PIV Measurements in the Swirl-Plane of a Motored Light-Duty Diesel Engine

SAE 2011 World Congress & Exhibition
Authors Abstract
Particle image velocimetry (PIV) is used to investigate the structure and evolution of the mean velocity field in the swirl (r-θ) plane of a motored, optically accessible diesel engine with a typical production combustion chamber geometry under motoring conditions (no fuel injection). Instantaneous velocities were measured were made at three swirl-plane heights (3 mm, 10 mm and 18 mm below the firedeck) and three swirl ratios (2.2, 3.5 and 4.5) over a range of crank angles in the compression and expansion strokes. The data allow for a direct analysis of the structures within the ensemble mean flow field, the in-cylinder swirl ratio, and the radial profile of the tangential velocity. At all three swirl ratios, the ensemble mean velocity field contains a single dominant swirl flow structure that is tilted with respect to the cylinder axis. The axis of this structure precesses about the cylinder axis in a manner that is largely insensitive to swirl ratio. Higher swirl ratios reduce the cycle-to-cycle variability in the orientation of this structure. The tangential velocity profiles are well represented by the Bessel function profile often used to initialize the tangential velocity in CFD codes. A value of 2.2 is recommended for the value of the parameter α which controls the shape of the Bessel function profile. During the compression stroke, the measured in-cylinder swirl ratios were similar to those determined from steady-state flow bench measurements. The swirl ratios decreased significantly after TDC, and continued to decline during the expansion stroke.
Meta TagsDetails
Petersen, B., and Miles, P., "PIV Measurements in the Swirl-Plane of a Motored Light-Duty Diesel Engine," SAE Int. J. Engines 4(1):1623-1641, 2011, https://doi.org/10.4271/2011-01-1285.
Additional Details
Apr 12, 2011
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Journal Article