Experimental and analytical investigation into boiling induced thermal stress: Its impact on the stress state of oxide scales of nuclear components
| Autor: | Satbyoul Jung, Maolong Liu, Hyungdae Kim, Youho Lee |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Nuclear and High Energy Physics
Materials science 020209 energy Mechanical Engineering Bubble Nucleation Oxide 02 engineering and technology 01 natural sciences 010305 fluids & plasmas Stress (mechanics) chemistry.chemical_compound Nuclear Energy and Engineering Heat flux chemistry Boiling 0103 physical sciences Thermal 0202 electrical engineering electronic engineering information engineering General Materials Science Composite material Safety Risk Reliability and Quality Waste Management and Disposal Nucleate boiling |
| Zdroj: | Nuclear Engineering and Design. 341:66-72 |
| ISSN: | 0029-5493 |
| Popis: | This paper experimentally and theoretically investigates thermal stress of materials caused by non-uniform surface temperature fields due to bubble dynamics of nucleate boiling. The surface temperature of Calcium fluoride (CaF2) on a thin-film indium tin oxide (ITO) heater was measured by an Infrared high-speed camera. Then, the obtained temperature fields were used to calculate boiling induced thermal stresses. An analytical model was developed to predict thermal stress due to nucleate boiling. The localized cold spot under a growing bubble gives rise to the peak tensile stress. The magnitude of the peak stress is predominantly determined by liquid and solid properties, and applied heat flux to a limited extent. Nevertheless, higher heat flux is observed to result in a higher probability of material fracture due to an increased number of nucleation sites, which gives a larger effective surface area under stress. Newly discussing another cause of stresses for oxide layer mechanical integrity, the presented discovery of boiling induced stress implies potential effects on break-away of oxide scales under boiling conditions, including reactor fuel claddings and steam generator U-tubes. Moreover, the boiling stress can be potentially used to design self-cleaning surfaces by breaking unwanted deposits. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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