Fluctuating Characteristics of Two-Phase Air-Water Slug Flow in Pressurized Pipelines

Document Type : Research Paper

Author

Assist. Prof., Civil Eng. Dept., Isfahan Univ. of Technology

Abstract

Two-phase gas-liquid flows occur in a wide variety of situations, e.g., in chemical processing, power generation, water supply systems, and petroleum industry. The study of two-phase fluid flows is of great importance in hydraulic engineering. This type of flow typically occurs in pressurized flow tunnels, culverts, siphons, and bends in which the gas trapped in water pipelines releases from the water as the pressure reduces. The relative discharge rate of fluids and the pipe slope produce a wide variety of flow patterns including stratified, wavy, and slug flows. In this paper, the unstable two-phase air-water flow is experimentally investigated. The image processing technique is applied for estimating the fluctuations of such parameters as void fraction and length, period and celerity of slug waves. It is shown that the pipe inclination and air flow rate have significant effects on flow characteristics. Also, the relative wave length (L/D, D is the pipe diameter) in a slug flow varies from 10 to 85, while air bubble length varies from 1/3 to 1/2 of wave length.

Keywords

References

1- Falvey, H. T. (1980). Air-water flow in hydraulic structures, Eng. Monograph, No. 41, US Department of the Intrior, Water and Power Resources Service.
2- Lockhart, R. W., and Martinelli, R. C. (1949). “Proposed correlation of data for isothermal two-phase two-component flow in pipes.” Chem. Eng. Prog,  64 (193), 39-48.
3- Holley, E. R. (1969). “Surging in laboratory pipeline with steady inflow.” ASCE, J. Hydr. Eng., 95 (3), 961-979.
4- Albertson, M. L., and Andrews, J.S. (1971). Transients caused by air release, in control of flow in closed conduits, (J.P.Tullis, ed.), Colorado State University, Fort Collins, Colorado.
5- Martin, C.S. (1976). “Entrapped air in pipelines.” Proc. of the Second International Conference on Pressure Surges, BHRA Fluid Engineering, Cranfiled, Bedford, London, England.
6- Hamam, M. A., and McCorquodale, J. A. (1982). “Transient conditions in the transition from gravity to surcharged sewer flow.” Canadian J. of Civil Engineering, 9 (2), 189-196.
7- Cardle, J. A., Song, C. C. S., and Yuan, M. (1989). “Measure of mixed transient flows.”
J. Hydr. Eng. ASCE, 115 (2), 169-185.
8- Li, J., and McCorquodale, J. A. (1999). “Modeling mixed flow in storm sewers.” J. of Hydraulic Engineering, 125 (11), 1170-1179.
9- Zhou, F., Hicks, F., and Steffler, P. (2002). “Transient flow in rapidly filling horizontal pipe containing trapped air.” J. Hydraulic Engrg, 128 (6), 635-639.
10- Zhou, F., Hicks, F., and Stefller, P. (2002). “Observation of air-water interaction in a rapidly filling horizontal pipe.” J. Hydr. Eng., 128 (6), 635-639.
11- Issa, R. I., and Kempf, M. H. W. (2003). “Simulation of slug flow in horizontal and nearly horizontal pipes with the two-fluid model.” Int. J. Multiphase Flow, 29, 69-95.
12- Kabiri-Samani, A. R., Borghei, S. M., and Saidi, M. H. (2007). “Fluctuation of air-water two-phase flow in horizontal and inclined water pipelines.” J. of Fluid Eng., ASME, 129 (1), 1-14.
13- Seleghim, P. J., and Hervieu, E. (1998). “Direct imaging of two-phase flows by electrical impedance measurements.” IOP Pub., Meas. Sci. Tech., 9, 1492-1500.
14- Dong, F., Liu, X., Deng, X., Xu, L., and Xu, L. A. (2001). “Identification of two-phase flow regimes in horizontal, inclined and vertical pipes.” I.O.P., Meas. Sci. Tech., 12, 1069-1075.
15- Azzopardi, B. J., and Baker, G. (2003). “Characteristics of periodic structure in gas/liquid two-phase flow.” Proc. UK/Japan Two-Phase Flow Meeting, Guildford, UK.
16- Aimable, R., and Zech, Y. (2003). “Experimental results on transient and intermittent flows in a sewer pipe model.” XXX IAHR Cong., Theme B, AUTH, Thessaloniki, Greece, 377-384.
17- Wang, S. F., Ozawa, M., and Shoji, M. (2003). Fluctuation of gas-liquid two-phase flow through an impacting T-junction, Research Program Report, Sasakawa Scientific Research, Japan Science Society, Japan.
Journal of Water and Wastewater; Ab va Fazilab ( in persian )
Volume 20, Issue 2 - Serial Number 2
Serial number:70
May and June 2009
Pages 62-68

Files

Share

How to cite

Statistics