Flow Regimes of a Surcharged Plunging Dropshaft-Tunnel System
Publication: Journal of Irrigation and Drainage Engineering
Volume 147, Issue 10
Abstract
In drainage and sewerage systems, vertical dropshafts are commonly used to convey water flow from high to low elevations. When the underground tunnel is surcharged, the lower part of the shaft is submerged. The impact of falling water on the free surface in the dropshaft entrains a vast amount of air, leading to the transport or entrapment of air in the tunnel, causing undesirable effects such as the reduction in flow conveyance capacity or air blowback. In this study, a comprehensive series of experiments was performed to study the influence of flow variables on the flow regimes in a submerged dropshaft connected to a horizontal tunnel. The air-water flow in the dropshaft was recorded using high-speed imaging, with air concentration and high-frequency pressure measurements. The experiments showed that the flow in the dropshaft-tunnel system can be classified into four regimes: (I) bubbly column flow, (II) rising slugs, (III) instability and surging, and (IV) net air transport in the tunnel, based on the dropshaft Froude number and the ratio of dropshaft diameter to tunnel diameter.
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Data Availability Statement
All data that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
This study is supported by the Hong Kong University of Science and Technology (HKUST) Faculty Initiation Grant (IGN17EG05) and HKUST’s Undergraduate Research Opportunities Program (UROP). The authors are in debt to the support from Dr. Q. S. Qiao and Mr. K. P. Tong in the design and fabrication of the experimental setup, and the assistance of Mr. C. H. Tong for developing the measurement equipment.
References
Banisoltan, S., N. Rajaratnam, and D. Z. Zhu. 2017. “Experimental and theoretical investigation of vertical drains withradial inflow.” J. Hydraul. Eng. 143 (5): 04016103. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001277.
Camino, G. A., N. Rajaratnam, and D. Z. Zhu. 2014. “Choking conditions inside plunging flow dropshafts.” Can. J. Civ. Eng. 41 (7): 624–632. https://doi.org/10.1139/cjce-2014-0033.
Camino, G. A., D. Z. Zhu, and N. Rajaratnam. 2015. “Flow observations in tall plunging flow dropshafts.” J. Hydraul. Eng. 141 (1): 06014020. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000939.
Chan, S. N., J. Cong, and J. H. W. Lee. 2018a. “3D numerical modeling of geyser formation by release of entrapped air from horizontal pipe into vertical shaft.” J. Hydraul. Eng. 143 (3): 04017071. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001416.
Chan, S. N., Q. S. Qiao, and J. W. H. Lee. 2018b. “On the three-dimensional flow of a stable tangential vortex intake.” J. Hydro-environ. Res. 21 (Oct): 29–42. https://doi.org/10.1016/j.jher.2018.07.001.
Chanson, H. 2004. “Hydraulics of rectangular dropshafts.” J. Irrig. Drain. Eng. 130 (6): 523–529. https://doi.org/10.1061/(ASCE)0733-9437(2004)130:6(523).
Chanson, H. 2007. “Air entrainment processes in a full-scale rectangular dropshaft at large flows.” J. Hydraul. Res. 45 (1): 43–53. https://doi.org/10.1080/00221686.2007.9521742.
Clift, R., J. R. Grace, and M. E. Weber. 1978. Bubbles, drops, and particles. New York: Academic Press.
Cong, J., S. N. Chan, and J. H. W. Lee. 2017. “Geyser formation by release of entrapped air from horizontal pipe into vertical shaft.” J. Hydraul. Eng. 143 (9): 04017039. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001332.
Crispino, G., M. Pfister, and C. Gisonni. 2019. “Hydraulic design aspects for supercritical flow in vortex drop shafts.” Urban Water J. 16 (3): 225–234. https://doi.org/10.1080/1573062X.2019.1648531.
Curtet, R., and K. Djonin. 1967. “Study of a vertical downward mixed water and air flow. Flow and concentration conditions.” Houille Blanche 53 (5): 531–550. https://doi.org/10.1051/lhb/1967038.
Davies, R. M., and G. I. Taylor. 1950. “The mechanics of large bubbles rising through extended liquids and through liquids in tubes.” Proc. R. Soc. London, Ser. A 200 (1062): 375–390. https://doi.org/10.1098/rspa.1950.0023.
Del Giudice, G., and C. Gisonni. 2011. “Vortex dropshaft retrofitting: Case of Naples city (Italy).” J. Hydraul. Res. 49 (6): 804–808. https://doi.org/10.1080/00221686.2011.622148.
Ervine, A. 1985. Two phase flow in hydraulic structures. Washington, DC: US Bureau of Reclamation.
Goldring, B. T. 1983. “Air voids at downshaft-tunnel bends.” J. Hydraul. Eng. 109 (2): 189–198. https://doi.org/10.1061/(ASCE)0733-9429(1983)109:2(189).
Gormley, M., T. J. Aspray, D. A. Kelly, and C. Rodriguez-Gil. 2017. “Pathogen cross-transmission via building sanitary plumbing systems in a full scale pilot test-rig.” PLoS One 12 (2): e0171556. https://doi.org/10.1371/journal.pone.0171556.
Himmo, S. K. M. 1986. “The behaviour of air pockets in hydraulic structures with particular reference to dropshaft/tunnel bends.” Ph.D. thesis, Dept. of Civil Engineering, Univ. of Glasgow.
Hung, H. C. K., D. W. T. Chan, L. K. C. Law, E. H. W. Chan, and E. S. W. Wong. 2006. “Industrial experience and research into the causes of SARS virus transmission in a high-rise residential housing estate in Hong Kong.” Build. Serv. Eng. Res. Technol. 27 (2): 91–102. https://doi.org/10.1191/0143624406bt145oa.
Ma, Y., D. Z. Zhu, and N. Rajaratnam. 2016. “Air entrainment in a tall plunging flow dropshaft.” J. Hydraul. Eng. 142 (10): 04016038. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001181.
Nicklin, D. J., J. O. Wilkes, and J. F. Davidson. 1962. “Two-phase flow in vertical tubes.” Trans. Inst. Chem. Eng. 40 (1): 61–67.
Padulano, R., and G. Del Giudice. 2016. “Transitional and weir flow in a vented drop shaft with a sharp-edged intake.” J. Irrig. Drain. Eng. 142 (5): 06016002. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001011.
Padulano, R., and G. Del Giudice. 2018. “Vertical drain and overflow pipes: Literature review and new experimental data.” J. Irrig. Drain. Eng. 144 (6): 04018010. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001311.
Padulano, R., G. Del Giudice, and A. Carravetta. 2013. “Experimental analysis of a vertical drop shaft.” Water 5 (3): 1380–1392. https://doi.org/10.3390/w5031380.
Pfister, M., and H. Chanson. 2012. “Discussion on ‘scale effects in physical hydraulic engineering models.’” J. Hydraul. Res. 50 (2): 244–246. https://doi.org/10.1080/00221686.2012.654671.
Pfister, M., G. Crispino, T. Fuchsmann, J. M. Ribi, and C. Gisonni. 2018. “Multiple inflow branches at supercritical-type vortex drop shaft.” J. Hydraul. Eng. 144 (11): 05018008. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001530.
Rajaratnam, N., A. Mainali, and C. Y. Hsung. 1997. “Observations on flow in vertical dropshafts in urban drainage systems.” J. Environ. Eng. 123 (5): 486–491. https://doi.org/10.1061/(ASCE)0733-9372(1997)123:5(486).
Tibke, S. W. 1982. “Air entrainment in vertical dropshafts.” Ph.D. thesis, Dept. of Building and Civil Engineering, Liverpool Polytechnic.
Viparelli, M. 1961. “Air and water currents in vertical shafts.” Houille Blanche 47 (6): 857–869. https://doi.org/10.1051/lhb/1961053.
Wallis, G. B. 1969. One-dimensional two-phase flow. New York: McGraw-Hill.
Wei, J., Y. Ma, D. Z. Zhu, and J. Zhang. 2018. “Experimental study of plunging-flow dropshafts with an internal divider for air circulation.” J. Hydraul. Eng. 144 (9): 06018011. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001510.
Whillock, A. F., and M. F. C. Thorn. 1973. Air entrainment in dropshafts. London: Construction Industry Research and Information Association.
Wijeyesekera, D. S. 1969. “Air entrainment in vertical shafts.” Ph.D. thesis, Dept. of Civil Engineering and Building Science, Univ. of Edinburgh.
Wong, K. C. 2009. “Hydraulics of bottom rack chamber for supercritical flow diversion.” M.Phil. thesis, Dept. of Civil Engineering, Univ. of Hong Kong.
Wood, I. R. 1991. Air entrainment in free surface flows: IAHR hydraulic structure design manual 4. Rotterdam, Netherlands: A.A. Balkema.
Wright, S. J., J. W. Lewis, and J. G. Vasconcelos. 2011. “Geysering in rapidly filling storm-water tunnels.” J. Hydraul. Eng. 137 (1): 112–115. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000245.
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Published In
Journal of Irrigation and Drainage Engineering
Volume 147 • Issue 10 • October 2021
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Nov 12, 2020
Accepted: May 16, 2021
Published online: Aug 12, 2021
Published in print: Oct 1, 2021
Discussion open until: Jan 12, 2022
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