The effects of wave speed variation due to air content on the validity of similarity laws for model studies of hydraulic transients and hydraulic vibrations were investigated. Studies show that hydraulic similarities between geometrically similar model and prototype are reduced substantially for cases involving two- or three-phase flow. For flow with intensive cavitation, analysis shows that there is no hydraulic similarity between model and prototype. For pump discharge pipeline and turbine draft tube where two phase flow of air-water mixture occurs, analysis shows that the natural frequency and the response characteristics of the fluid system are a strong function of the local wave speed variation within the fluid system. This local wave speed variation is a function of the local transient air content and transient pressure.

Issue Section:
Research Papers
Topics:
Hydraulic transients, Vibration, Waves, Engineering prototypes, Flow (Dynamics), Fluids, Transients (Dynamics), Cavitation, Pipelines, Pressure, Pumps, Turbines, Two-phase flow, Water
1.
Brown, F. T., 1968, “A Quasi Method of Characteristics with Application to Fluid Lines with Frequency Dependent Wall Shear and Heat Transfer,” ASME Journal of Basic Engineering, pp. 217–227.
2.
Ewing, D. J. F., 1980, “Allowing for Free Air in Waterhammer Analysis,” Proc. Third Int. Conf. Pressure Surges, Canterbury, England, BHRA, pp. 80–91.
3.
Jemcov, R., Krsmanovic, L., and Pejovic, S., 1980, “Excitations of Vibrations in Pumped Storage Power Plant ‘Chaplaina,’ (in Serbo-Croatian),” JUG EL, Ljubljana, pp. 443–495.
4.
Jonsson, L., 1985, “Maximum Transient Pressures in a Conduit with Check Valve and Air Entertainment,” Int Conf. on the Hydraulics of Pumping Stations, University of Manchester Inst of Sci and Tech (UMIST) & BHRA, England, pp. 55–76.
5.
Lee
T. S.
,
1991
, “
Numerical Computation of Fluid Pressure Transients in Pumping Installations with Air Entrainment
,”
International Journal for Numerical Methods in Fluids
, Vol.
12
, pp.
747
–
763
.
6.
Lee
T. S.
,
1994
, “
Numerical Modelling and Computation of Fluid Pressure Transients with Air Entrainment in Pumping Installations
,”
International Journal for Numerical Methods in Fluids
, Vol.
19
, pp.
89
–
103
.
7.
Lee
T. S.
,
1995
, “
Numerical Studies on Effects of Check Valve Performance on Pressure Surges During Pump Trip in Pumping System with Air Entrainment
,”
International Journal for Numerical Methods in Fluids
, Vol.
21
, pp.
337
–
348
.
8.
Pejovic, S., Boldy, A. P., and Obradovic, D., 1987, Guidelines to Hydraulic Transient Analysis, Technical Press, England.
9.
Pejovic, S., 1989, “Similarity in Hydraulic Vibrations of Power Plants,” Joint ASCE/ASME Int Conference on Fluids Machinery, San Diego, pp. 5–11.
10.
Pejovic, S., 1990, “Similarity of Hydraulic Transients,” Pressure Surges-Proceedings of 6th Int Conf., BHAR, pp. 221–232.
11.
Pejovic, S., and Boldy, A. P., 1992, Guidelines to Hydraulic Transient Analysis of Pumping Systems, P&B Press, Belgrade—Coventry, England.
12.
Pejovic, S., Dunn, A., and Lai, C. K., 1993, “Machine Influence Stability and Response to Hydraulic Oscillations,” Proceedings, IAHR Working Group on the Hydraulic Machineries under Steady Oscillatory Conditions, Lausane, pp. 30–36.
13.
Pejovic, S., Dunn, A., and Lai, C. K., 1994, “Pump Influence on Hydraulic Vibrations and Stability in Laboratory and Reality,” Proc. IAHR 17th Symposium, Beijing, Oct., pp. 1–6.
14.
Perko, H. D., 1984, “Gasausscheidung in Instationarer Rohrstromung,” Dissertation, University of Hannover, Institute for Fluid Mechanics.
15.
Provoost, G. A., 1976, “Investigation into Cavitation in a Prototype Pipeline caused by Waterhammer,” Proc. 2nd Int Conf. on Pressures, Bedford, England, BHRA, pp. 35–43.
16.
Whiteman, K. J., and Pearsall, I. S., 1959, “Reflux Valve and Surge Tests at Kingston Pumping Station,” Brit. Hydromech. Res. Asoc/National Engineering Laboratory Joint Report No 1.
17.
Wylie, B. E., and Sweeter, L. V., 1993, Fluid Transients, Prentice-Hall, Englewood Cliffs, NJ.
This content is only available via PDF.
Copyright © 1996
 by The American Society of Mechanical Engineers
You do not currently have access to this content.