Emptying of Large-Scale Pipeline by Pressurized Air

Emptying of an initially water-filled horizontal PVC pipeline driven by different upstream compressed air pressures and with different outflow restriction conditions, with motion of an air-water front through the pressurized pipeline, is investigated experimentally. Simple numerical modeling is used to interpret the results, especially the observed additional shortening of the moving full water column due to formation of a stratified water-air “tail.” Measured discharges, water-level changes, and pressure variations along the pipeline during emptying are compared using control volume (CV) model results. The CV model solutions for a nonstratified case are shown to be delayed as compared with the actual measured changes of flow rate, pressure, and water level. But by considering water-column mass loss due to the water-air tail and residual motion, the calibrated CV model yields solutions that are qualitatively in good agreement with the experimental results. A key interpretation is that the long air-cavity celerity is close to its critical value at the instant of minimum flow acceleration. The influences of driving pressure, inertia, and friction predominate, with the observed water hammer caused by the initiating downstream valve opening insignificantly influencing the water-air front propagation.

• Record URL:
  https://doi.org/10.1061/(ASCE)HY.1943-7900.0000631
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/8672558
• Supplemental Notes:
  • Copyright © 2012 American Society of Civil Engineers
• Authors:
  • Laanearu, Janek
  • Annus, Ivar
  • Koppel, Tiit
  • Bergant, Anton
  • Vuckovic, Saso
  • Hou, Qingzhi
  • Tijsseling, Arris S
  • Anderson, Alexander
  • van't Westende, Jos M C
• Publication Date: 2012-12

Language

• English

Media Info

• Media Type: Print
• Features: References;
• Pagination: pp. 1090-1100
• Serial:
  • Journal of Hydraulic Engineering
  • Volume: 138
  • Issue Number: 12
  • Publisher: American Society of Civil Engineers
  • ISSN: 0733-9429
  • Serial URL: https://ascelibrary.org/journal/jhend8

Subject/Index Terms

• TRT Terms: Air pressure; Flow resistance; Inertia (Mechanics); Polyvinyl chloride; Pressurization; Water pipelines; Water pressure; Water table
• Subject Areas: Hydraulics and Hydrology; Pipelines; I26: Water Run-off - Freeze-thaw;

Filing Info

• Accession Number: 01469545
• Record Type: Publication
• Files: TRIS, ASCE
• Created Date: Jan 17 2013 1:47PM