Multiphase Science and Technology A Quarterly

ISSN for PRINT: 0276-1459

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Best Paper Award Selection - Editorial Board Site

2006, Volume18

Issue 1

114 pages

DOI: 10.1615/MultScienTechn.v18.i1

Issue price - $150.00

Mamoru Ishii
Therma-Hydraulics and Reactor Safety Laboratory, School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907, USA

X. Sun
Therma-Hydraulics and Reactor Safety Laboratory, School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907; Department of Mechanical Engineering, The Ohio State University, 650 Ackerman Road, Columbus, OH 43202, USA

This paper presents new experimental and modeling approaches in characterizing interfacial structures in gas-liquid two-phase flow. For the experiments, two objective approaches are developed to identify flow regimes and to obtain local interfacial structure data. First, a global measurement technique using a non-intrusive ring-type impedance void-meter and a self-organizing neural network is presented to identify the “one-dimensional” flow regimes. In the application of this measurement technique, two methods are discussed, namely, one based on utilizing various statistical moments of the probability density function of the impedance probe's signal (PDF input method) and the other based on the sorted impedance signals, which is essentially the cumulative probability distribution function of the impedance signals (instantaneous direct signal input method). In the latter method, the identification can be made almost instantaneously since the required signals can be acquired over a very short time period. In addition, a double-sensor conductivity probe can also be used to obtain “local” flow regimes by using the instantaneous direct signal input method with the bubble chord length information. Furthermore, a newly designed conductivity probe with multiple double-sensor heads is proposed to obtain “two-dimensional” flow regimes across the flow channel. Secondly, a state-of-the-art four-sensor conductivity probe technique has been developed to obtain detailed local interfacial structure information. The four-sensor conductivity probe accommodates the double-sensor probe capability and can be applied in a wide range of flow regimes spanning from bubbly to churn-turbulent flows. The signal processing scheme is developed such that it categorizes the acquired parameters into two groups based on bubble cord length information. Furthermore, for the modeling of the interfacial structure characterization, the interfacial area transport equation proposed earlier has been studied to provide a dynamic and mechanistic prediction tool for two-phase flow analysis. Based on detailed modeling of the bubble interactions, one-group and two-group interfacial area transport equations have been developed.

DOI: 10.1615/MultScienTechn.v18.i1.10 Download article, 1-29 pages

Article price - $45.00

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