Detecting regime transitions in slurry bubble columns using pressure time series

Identification of flow regime in a slurry bubble column by Hilbert-Huang transform analysis

“…The superficial gas velocity of the first regime transition point was 0.058m/s~0.069m/s, and the second regime transition point was 0.156m/s~0.178m/s. These results have similar results with Ruthiya et al [5], and they found out that the first transition point was 0.06m/s, and the second transition point was 0.12m/s in a 2D slurry bubble column. Experiments of gas-liquid two-phase flow were also carried out in the bubble column.…”

“…From Table 1, the whole energy of the heterogeneous regime (c) is the largest, and it equals to 545.14 compared with homogeneous regime (a), 60.25 and transition regime (b), 355.78. In Table 1, E 1-3 represents the low-order component, and the highfrequency section is the dominant of the energy ranges; E 7-10 represents the high-order component, and the low-frequency section is the dominant; E [4][5][6] represents the mid-frequency section. The changes on the energy distribution of IMF components show the characteristics of each flow regime.…”

“…Three types of flow patterns commonly accepted are homogeneous regime or bubbly flow regime, transition regime and heterogeneous regime or churn turbulence regime 5 . Pressure fluctuation analysis were used to identify flow regimes in some literatures [5][6][7], such as statistical analysis, fractal and chaos analysis, timefrequency analysis using wavelet transform, autocorrelation function, average cycle frequency [5]. These analysis methods are mainly utilized in gasliquid two phase flow, and more studies are needed for the analysis of three-phase flow.…”

Wide band energy analysis of fluidized bed pressure fluctuation signals using a frequency division method

“…For example, the frequency peak and the dominant frequency have been used to detect defluidization in coating and drying processes (Parise et al, 2011;de Martin et al, 2011). The coherent standard deviation and the average frequency of pressure fluctuations have also been used to estimate the bubble size and to detect the regime transitions in slurry bubble columns Ruthiya et al, 2005). Similarly, the type of the power spectrum fall-off with frequency has been used as a tool for distinguishing between deterministic and noise systems (Johnsson et al, 2000;van der Schaaf et al, 1999van der Schaaf et al, , 2004van Ommen et al, 2011;Vander Stappen, 1996).…”

Effect of particle lyophobicity in slurry bubble columns at elevated pressures

“…The solid markers are data points measured by the pressure drop method in this work. The regime transition velocities(Ruthiya et al, 2005a) are indicated by vertical lines.…”