Transient Flow Caused by Air Expulsion through an Orifice
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VIEW THE REPLYPublication: Journal of Hydraulic Engineering
Volume 134, Issue 9
Abstract
A pressurized water system may be subjected to high pressure surges because of the expulsion of a trapped air pocket through an orifice at the downstream end of the pipe. Results are presented of laboratory experiments, in which pressure histories were recorded for different upstream heads, air pocket volumes, and orifice sizes. The resulting pressure oscillation pattern was divided into two distinct stages: a first phase of low-frequency pressure oscillation during the air release, followed by a sudden pressure increase with water hammer characteristics when the water column reaches the orifice. The experimental results show that the duration of the first phase decreases substantially with increasing upstream head and orifice size, and increases with air pocket volume. A simple relationship was deduced, which agrees well with experimental data. The maximum pressure peaks, always observed in the water hammer phase, increased with upstream head and orifice size, whereas the volume of the air pocket appeared to be a less significant factor in the range investigated. A simple predictive equation was deduced based on Allievi–Joukowski results.
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References
Albertson, M. L., and Andrews, J. S. (1971). “Transients caused by air release.” Control of flow in closed conduits, J. P. Tullis, ed., Colorado State Univ., Fort Collins, Colo., 315–340.
Andrews, J. S. (1970). “Water hammer generated during pipeline filling.” Master’s thesis, Colorado State Univ., Fort Collins, Colo.
Benfratello, G. (1958). “Sulle sovrappressioni che si suscitano alla fine del riempimento delle tubazioni mobili.” L'Acqua, (5), 129–143 (in Italian).
De Martino, G., Gisonni, C., and Giugni, M. (2000). “Pressure surges in water mains caused by air release.” Proc., 8th Int. Conf. on Pressure Surges—Safe Design and Operation of Industrial Pipe Systems, BHR Group Conference Series Publication, Bury St. Edmunds.
De Martino, G., Giugni, M., and Viparelli, M. (1985). “La presenza dell’aria nelle condotte.” Idrotecnica, (1), 21–33 (in Italian).
De Martino, G., Giugni, M., and Viparelli, M. (1986). “Transitori in condotte idriche causati da fuoriuscita d’aria.” Idrotecnica, (2), 125–138 (in Italian).
Fanelli, M., and Reali, M. (1975). “A theoretical determination of the celerity of water hammer waves in a two-phase fluid mixture.” Energ. Elettr., (4), 186–194.
Gandenberger, W. (1957). Uber die wirtshaftliche und betriebsichere Gestaltung von Fernwasserleitungen [Design of overland water supply mains with a view to economy and operational reliability], Oldenbourg, Munich, Germany (in German).
Kolp, D. A. (1968). “Water hammer generated by air release.” Master’s thesis, Colorado State Univ., Fort Collins, Colo.
Martin, C. S. (1976). “Entrapped air in pipelines.” Proc., 2nd Int. Conf. on Pressure Surges, Paper F2, 15–28, BHRA Fluid Engineering, Bedford, England.
Martin, C. S. (1981). “Air entrainment.” Closed-conduit flow, M. H. Chaudry and V. Yevjevich, eds., Water Resources Publication, Littleton, Colo.
Martin, C. S., and Lee, N. H. (2000). “Rapid expulsion of entrapped air through an orifice.” Proc., 8th Int. Conf. on Pressure Surges—Safe Design and Operation of Industrial Pipe Systems, BHR Group Conference Series Publication, Bury St. Edmunds.
Viparelli, M., De Martino, G., and Giugni, M. (1985). “Sovrappressioni nell’efflusso da sfiati.” Quaderni dell’Accademia Pontaniana, (6), 5–55 (in Italian).
Wylie, E. B., and Streeter, V. L. (1993). Fluid transients in systems, Prentice-Hall, Englewood Cliffs, N.J.
Zhou, F., Hicks, F. E., and Steffler, P. M. (2002a). “Observation of air-water interaction in a rapidly filling horizontal pipe.” J. Hydraul. Eng., 128(6), 635–639.
Zhou, F., Hicks, F. E., and Steffler, P. M. (2002b). “Transient flow in a rapidly filling horizontal pipe containing trapped air.” J. Hydraul. Eng., 128(6), 625–634.
Zhou, F., Hicks, F. E., and Steffler, P. M. (2004). “Analysis effect of air pocket on hydraulic failure of urban drainage infrastructure.” Can. J. Civ. Eng., 31(1), 86–94.
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Information
Published In
Journal of Hydraulic Engineering
Volume 134 • Issue 9 • September 2008
Pages: 1395 - 1399
Copyright
© 2008 ASCE.
History
Received: Mar 15, 2006
Accepted: Jan 31, 2008
Published online: Sep 1, 2008
Published in print: Sep 2008
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