http://aghajar.okstate.edu/sites/default/files/pub-pdfs/Bhagwat%20%26%20Ghajar_ETFS%2039%282012%29213-227%20-%20First%20page%20only.pdf

Similarities and differences in the flow patterns and void fraction in vertical upward and downward two phase flow

Characteristics of two-dimensional waves on a falling liquid film

Wave behavior in horizontal annular air–water flow

Measuring interfacial waves on film flowing down tube inner wall using laser focus displacement meter

Experimental study and modeling of disturbance wave height of vertical annular flow

In order to clarify the effects of liquid viscosity on the interfacial structure of the flow occurring in the transition region from plug flow to annular flow regimes, time-spatial measurements of liquid holdup were carried out using liquids with kinematic viscosity of 1×10-6, 10×10-6 and 20×10-6m2 / s. Based on these measurements, time-spatial maps of wave behavior were produced and the probability distributions of wave width, wave velocity and wave height were also determined. Close inspection of these data revealed that there appeared two types of waves, namely huge waves and disturbance waves, even in cases where the liquids with the kinematic viscosity of 10×10-6 and 20×10-6m2 / s were used. Moreover, the differences between these waves became greater with an increase in the kinematic viscosity of liquid. Furthermore, it was also clarified that the region, where the gas-liquid interface was covered with ripple-like waves, became wider with an increase in the kinematic viscosity of liquid.

Effects of Liquid Viscosity on Characteristics of Waves in Gas-Liquid Two-Phase Flow (Characteristics of Huge Waves and Disturbance Waves)

Supermultiple-point-electrode conductance probe method has recently become realistic for examining the interfacial structure in gas-liquid two-phase flow. A new instrument based on this method was developed and applied into vertical downward gas-liquid two-phase flow The graphics of interfacial profiles are presented on typical flow patterns briefly and on plug and foam flows in detail. It is pointed out that the plug flow lies in the two regions separated by the foam flow, which was newly found in this study. The interfacial profiles of gas slugs depend strongly on the slip velocity of gas slug to the liquid phase in liquid slug, and the two regions of plug flow are classified into the low and high slip velocity groups. In the former group slip velocity is mostly negative Furthermore, some findings are introduced on the prediction of the void fraction in liquid slug, on its relation with the two flow regions of plug flow, and on a characteristic property observed in the fluctuation of pressure g...

Interfacial profiles and flow characteristics in vertical downward two-phase plug and foam flows

Time-series information on both the cross-sectional mean liquid holdup along a tube axis and the gas-liquid phase distribution along a tube diameter was obtained by means of supermultiple cross-sectional mean liquid holdup probes (S-CHOP) and semi-supermultiple point-electrode probes (SS-PEP) for vertical downward gas-liquid two-phase flow. Typical time-spatial behavior charts of interface and gas-liquid interfacial profiles are presented. Close inspection of these results reveals that a huge wave and a disturbance wave appear in downward two-phase flow as well as upward flow. It was clarified that the huge wave flow region covers a wide range of superficial gas velocities. Wave velocity, wave width and maximum liquid holdup of individual waves were examined by wave-vein analysis. Histograms of these flow parameters were also studied. It was found that there exist distinct differences in wave width between the huge wave and the disturbance wave. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(8): 499–510, 1996

Wave venation in downward gas‐liquid two‐phase flow (part I, time‐spatial behavior chart of interface and analysis of main wave‐vein)

PURPOSE:To accurately detect the level and film thickness of an object in a tube body by arranging a pair of electrodes, that surround the tube body, on the outside surface of the tube body, made of insulation material, with a specified interval in the direction of tube's axis. CONSTITUTION:A transparent glass tube, for example, is used as the tube body 1, and a copper wire or stainless wire, etc., is wound around it, so that electrodes 2 and 3 are formed. Between the pair of electrodes 2 and 3 arranged in the direction of the tube's axis, an electric filed is formed by electric charge, and its distribution state changes according to the liquid position 4 in the tube body 1 or film thickness 5, resulting in changes in electrostatic capacity between the electrodes 2 and 3. Since the changes in capacitance is detected as increase/ decrease in output voltage, by comparing it with a reference value measured in advance, the liquid level position 4 and film thickness 5 are detected.

Electrostatic capacitance sensor

Wave velocities and wave widths were determined using wave-vein analysis for a wide range of air and water flow rates. Cluster analysis by a K-mean algorithm was applied to the discrimination between huge and disturbance waves for the present experimental conditions. Individual waves discriminated by cluster analysis reasonably correspond to those recognized from the relation between wave velocity and wave width. Appearance flow conditions for liquid slug, huge and disturbance waves were clarified. The characteristics of wave velocity, wave width, and maximum liquid holdup for huge and disturbance waves are discussed. Comparison between liquid slug, huge wave and disturbance wave flow parameters reveals that there exist distinct differences in wave width of these waves

Wave venation in downward gas-liquid two-phase flow. (Part II, Cluster analysis for huge waves and disturbance waves and characteristics of those waves)

Koji Mori

Papers

Effects of Liquid Viscosity on Characteristics of Waves in Gas-Liquid Two-Phase Flow (Characteristics of Huge Waves and Disturbance Waves)

Interfacial profiles and flow characteristics in vertical downward two-phase plug and foam flows

Wave venation in downward gas‐liquid two‐phase flow (part I, time‐spatial behavior chart of interface and analysis of main wave‐vein)

Electrostatic capacitance sensor

Wave venation in downward gas-liquid two-phase flow. (Part II, Cluster analysis for huge waves and disturbance waves and characteristics of those waves)