Online monitoring of thermal loads of steam turbine components
DOI:
https://doi.org/10.24425/ather.2025.154920Abstract
The increasing share of renewable energy production in energy markets has resulted in the demand for more flexible operation of conventional power plants. Coal-fired units are forced to operate in a more cyclic duty with a higher number of starts, faster start-ups and increased load change rates. These unfavourable operating conditions result in additional thermal loading of steam turbine components and necessitate better monitoring of life-limiting components. The paper presents numerical investigations of thermal loading of a steam turbine valve at various operating conditions and identifies the requirements for an online monitoring method. A modified method based on Duhamel’s integral is proposed and validated at different transient conditions, taking into account both convection and condensation heat transfer. It was shown that the calculation method provides reasonably accurate predictions of casing wall temperature. Relative differences between measured and calculated wall temperatures are within (−2.6%)–(+1.5%) for the investigated start-ups with condensation and convection heat transfer conditions. Advantages of this method and its suitability for online monitoring of thermal loads of steam turbine components are discussed in detail.References
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