ESTONIAN ACADEMY
PUBLISHERS
eesti teaduste
akadeemia kirjastus
PUBLISHED
SINCE 1952
 
Proceeding cover
proceedings
of the estonian academy of sciences
ISSN 1736-7530 (Electronic)
ISSN 1736-6046 (Print)
Impact Factor (2021): 1.024
Water-column mass losses during the emptying of a large-scale pipeline by pressurized air; pp. 8–16
PDF | doi: 10.3176/proc.2015.1.02

Authors
Janek Laanearu, Qingzhi Hou, Ivar Annus, Arris s. Tijsseling
Abstract

In many industrial applications the liquid trapped inside long pipelines can cause a number of problems. Intrusion of the pressurized air on top of the water column inside the horizontal pipeline can result in a less or more mixed stratified flow. The dynamics of a moving air–water front during the emptying of a PVC pipeline with the diameter-to-length ratio 1 : 1100 were experimentally and theoretically studied. In the experiments, the water was driven out of the pipeline with an initial upstream air pressure of 2 barg and a 4.5 m high downstream-end siphon, where the water outflow was restricted by a valve that was closed 11%. The measured discharges and water-level variations are analysed together with Control Volume modelling results. During the ‘forced’ (not only gravity-driven) emptying process, both the downstream-end drainage and tail leakage behind the moving air–water front decreased over the full water-column length. The water-column mass loss due to the tail leakage is referred to as holdup. The Zukoski dimensionless number is used to parameterize the relative shortening of the water column associated with the unidirectional movement of the air–water front along the large-scale horizontal test section of the pipeline, where surface-tension effects and minor losses at joints and turns are negligible.

References

Benjamin, T. B. 1968. Gravity currents and related phen­omena. J. Fluid Mech., 31(2), 209–248.
http://dx.doi.org/10.1017/S0022112068000133

Bergant, A. and Simpson, A. R. 1999. Pipeline column separa­tion flow regimes. ASCE J. Hydraul. Eng., 125(8), 835–848.
http://dx.doi.org/10.1061/(ASCE)0733-9429(1999)125:8(835)

Bergant, A., Simpson, A. R., and Tijsseling, A. S. 2006. Water-hammer with column separation: a historical review. J. Fluid Struct., 22(1), 135–171.
http://dx.doi.org/10.1016/j.jfluidstructs.2005.08.008

Bergant, A., van ’t Westende, J. M. C., Koppel, T., Gale, J., Hou, Q., Pandula, Z., and Tijsseling, A. S. 2010. Water hammer and column separation due to accidental simultaneous closure of control valves in a large scale two-phase flow experimental test rig. In Proceedings of the ASME 2010 Pressure Vessels & Piping Division/K-PVP Conference. Bellevue, Washing­ton, USA. Paper PVP2010–26131, Vol. 3, pp. 923–932.

Bergant, A., Hou, Q., Keramat, A., and Tijsseling, A. S. 2011. Experimental and numerical analysis of water hammer in a large-scale PVC pipeline apparatus. In Proceed­ings of the 4th IAHR International Meeting on Cavita­tion and Dynamic Problems in Hydraulic Machinery and Systems (Belgrade, Serbia, October 2011), pp. 27–36.

Bozkus, Z. and Wiggert, D. C. 1997. Liquid slug motion in a voided line. J. Fluid Struct., 11(8), 947–963.
http://dx.doi.org/10.1006/jfls.1997.0112

Collins, R. P., Boxall, J. B., Karney, B. W., Brunone, B., and Meniconi, S. 2012. How severe can transients be after a sudden depressurization? J. Am. Water Works Ass., 104(4), E243–E251.
http://dx.doi.org/10.5942/jawwa.2012.104.0055

Hou, Q., Tijsseling, A. S., Laanearu, J., Annus, I., Koppel, T., Bergant, A., Vučkovič, S., Gale, J., Anderson, A., van ’t Westende, J. M. C., Pandula, Z., and Rup­recht, A. 2012. Experimental Study of Filling and Emptying of a Large-scale Pipeline. External Report, CASA Report No. 12-15. Technische Universiteit Eindhoven, Eindhoven.

Hou, Q., Tijsseling, A. S., Laanearu, J., Annus, I., Koppel, T., Bergant, A., Vučkovič, S., Anderson, A., and van ’t Westende, J. M. C. 2014. Experimental investi­ga­tion on rapid filling of a large-scale pipeline. ASCE J. Hydraul. Eng., 140(11), 04014053.
http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0000914

Laanearu, J. and van ’t Westende, J. 2010. Hydraulic charac­teristics of test rig used in filling and emptying experiments of large-scale pipeline. In Proceedings of the Hydralab III Joint Transnational Access User Meeting, Hannover, 2–4 February 2010. Coastal Research Centre FZK of Leibniz University and Technical University of Braunschweig, Hannover, Germany, pp. 5–8.

Laanearu, J., Annus, I., Koppel, T., Bergant, A., Vučkovič, S., Hou, Q., Tijsseling, A. S., Anderson, A., and van ’t Westende, J. M. C. 2012. Emptying of large-scale pipeline by pressurized air. ASCE J. Hydraul. Eng., 138(12), 1090–1100.
http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0000631

Laanearu, J., Annus, I., Sergejeva, M., and Koppel, T. 2014. Semi-empirical method for estimation of energy losses in a large-scale pipeline. Procedia Engineering, 70, 969–977.
http://dx.doi.org/10.1016/j.proeng.2014.02.108

Martin, C. S. and Lee, N. 2012. Measurement and rigid column analysis of expulsion of entrapped air from a horizontal pipe with an exit orifice. In Proceedings of the 11th International Conference on Pressure Surges. BHR Group, Lisbon, Portugal, pp. 527–542.

Martinoia, T., Barreto, C. V., da Rocha, J. C. D. C., Lavoura, J., and Henriques, F. M. P. 2012. Simulation and planning of pipeline emptying operations. In Proceedings of the 9th International Pipeline Con­ference. ASME, Calgary, Alberta, Canada, Paper No. IPC2012-90432, pp. 603–611.

Pozos, O., Gonzalez, C. A., Giesecke, J., Marx, W., and Rodal, E. A. 2010. Air entrapped in gravity pipeline systems. J. Hydraul. Res., IAHR, 48(3), 338–347.
http://dx.doi.org/10.1080/00221686.2010.481839

Tijsseling, A. S., Hou, Q., and Bozkus, Z. 2014. An improved 1D model for liquid slugs travelling in pipelines. In Proceedings of the ASME 2014 Pressure Vessels & Piping Division Conference, Anaheim, California, USA. PVP2014–28693.

Zukoski, E. E. 1966. Influence of viscosity, surface tension, and inclination angle on motion of long bubbles in closed tubes. J. Fluid Mech., 25(4), 821–837.
http://dx.doi.org/10.1017/S0022112066000442

Back to Issue