An Experimental Technique for the Analysis of Slug Flows in Pneumatic Pipelines Using Pressure Measurements

Micromechanic modeling and analysis of the flow regimes in horizontal pneumatic conveying

“…This is in line with the experimental observations by different investigators. 2,7,69 In the stratified flow regime, a dense particle layer is formed in the lower portion of the pipe, with dunes or clusters being observed from time to time (labeled by circles in Figure 6) as experimentally reported by Tsuji and Morikawa 10 and Jama et al, 2 whereas in the upper portion of the pipe, a small number of particles are suspended in the transport gas. The dunes or clusters result in relatively large fluctuations of pressure drop and solid concentration (Figures 3d and 4d).…”

“…In addition, a pressure-drop peak and a solid-concentration peak always rise when a slug passes through the considered pipe ( Figures 3a and 4a), and a large pressure drop usually corresponds to a long slug, which agrees well with the general observations of slug flow. 7,[71][72][73] It also shows that the pressure-drop peak varies due to the unstable nature of slug flow (e.g., see Figures 4a). This is in line with the experimental observations by different investigators.…”

“…regimes. [6][7][8][9][10] In addition, a transition flow zone is identified between the slug-flow regime and the stratified flow, where conveying pipelines are very vulnerable to blockage. [11][12][13][14] Some semi theoretical correlations have also been formulated to predict the pressure drop in different flow regimes, 14,15 and the boundaries between flow regimes.…”

Axial and Radial Pressure Drops of Dense Phase Plugs

“…Although these methods have been successfully applied in laboratory tests, their application in industry has been limited either by difficulties in practical implementation or simply by cost. Li et al (2002) developed a novel experimental technique to measure various characteristics of plug flow in densephase pneumatic conveying systems. This method is based on the unique characteristics of plug flow, i.e., the fluctuation of axial pressure drop along pipelines and pressure difference in the radial direction at a plug.…”

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An experimental technique to measure various characteristics of plug flow in dense phase pneumatic conveying systems based on the unique characteristics of plug flow, i.e., the fluctuation of axial pressure drop along a pipeline and pressure difference in the radial direction at the back of a plug, was developed by Li et al (2002). Based on this work, a further experimental study combined with numerical modeling was carried out to describe the structure of plugs through the analysis of the measurements of pressure difference in both axial and radial directions.

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