Simplified Approach for the Optimal Sizing of Throttled Air Chambers
Publication: Journal of Hydraulic Engineering
Volume 138, Issue 12
Abstract
Among water hammer damping devices, air chambers are often used in pumping plants to reduce pressure surges to acceptable values. The chamber is more effective if a throttling device is used, resulting in a reduction of the required volume. Design charts for a simple and fast sizing of air volume and orifice diameter are available in the literature using the rigid column theory (incompressible flow) and the De Sparre rule. Nevertheless, in many cases the pressure pattern is far from being constant during the first quarter of the transient period and lower pressures can be attained; furthermore, the rigid column model is not able to reproduce elastic phenomena arising from throttling, and so water hammer equations should be used instead. Although orifice induced pressure waves are evident only in the first part of the transient, differences between air chamber pressure and pipe pressure can be quite significant. Negative pressure surge should be limited because column separation and cavitation could occur as a consequence of low pressures. Because the maximum down surge inferred from the design charts does not ensure safe design, a simplified approach was proposed in this paper to design throttled air chambers under the elastic hypothesis. The analysis showed small deviations between the minimum pressure and the design pressure, unlike the inelastic approach, which exhibits even very large differences with water hammer equations.
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References
Calame, J., and Gaden, D. (1926). Théories des Chambres D’Equilibre, Dunod, Paris, 271 (in French).
Camichel, C. (1917). “Sur le calcul des grandes surpressions dans les conduites munies d’un réservoir d’air.” C. R. de l’Ac. des Sc, 164(Jan–Jun), 331–333 (in French).
De Martino, G., De Paola, F., Fontana, N., and Giugni, M. (2004). “Discussion of ‘Simple guide for design of air vessel for water hammer protection of pumping lines’ by D. Stephenson.” J. Hydraul. Eng., 130(3), 273–275.
De Martino, G., and Fontana, N. (2010). “La verifica del transitorio nelle casse d’aria con resistenza localizzata.” L’Acqua, (6), 45–52 (in Italian).
De Sparre, M. (1911a). “Des coups de bélier dans les conduites.” La Houille Blanche, (10), 257–263 (in French).
De Sparre, M. (1911b). “Des coups de bélier dans les conduites.” La Houille Blanche, (11), 293–298 (in French).
Di Santo, A., Fratino, U., Iacobellis, V., and Piccinni, A. F. (2002). “Effects of free outflow in rising mains with air chamber.” J. Hydraul. Eng., 128(11), 992–1001.
Evangelisti, G. (1935a). “L’impiego delle camere d’aria per attenuare i colpi d’ariete nelle condotte elevatorie.” L’Elettrotecnica, 22(4), 251–255 (in Italian).
Evangelisti, G. (1935b). “Sul calcolo delle oscillazioni di carico nelle condotte degli impianti di sollevamento.” L’Elettrotecnica, 22(6), 390–394 (in Italian).
Evangelisti, G. (1938). “Il colpo d’ariete nelle condotte elevatorie munite di camera d’aria.” L’Energia Elettrica, 15(9), 600–613 (in Italian).
Fok, A. K. (1978). “Design charts for air chamber on pump pipe lines.” J. Hydr. Div., 104(9), 1289–1303.
Graze, H. R., and Horlacher, H. B. (1986). “Design charts for throttled (by-pass) air chambers.” Proc., 5th Int. Conf. on Pressure Surges, Hannover, BHRA, Cranfield, U.K., 309–322.
Larock, B. E., Jeppson, R. W., and Watters, G. Z. (2000). Hydraulics of pipeline systems, CRC, Boca Raton, FL.
Malekpour, A., and Karney, B. W. (2011). “Rapid filling analysis of pipelines with undulating profiles by the method of characteristics.” ISRN Appl. Math., 16.
Modica, C., and Pezzinga, G. (1989). “L’effetto della strozzatura sui transitori negli impianti elevatori muniti di cassa d’aria.” L’Energia Elettrica, 66(11), 507–518 (in Italian).
Paoletti, A. (1972). “Il transitorio negli impianti elevatori muniti di casse d’aria.” L’Energia Elettrica, 49(6), 370–383 (in Italian).
Parmakian, J. (1963). Waterhammer analysis, Dover Publications, New York.
Ruus, E. (1980). “Discussion on ‘Design charts for air chamber on pump pipe lines’ by A. B. Almeida and J. Hipolito.” J. Hydr. Div., 106(9), 1525–1526.
Sarpkaya, T. (1962). “Unsteady flow of fluids in closed systems.” J. Eng. Mech. Div., 88(EM3), 1–15.
Stephenson, D. (2002). “Simple guide for design of air vessels for water hammer protection of pumping lines.” J. Hydraul. Eng., 128(8), 792–797.
Streeter, V. L., and Wylie, E. B. (1978). Fluid transients, McGraw-Hill, New York.
Thorley, A. R. D., and Enever, K. J. (1979). “Control and suppression of pressure surges in pipelines and tunnels.”, London, U.K., 112.
Wood, D. J. (1970). “Pressure surge attenuation utilizing an air chamber.” J. Hydr. Div., 96(5), 1143–1156.
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© 2012 American Society of Civil Engineers.
History
Received: Oct 4, 2011
Accepted: May 11, 2012
Published online: May 15, 2012
Published in print: Dec 1, 2012
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