Study of Slug Flow in Horizontal, Inclined, and Vertical Pipes
In the literature several mathematical models have been reported for the slug flow, which uses the concept of the unit slug in common. This concept requires the longitudes of the liquid slug and the Taylor bubble to be known, for the correct evaluation of
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Abstract In the literature several mathematical models have been reported for the slug flow, which uses the concept of the unit slug in common. This concept requires the longitudes of the liquid slug and the Taylor bubble to be known, for the correct evaluation of the terms: phase-wall and interfacial shear stresses, and virtual mass forces. In this work are presented the results of an experimental study of the upward slug flow (in an acrylic pipe with 6 m of length and 0.01905 m of internal diameter). The working fluids are water and air. They were carried out experiments for several angles of tube inclination from horizontal to vertical. The length of liquid slug and Taylor bubble were measured. Also, using voltage signals of two infrared sensors, was determined: (1) The Taylor bubble velocity by means of the cross correlation and (2) The slug frequency when applying the Fourier transform to these obtained data; this information allows to determine the length of liquid slug. It was observed that the Taylor bubble length decreases when increasing the flow of the liquid so much as the angle of inclination, while the Slug length varies with a similar tendency.
O. C. Benítez-Centeno (&) O. Cazarez-Candia Instituto Tecnológico de Zacatepec, Calzada del Tecnológico No. 27 Zacatepec, 62780 Morelos, MEX, Mexico e-mail: [email protected] O. Cazarez-Candia e-mail: [email protected] O. Cazarez-Candia Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152 Col San Bartolo Atepehuacan, 07730 Mexico, D.F., Mexico
J. Klapp et al. (eds.), Fluid Dynamics in Physics, Engineering and Environmental Applications, Environmental Science and Engineering, DOI: 10.1007/978-3-642-27723-8_18, Ó Springer-Verlag Berlin Heidelberg 2013
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O. C. Benítez-Centeno and O. Cazarez-Candia
1 Introduction When proposing mathematical models to represent in a realistic way the slug flow, in the literature, diverse positions are presented (mechanistics, slug tracking or slug capturing) where the concept of the unit slug is used, when solving this models numerically the stresses phase-wall and interfacial forces should be calculated, the above mentioned implies to know the lengths of the liquid slug and the Taylor bubble just as it is appreciated in the Eqs. (1) and (2). Where s is the stress, the sub index k denotes the phase (l liquid or g gas) that has contact with the wall ðwÞ, Ug is the phase gas velocity, al is the liquid fraction, ql is the density of the liquid, FVM is the virtual mass force, CVM is the virtual mass coefficient, DH is the hydraulic diameter, Db and LTB they are respectively the diameter and the length of the Taylor bubble, LLS is the slug length and finally LSU is the unit slug length. " # ðslugÞ ðTaylor BubbleÞ skw skw LLS LTB skw ¼ þ ð1Þ DHk LSU DHk LSU
oUg oUg oUl oUl þ Ug þ Ul ot ox ot ox 2 0 13 1 LDb TB A5 ¼ 540:66 þ 0:34@ 1 3LDbTB
FVM ¼ CVM ð1 al Þql
CVM
ð2Þ
ð3Þ
Having appropriate values for LLS y LTB , has an impact to obtain better predictions of pressure drop when mechani
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