Effects of Free Outflow in Rising Mains with Air Chamber
Publication: Journal of Hydraulic Engineering
Volume 128, Issue 11
Abstract
Air chamber design is usually accomplished by the use of charts or numerical models based on the classic boundary condition of a constant-level downstream reservoir. However, a constant-level downstream reservoir typically does not exist in currently operating facilities. The downstream end of the rising main is usually designed with the outlet at a level above the maximum allowed in the receiving reservoir. Such a scheme is usually chosen in order to avoid the loss of stored water in case of leakage or breakdown of the pipeline. For this reason, the final section of the discharge pipeline is often fitted with a vertical pipe with free outflow. This particular downstream condition influences the transient state that occurs following a power failure in the pump. In this paper, we focus on the variations of maximum and minimum pressures and water-level oscillations that arise in the terminal section of the rising main, by means of complete transient analysis. The rigid water column model is used to provide design charts for preliminary design. A numerical investigation using dimensionless parameters is performed to investigate the system behavior within the significant ranges of system-characteristic quantities. Field experiments were performed on a pump–pipeline discharge system located in a water supply system in southern Italy. The recorded pressure traces are compared with results obtained from a model that accounts for this particular downstream boundary condition.
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References
Allievi, L.(1937). “Air chamber for discharge lines.” Trans. ASME, 59, 651–659.
Carron, A.(1986). “Un diagnostic de coup de bélier établi par modèle numeriqué.” Houille Blanche, 1/2, 120–126 (in French).
Chaudhry, M. H. (1987). Applied hydraulic transients, 2nd Ed., Van Nostrand Reinhold, New York.
Clarke, D. S. (1985). “Surge suppression—A warning.” Proc., Int. Conf. on the Hydraulics of Pumping Stations, Manchester, U.K., 39–54.
Di Santo, A., Fratino, U., and Piccinni A. F. (1994). “Influenza della condizione di valle nel proporzionamento delle casse d’arie al servizio degli impianti elevatori.” Proc., Seminario sul moto vario nei sistemi acquedottistici, Bari, Politecnico di Bari (in Italian).
Evangelisti, G.(1938). “Il colpo d’ariete nelle condotte elevatorie munite di camere d’aria.” Energ. Elettr., 15, 600–613 (in Italian).
Evans, W. E., and Crawford, C. C.(1954). “Design charts for air chambers on pump lines.” Trans. Am. Soc. Civ. Eng., 119, 1025–1045.
Fiori, G. L., Giuliani, A., Gulletta, G., Iacobellis, V., and Piccinni, A. F. (1994). “Rilievi sperimentali di moto vario su un impianto di sollevamento munito di cassa d’aria.” Proc., Seminario sul moto vario nei sistemi acquedottistici, Bari, Politecnico di Bari (in Italian).
Fok, A. T. K.(1978). “Design charts for air chambers on pump pipe lines.” J. Hydraul. Div., Am. Soc. Civ. Eng., 9, 1289–1303.
Fratino, U., and Iacobellis, V. (1997). “La validità dell’ipotesi anelastica nello studio degli impianti di sollevamento con cassa d’aria aventi sezione terminale ad efflusso libero.” Proc., Giornate di studio in onore del Prof. E. Orabona nel centenario della nascita, Bari, Politecnico di Bari (in Italian).
Graze, H. R.(1971). “Discussion of ‘Pressure surge attenuation utilizing an air chamber’ by Don J. Wood.” J. Hydraul. Div., Am. Soc. Civ. Eng., 3, 455–459.
Idelchik, I. E. (1994), Handbook of hydraulic resistance, 3rd Ed., CRC, Boca Raton, Fla., 222.
Jönsson, L. (1985). “Maximum transient pressures in a conduit with check valve and air entrainment.” Proc., Int. Conf. on the Hydraulics of Pumping Stations, Manchester, U.K., 55–76.
Kruisbrink, C. S. W., Lavooij, C., and Koetzier, H. (1986). “Dynamic behavior of large nonreturn valves.” Proc., 5th Int. Conf. on Pressure Surges, Hannover (D).
Lee, T. S.(1998). “A numerical method for the computation of the effects of an air vessel on the pressure surges in pumping systems with air entrainment.” Int. J. Numer. Methods Fluids, 28, 703–718.
Milano, V., Sassoli, F., and Todini, E.(1974). “Simulazione mediante il ‘Continuous simulation modeling program’ di un modello matematico di transitorio in un impianto elevatorio munito di camera d’aria.” Energ. Elettr., 6, 325–331 (in Italian).
Modica, C., and Pezzinga, G.(1989). “L’effetto della strozzatura sui transitori negli impianti elevatori muniti di cassa d’aria.” Energ. Elettr., 11, 507–518 (in Italian).
Modica, C., and Pezzinga, G.(1990). “Su un dispositivo mobile di strozzatura alla base di casse d’aria.” Energ. Elettr., 12, 507–530 (in Italian).
Paoletti, A.(1972). “Il transitorio negli impianti elevatori muniti di casse d’aria.” Energ. Elettr., 6, 370–383 (in Italian).
Paynter, H. M.(1971). “Discussion of ‘Design charts for air chambers on pump lines’ by W. E. Evans and C. C. Crawford.” Trans. Am. Soc. Civ. Eng., 119, 1039–1045.
Popescu, M. (1985). “Highly efficient protection system against waterhammer for pumping stations.” Proc., Int. Conf. on the Hydraulics of Pumping Stations, Manchester, U.K., 77–88.
Purcell, J. P.(1997). “Case study of check valve slam in rising main protected by air vessel.” J. Hydraul. Eng., 123(12), 1166–1168.
Purcell, J. P.(1999). “Closure to ‘Case study of check valve slam in rising main protected by air vessel.’” J. Hydraul. Eng., 125(5), 551–552.
Rao, P. V., Achar, K. R. T., and Rao, P. L. N.(1999). “Discussion of ‘Case study of check valve slam in rising main protected by air vessel’ by P. Veerabhadra Rao.” J. Hydraul. Eng., 125(5), 550–551.
Thorley, A. R. D., and Lastowiecki, P. (1985). “Air vessel design for rising mains.” Proc., Int. Conf. on the Hydraulics of Pumping Stations, Manchester, U.K., 89–98.
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Copyright © 2002 American Society of Civil Engineers.
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Received: Aug 9, 2000
Accepted: May 1, 2002
Published online: Oct 15, 2002
Published in print: Nov 2002
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