Computer and Experimental Models of Transient Flow in a Pipe Involving Backflow Preventers
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 4
Abstract
Transient flow in a pipe was studied using both experimental and computer models. In the present study, three different numerical models: The method of characteristics model, the axisymmetrical model, and the implicit scheme model are utilized and compared. Experiments for transient flow in a simple pipeline have been conducted to verify the results from the computer models. It was found that head loss coefficient for the 1D models, such as the method of characteristics model and the implicit scheme model, should be much bigger than the Darcy-Weisbach frictional coefficient. Experiments for transient flow with the backflow preventer in a pipe were conducted. Results show that backflow preventer serves as a strong damper to the water hammer generated by the hydraulic transients. Numerical investigation simulating a backflow preventer in transient flow has been performed in this study. It was found that different values of head loss coefficient should be applied for the upstream and downstream of backflow preventer. All of the numerical models were compared with the experiments. The results of different computer models developed in the present study agree well with the experimental data.
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References
Brunone, B., Golia, U. M., and Greco, M. (1995). “Effects of two-dimensionality on pipe transients modeling.” J. Hydraul. Eng., 121(12), 906–912.
Chaudhry, H. M. (1979). Applied hydraulic transients, Van Nostrand Reinhold, New York.
Chaudhry, M. H., and Hussaini, M. Y. (1985). “Second-order accurate explicit finite-difference schemes for water-hammer analysis.” J. Fluids Eng., 107(4), 523–529.
Islam, M. R., and Chaudhry, M. H. (1998). “Modeling of constituent transport in unsteady flows in pipe networks.” J. Hydraul. Eng., 124(11), 1115–1124.
Karney, B. W. (1990). “Energy relations in transient closed-conduit flow.” J. Hydraul. Eng., 116(10), 1180–1196.
Karney, B. W., and McInnis, D. (1990). “Transient analysis of water distribution systems.” J. Am. Water Works Assoc., 82(7), 62–70.
Karney, B. W., and McInnis, D. (1992). “Efficient calculation of transient flow in simple pipe networks.” J. Hydraul. Eng., 118(7), 1014–1031.
Kwon, H. J. (2005). “Transient flow in water distribution system.” Ph.D. thesis, Univ. of Southern California, Los Angeles.
Kwon, H. J., and Lee, J. J. (2005). “The role of backflow prevention assemblies in transient flow.” ABPA News, 18(6), 13–14.
Lee, J. J., et al. (2003). “Impacts of cross-connections in North American water supplies.” Technical Rep. No. 90928, AWWA Research Foundation, Denver, Colo.
Marchi, E. (1961). “Il moto uniforme delle correnti liquide nei condotti chiusi e aperti.” Energ. Elettr., 38(4), 289–301 (in Italian).
McInnis, D., and Karney, B. W. (1995). “Transients in distribution networks: Field tests and demand models.” J. Hydraul. Eng., 121(3), 218–231.
Pezzinga, G. (1999). “Quasi-2D model for unsteady flow in pipe networks.” J. Hydraul. Eng., 125(7), 676–685.
Silva-Araya, W. F., and Chaudhry, M. H. (1997). “Computation of energy dissipation in transient flow.” J. Hydraul. Eng., 123(2), 108–115.
Simpson, A. R., and Wylie, E. B. (1991). “Large water-hammer pressures for column separation in pipelines.” J. Hydraul. Eng., 117(10), 1310–1316.
Vardy, A. E., Hwang, K. L., and Brown, J. M. B. (1993). “A weighting function model of transient turbulent pipe friction.” J. Hydraul. Res., 31, 533–548.
Watters, G. W. (1984). Analysis and control of unsteady flow in pipelines, Butterworths, Boston.
Wylie, B. E. (1983). “The microcomputer and pipeline transients.” J. Hydraul. Eng., 109(12), 1176–1194.
Wylie, B. E., and Streeter, V. L. (1993). Fluid transients in systems, FEB Press, Ann Arbor, Mich.
Zielke, W. (1968). “Frequency-dependent friction in transient pipe flow.” J. Basic Eng., 90, 109–115.
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© 2008 ASCE.
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Received: May 11, 2006
Accepted: Jun 22, 2007
Published online: Apr 1, 2008
Published in print: Apr 2008
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