<p>The narrow rectangular channel has the advantages of compact structure and high heat transfer coefficient, and has been widely used in systems such as small modular reactors. However, the internal flow of the narrow channel will be affected by the non-inertial force when it is used in undulating conditions such as marine environment. As a result, the two-phase flow signal has high nonlinearity, which makes traditional analysis methods difficult to handle with. EEMD (Ensemble Empirical Mode Decomposition) is a new type of adaptive signal time-frequency processing method based on the empirical mode decomposition. It can decompose complex signal functions into the sum of a finite number of eigenmode functions based on the local characteristic time scale of the signal itself, and is especially suitable for analyzing and processing of non-linear and non-stationary signals. Aiming at the visualized parallel narrow channel boiling experiment system, this study applies the EEMD method to the analysis of signals such as differential pressure signal between the inlet and outlet of the test section under rolling conditions. We utilize the features that the variance and energy of the empirical mode decomposition component will suddenly change in the low frequency band, and effectively realize the adaptive removal of signal noise and signal reconstruction under different rolling parameters. This paper also introduces the theory of multi-scale entropy to extract features of different time-scale signals obtained by EEMD method. The obtained signal energy moment and multi-scale entropy changes obviously with the gas-liquid distribution of the experimental section, which can be used as the basis for narrow channel flow pattern identification. &nbsp;The research in this paper shows that the EEMD-multi-scale entropy algorithm has a wide range of applications in the field of two-phase flow signal analysis.</p>

Application of Eemd-Multiscale Entropy Algorithm in the Signal Analysis of Narrow Channel Two-Phase Flow Under Rolling Motion

Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE28/volume/85246

2021 28th International Conference on Nuclear Engineering (ICONE28)

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