong, tough, high temperature ceramic matrix composites are currently being developed for application in advanced heat engines. One of the most promising of these new materials is a SiC fiber-reinforced silicon nitride ceramic matrix composite (SiCf/Si3N4). The interfacial shear strength in such composites is dependant on the integrity of the fiber’s carbon coating at the fiber-matrix interface. The integrity of the carbon rich interface can be significantly reduced if the carbon is oxidized. Since the thermal diffusivity of the fiber is greater than that of the matrix material, the removal of carbon increases the contact resistance at the interface reducing the thermal diffusivity of the composite. Therefore thermal diffusivity images can be used to characterize the progression of carbon depletion and degradation of the composite. A new thermal imaging technique has been developed to provide rapid large area measurements of the thermal diffusivity perpendicular to the fiber direction in these composites. Results of diffusivity measurements will be presented for a series of SiCf/Si3N4 (reaction bonded silicon nitride) composite samples heat-treated under various conditions. Additionally, the ability of this technique to characterize damage in both ceramic and other high temperature composites will be shown.



2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060019
Author(s):  
Sidek Khasbulatov ◽  
Suleiman Kallaev ◽  
Haji Gadjiev ◽  
Zairbek Omarov ◽  
Abumuslim Bakmaev ◽  
...  

The paper presents the results of a comprehensive study of the thermophysical properties (thermal conductivity, thermal diffusivity, heat capacity) of high-temperature multiferroic BiFeO3 modified with rare-earth elements (REEs) (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu). The regularities of the formation of the mentioned characteristics were established. The assumptions about the nature of the observed phenomena were suggested.



2018 ◽  
Vol 58 (12) ◽  
pp. 2186-2190 ◽  
Author(s):  
Yuanru Yang ◽  
Hiromichi Watanabe ◽  
Mitsutoshi Ueda ◽  
Miyuki Hayashi ◽  
Masahiro Susa ◽  
...  


1978 ◽  
Vol 100 (2) ◽  
pp. 330-333 ◽  
Author(s):  
R. E. Taylor

Samples of sintered and arc-cast tungsten are available from NBS as thermal conductivity (SRM 730) and electrical resistivity (SRM 799) standards for the temperature range from 4 to 3000K. NBS recommended values for these properties above room temperature are based on results of various researchers during a previous international program which included arc-cast and sintered tungsten. The sintered tungsten used in this program was found to be unsuited for use as a standard material due to inhomogeneity and high temperature instability. The present paper gives results at high temperatures for thermal conductivity, electrical resistivity, specific heat, thermal diffusivity and Wiedemann-Franz-Lorenz ratio for a sample of the NBS sintered tungsten using the Properties Research Laboratory’s multiproperty apparatus. These results are compared to values recommended by the Thermophysical Properties Research Center, NBS, and an international program.



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