| Autor: |
CARMI, RAMI, BUSSIBA, ARIE, WIDENFELD, GALIT, AHARON, YOSI, ALON, IGAL, HOCHBAUM, IGAL |
| Předmět: |
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| Zdroj: |
Journal of Acoustic Emission; Jan-Dec2011, Vol. 29, p89-97, 9p |
| Abstrakt: |
The capability to predict parameters and to develop quantitative predictive models in sub-cooled boiling flow is considerable importance to nuclear reactor safety and in many other industrial processes. Such predictions are based on heat transfer mechanisms derived from theoretical models and from experimental data on bubble dynamics from growth and motion aspects. In practice, it is essential to predict the complete boiling curve in system with specific conditions, which performs an accurate description of the boiling process, and to point out the transition between the regions. The prediction of the boiling curve is based on temperature measurements on the surface of the heating element using thermocouples or thermographic and high speed cameras [1, 2]. The accuracy of these measurements could be improved by applying acoustic emission (AE) method especially in complicated geometries. The current study adopts the AE techniques in order to examine the potential of the AE in detection of bubbles during boiling process and to point out the transition zones. Preliminary AE work has been conducted in order to determine the appropriate AE parameters, and to eliminate mechanical and electromagnetic interferences. The AE findings in terms of counts, amplitude, peak frequency, etc., as a function of the applied current, revealed the early stages of bubble formation during boiling process. The AE data also indicates the transition between the different regions of the boiling curve. The AE results were analyzed by spectrum analysis and wavelet analysis in order to determine characteristic frequencies and sequences of the water boiling processes. The AE results show a great potential to detect in situ the early stages of boiling process and can be used as an efficient tool for monitoring continuously possible boiling in industrial pipes where the boiling might be critical and damage process. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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