An application of the wavelet analysis technique for the objective discrimination of two-phase flow patterns

作者：Nguyen Van Thai; Euh Dong Jin; Song Chul Hwa^*

来源：International Journal of Multiphase Flow, 2010, 36(9): 755-768.

DOI：10.1016/j.ijmultiphaseflow.2010.04.007

• Two-phase flow patterns
• Void fraction
• Continuous Wavelet Transform
• Local wavelet energy coefficient

This paper presents an application of the wavelet analysis technique for two-phase flow pattern identification by using the void fraction signals obtained from a multi-channel Impedance Void Meter (IVM) in a vertical-upward air-water flow. A new method for the objective discrimination of the two-phase flow pattern has been developed to provide information regarding the local energy of void fraction signals at a given scale on the joint time-frequency diagram. The void signals are processed with Continuous Wavelet Transform (CWT) to get the local wavelet energy coefficients map on the time-frequency diagram. The effective local wavelet energy and the effective scale are then calculated. Then the criteria for flow pattern identification are, finally, obtained. A series of void fraction measurements were conducted over a wide range of air-water vertical-upward flow condition to provide an extensive database to cover several types of flow patterns. The results show that the proposed method has a high precision for characterizing different flow regimes in two-phase flow, and is considerably more promising for the online recognition of two-phase flow patterns due to the short time of data processing.

• 出版日期2010-9