International Journal of Fluid Machinery and Systems

Korean Society for Fluid machinery (한국유체기계학회)
권호 표지
DOI QR코드

DOI QR Code

Unsteady Flow with Cavitation in Viscoelastic Pipes

  • Soares, Alexandre K. (Department of Sanitary and Environmental Engineering, Federal University of Mato Grosso) ;
  • Covas, Didia I.C. (Instituto Superior Tecnico, Technical University of Lisbon (TULisbon)) ;
  • Ramos, Helena M. (Instituto Superior Tecnico, Technical University of Lisbon (TULisbon)) ;
  • Reis, Luisa Fernanda R. (Sao Carlos School of Engineering, University of Sao Paulo)
  • Accepted : 2009.05.27
  • Published : 2009.12.01
Download PDF
⟨ Previous Next ⟩

Abstract

The current paper focuses on the analysis of transient cavitating flow in pressurised polyethylene pipes, which are characterized by viscoelastic rheological behaviour. A hydraulic transient solver that describes fluid transients in plastic pipes has been developed. This solver incorporates the description of dynamic effects related to the energy dissipation (unsteady friction), the rheological mechanical behaviour of the viscoelastic pipe and the cavitating pipe flow. The Discrete Vapour Cavity Model (DVCM) and the Discrete Gas Cavity Model (DGCM) have been used to describe transient cavitating flow. Such models assume that discrete air cavities are formed in fixed sections of the pipeline and consider a constant wave speed in pipe reaches between these cavities. The cavity dimension (and pressure) is allowed to grow and collapse according to the mass conservation principle. An extensive experimental programme has been carried out in an experimental set-up composed of high-density polyethylene (HDPE) pipes, assembled at Instituto Superior T$\acute{e}$cnico of Lisbon, Portugal. The experimental facility is composed of a single pipeline with a total length of 203 m and inner diameter of 44 mm. The creep function of HDPE pipes was determined by using an inverse model based on transient pressure data collected during experimental runs without cavitating flow. Transient tests were carried out by the fast closure of the ball valves located at downstream end of the pipeline for the non-cavitating flow and at upstream for the cavitating flow. Once the rheological behaviour of HDPE pipes were known, computational simulations have been run in order to describe the hydraulic behaviour of the system for the cavitating pipe flow. The calibrated transient solver is capable of accurately describing the attenuation, dispersion and shape of observed transient pressures. The effects related to the viscoelasticity of HDPE pipes and to the occurrence of vapour pressures during the transient event are discussed.

Keywords

References

  1. Almeida, A. B. and Koelle, E., 1992, Fluid Transients in Pipe Networks, Computational Mechanics Publications, Elsevier Applied Science, Southampton, UK.
  2. Wylie, E. B. and Streeter, V. L., 1993, Fluid Transients in Systems, Prentice Hall, Englewood Cliffs, N.J.
  3. Chaudhry, M. H., 1987, Applied Hydraulic Transients, Litton Educational Publishing Inc., Van Nostrand Reinhold Co, New York, USA.
  4. Zielke, W., 1968, "Frequency-dependent friction in transient pipe flow," Journal of Basic Engineering, Trans. ASME, Series D, Vol. 90, No. 1, pp. 109-115. https://doi.org/10.1115/1.3605049
  5. Covas, D., Ramos, H., Graham, N., and Maksimovic, C., 2005, "Application of hydraulic transients for leak detection in water supply systems," Water Science and Technology: Water Supply, Vol. 4, No. 5-6, pp. 365-374.
  6. Covas, D., Stoianov, I., Mano, J., Ramos, H., Graham, N., and Maksimovic, C., 2004, "The Dynamic Effect of Pipe-Wall Viscoelasticity in Hydraulic Transients. Part I - Experimental Analysis and Creep Characterization," Journal of Hydraulic Research, IAHR, Vol. 42, No. 5, pp. 516-530.
  7. Covas, D., Stoianov, I., Mano, J., Ramos, H., Graham, N., and Maksimovic, C., 2005, "The Dynamic Effect of Pipe-Wall Viscoelasticity in Hydraulic Transients. Part II - Model Development, Calibration and Verification," Journal of Hydraulic Research, IAHR, Vol. 43, No. 1, pp. 56-70. https://doi.org/10.1080/00221680509500111
  8. Ramos, H., Borga, A., Covas, D., and Loureiro, D., 2004, "Surge damping analysis in pipe systems: modelling and experiments," Journal of Hydraulic Research, IAHR, Vol. 42, No. 4, pp. 413-425. https://doi.org/10.1080/00221686.2004.9728407
  9. Martin, C. S., 1976, "Entrapped Air in Pipelines," Proc. 2nd Int. Conf. on Pressure Surges, BHRA, F2.15-F2.27.
  10. Pearsall, I. S., 1965, "The Velocity of the Water Hammer Waves," Proc. of the Institution of Mechanical Engineers, Symposium on Pressure Surges 1965-66, pp. 12-20.
  11. Covas, D., Stoianov, I., Ramos, H., Graham, N., and Maksimovic, C., 2003, "The Dissipation of Pressure Surges in Water Pipeline Systems," Pumps, Electromechanical Devices and Systems Applied to Urban Management, Vol. 2, The Netherlands, Balkema Publishers, pp. 711-719.
  12. Aklonis, J. J. and MacKnight, W. J., 1983, Introduction to Polymer Viscoelasticity, John Wiley & Sons, New York, USA.
  13. Soares, A. K., Covas, D. I. C., and Reis, L. F. R., 2008, "Analysis of PVC Pipe-Wall Viscoelasticity during Water Hammer," Journal of Hydraulic Engineering, ASCE, Vol. 134, No. 9, pp. 1389-1394. https://doi.org/10.1061/(ASCE)0733-9429(2008)134:9(1389)
  14. Bergant, A., Simpson, A. R., and Tijesseling, A., 2006, "Water Hammer with Column Separation: A Historical Review," Journal of Fluids and Structures, Vol. 22, pp. 135-171. https://doi.org/10.1016/j.jfluidstructs.2005.08.008
  15. Shu, J. J., 2003, "Modelling Vaporous Cavitation on Fluid Transients," International Journal of Pressure Vessels and Piping, Vol. 80, pp. 187-195. https://doi.org/10.1016/S0308-0161(03)00025-5
  16. Simpson, A. R. and Bergant, A., 1994, "Numerical comparison of pipe-column-separation models," Journal of Hydraulic Engineering, ASCE, Vol. 120, No. 3, pp. 361-377. https://doi.org/10.1061/(ASCE)0733-9429(1994)120:3(361)
  17. Wylie, E. B., 1984, "Simulation of vaporous and gaseous cavitation," Journal of Fluids Engineering, ASME, Vol. 106, No. 3, pp. 307-311. https://doi.org/10.1115/1.3243120
  18. Borga, A., Ramos, H., Covas, D., Dudlik, A., and Neuhaus, T., 2004, "Dynamic effects of transient flows with cavitation in pipe systems," The Practical Application of Surge Analysis for Design and Operation - 9th International Conference on Pressure Surges, Vol. 2, BHR Group Ltd., Bedfordshire, UK, pp. 605-617.
  19. Carrico, N. G., 2008, "Modelling and Experimental Analysis of Non-Conventional Dynamic Effects during Hydraulic Transients in Pressurised Systems," Master Thesis, Instituto Superior Tecnico, Technical Unviersity of Lisbon, Portugal.

Cited by

  1. Straightforward Transient-Based Approach for the Creep Function Determination in Viscoelastic Pipes vol.140, pp.12, 2014, https://doi.org/10.1061/(ASCE)HY.1943-7900.0000929
  2. Extended Bubble Cavitation Model to predict water hammer in viscoelastic pipelines vol.1101, pp.1742-6596, 2018, https://doi.org/10.1088/1742-6596/1101/1/012046
  3. Fast and accurate modelling of frictional transient pipe flow vol.98, pp.5, 2018, https://doi.org/10.1002/zamm.201600246