نوع مقاله : مقاله پژوهشی
نویسندگان
1 بخش مهندسی مکانیک، دانشگاه تربیت مدرس
2 دانشکده مهندسی مکانیک، دانشگاه تربیت مدرس
3 دانشکده فنی و مهندسی ، گروه مکانیک، دانشگاه هرمزگان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Gas-liquid \ two-phase \ flow occurs \ frequently in \ many cases of industry, depending on the geometry of the duct, and the topography of the interface which creates different flow regimes. The Taylor bubble regime is one of the most possible patterns that exist over a wide range of gas-liquid flow rates. It is characterized by the motion of an elongated bubble among a continuous zone of liquid. The transient and intermittent nature of this regime causes sequence changes of pressure inside the channel and increases the fatigue and corrosion of the channel wall. In the present research, for its high importance, the frequency of Taylor bubbles was investigated in a large bend with three consecutive inclinations. At first, the flow regimes and flow diagrams of the inclined sections, as well as the horizontal section, in the upstream of the bend, were considered. It was noted that the Taylor bubble area stayed unchanged without the channel slope effect, and three areas were also coincident. As the bubbles merge and the bubble collapse phenomenon does not occur, the slope change of the channel does not affect the Taylor bubble frequency. A detailed explanation is given on Taylor bubble formation in the bend due to slug flow, which was generated on the upstream of the bend. The effect of gas and liquid flow rates on Taylor bubble frequency in the bend, as well as slug frequency at upstream of the bend, was also conducted in the present study. The results showed that an increase in gas flow rate decreases the Taylor bubble frequency in the whole range of liquid flow rates. In the flows with $Re_{sl}$ $$ 22000. Finally, correlations were proposed to evaluate Taylor bubble frequency, based on phase superficial Reynolds number. These correlations are important for flow regime evaluation, in addition to the lack of similar subject matter in the literature.
کلیدواژهها [English]
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