Online monitoring of thermal stress and heat transfer coefficient in thick-walled cylindrical elements
Autor
Taler, Jan
Taler, Dawid
Jaremkiewicz, Magdalena
Kaczmarski, Karol
Sobota, Tomasz
Smaza, Krzysztof
Opublikowane w
Archives of Thermodynamics
Numeracja
Vol. 46, No. 3,
Strony
175−186
Data wydania
2025
Wydawca
The Committee of Thermodynamics and Combustion of the Polish Academy of Sciences and The Institute of Fluid-Flow Machinery Polish Academy of Sciences
Język
angielski
ISSN
1231-0956
eISSN
2083-6023
DOI
10.24425/ather.2025.156589
Słowa kluczowe
inverse heat conduction problem, thermal stress, heat transfer coefficient, C++ Builder, visualisation
Abstrakt
The article presents a method for online monitoring of thermal stress and heat transfer coefficient on the inner surface of a thick-walled cylindrical element using two separate applications. Both applications are based on the inverse heat conduction problem and use the control volume method. The first one allows the determination of thermal stresses based on measuring the wall temperature at a single point near the inner surface. This software is suitable for one-dimensional heat transfer, i.e. in a radial direction. The second application allows the heat transfer coefficient on the inner surface to be determined based on temperature measurements at six spatially distributed points. Knowledge of the heat transfer coefficient on the inner sur face allows the stress concentration factor to be determined for elements weakened by an opening. This can be used to deter mine the optimum heating or cooling rates for pressure elements or to determine the thermal stresses in elements weakened by an opening. This method is suitable for heat transfer cases in the radial, longitudinal and circumferential directions. The correct operation of both original applications has been tested on a laboratory stand, where there was a sudden change in the working fluid temperature in a steam header from 16.8°C to 142.5°C. At the beginning of the temperature change, the thermal stresses on the header inner surface reached a maximum value of -195.8 MPa, and the heat transfer coefficient was approxi mately 5000 W/(m²K). Then, the thermal stresses began to decrease, and the heat transfer coefficient began to increase.
