title: A New Statistical Parameter for Identifying the Main Transition Velocities in Bubble Columns.
abstract: The identification of the main flow regime boundaries in bubble columns is essential since the degrees of mixing and mass and heat transfer vary with the flow regime. In this work, a new statistical parameter was extracted from the time series of the cross-sectional averaged gas holdup. The measurements were performed in bubble columns by means of conductivity wire-mesh sensors at very high sampling frequency. The columns were operated with an air/deionized water system under ambient conditions. As a flow regime indicator, a new dimensionless statistical parameter called "relative maximum number of visits in a region" was introduced. This new parameter is a function of the difference between the maximum numbers of visits in a region, calculated from two different division schemes of the signal range.
authors: Helmholtz-Zentrum Dresden-Rossendorf Dresden, Germany.
authors: Stoyan
authors: S
authors: Nedeltchev
authors: Helmholtz-Zentrum Dresden-Rossendorf Dresden, Germany.
authors: Swapna
authors: S
authors: Rabha
authors: Helmholtz-Zentrum Dresden-Rossendorf Dresden, Germany; AREVA Endowed Chair of Imaging Technologies in Energy and Process Engineering, Dresden University of Technology Dresden, Germany.
authors: Uwe
authors: U
authors: Hampel
authors: Helmholtz-Zentrum Dresden-Rossendorf Dresden, Germany.
authors: Markus
authors: M
authors: Schubert
keywords: Bubble columns; Conductivity wire-mesh sensor; Flow regime identification; Gas holdup; Hydrodynamics