PIV study of the effect of piston position on the in-cylinder swirling flow during the scavenging process in large two-stroke marine diesel engines

Sajjad Haider, Teis Schnipper, Anas Obeidat, Knud Erik Meyer, Valery Okulov, Jens Honore Walther, S. Mayer

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

A simplified model of a low speed large twostroke marine diesel engine cylinder is developed. The
effect of piston position on the in-cylinder swirling flow during the scavenging process is studied using the stereoscopic particle image velocimetry technique. The measurements are conducted at different cross-sectional planes along the cylinder length and at piston positions covering the air intake port by 0, 25, 50 and 75 %. When the intake port is fully open, the tangential velocity profile is similar to a Burgers vortex, whereas the axial velocity has a wakelike profile. Due to internal wall friction, the swirl decays downstream, and the size of the vortex core increases. For increasing port closures, the tangential velocity profile changes from a Burgers vortex to a forced vortex, and the axial velocity changes correspondingly from a wake-like profile to a jet-like profile. For piston position with 75 %
intake port closure, the jet-like axial velocity profile at a cross-sectional plane close to the intake port changes back to a wake-like profile at the adjacent downstream cross-sectional plane. This is characteristic of a vortex breakdown. The non-dimensional velocity profiles show no significant variation with the variation in Reynolds number.
Original languageEnglish
JournalJournal of Marine Science and Technology
Volume18
Issue number1
Pages (from-to)133-143
ISSN0948-4280
DOIs
Publication statusPublished - 2013

Keywords

  • Swirl
  • Scavenging
  • Two-stroke engine
  • PIV

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