PIV In-Cylinder Flow Measurements of Swirl and the Effect of Combustion Chamber Design

Alger, Terrence; McGee, Jeff; Gallant, Erica; Wooldridge, Steve

doi:10.4271/2004-01-1952

Cited by 7 publications

(3 citation statements)

References 10 publications

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“…The in-cylinder flow of an internal combustion (IC) engine strongly affects spark-ignition combustion and, thus, has received a considerable amount of attention from previous researchers. 2–15 In open-chamber engines, fluid enters the combustion chamber during the intake stroke and sets up a large-scale turbulent flow with structures as large as the cylinder bore. After intake valve closure (IVC), the turbulent flow decays during the ensuing compression and expansion process due to both turbulent dissipation and the viscous interaction at the walls (for open-chamber engines devoid of a piston bowl or a significant amount of tumble).…”

Section: Introductionmentioning

confidence: 99%

Size-scaling effect on the velocity field of an internal combustion engine, part II: Turbulence characteristics

Heim

Jesch

Ghandhi

2013

International Journal of Engine Research

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Top dead center turbulence characteristics in two geometrically scaled, two-valve, single-cylinder research engines were investigated to study engine size scaling relationships. Velocity data were acquired using high-magnification particle image velocimetry with different port geometries (two), different port orientations (two), and with both shrouded and nonshrouded intake valves. The data were analyzed using both an ensemble-average method and spatial-average method of defining the mean velocity field. The fluctuating velocity fields were analyzed by calculating the spatial two-point correlation functions and integrating them to find the integral length scales L 11 and L 22 and also by fitting the turbulent kinetic energy spectrum to a model energy spectrum to find the integral length scale £ and the turbulent Reynolds number Re £ . An extensive comparison between the different analysis methods was undertaken; the spatial-mean method provides more internally consistent results, in part due to the elimination of large, anisotropic structures from the analysis. The integral length scales obtained in the two engines normalized by their respective clearance heights were on average 20% larger in the large engine than in the small engine when using the ensemble-mean method, significantly less than the scale ratio (1.69), and were independent of intake port geometry. This scaling with clearance height has been anticipated, but never experimentally demonstrated. The turbulence intensity in the two engines was found to directly correlate to the mean piston speed, thus the effect of engine size on turbulence intensity is limited to its linear relation to piston speed. A given intake geometry produced the same scaling factor between turbulence intensity and mean piston speed for the two engine sizes. The turbulence intensity was found to be collapsed to a single linear relationship when plotted against a modified Mach index, which normalizes the mean piston speed with a mass-weighted flow coefficient.

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Section: Introductionmentioning

confidence: 99%

Size-scaling effect on the velocity field of an internal combustion engine, part II: Turbulence characteristics

Heim

Jesch

Ghandhi

2013

International Journal of Engine Research

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“…Particle image velocimetry (PIV) has increasingly been used in the analysis of in-cylinder flows. 7–16 PIV provides an instantaneous two-dimensional snapshot of two components of the velocity field over large cross sections of the cylinder such that bulk flow field motions can be investigated. In engines with strongly swirling flows, the in-cylinder swirl has been found to decrease approaching top dead center (TDC) due to wall friction and viscous forces acting against the motion of the large-scale structure.…”

Section: Introductionmentioning

confidence: 99%

“…In engines with strongly swirling flows, the in-cylinder swirl has been found to decrease approaching top dead center (TDC) due to wall friction and viscous forces acting against the motion of the large-scale structure. 9,12,16,17 The peak swirl is reported to occur at varying crank angles depending on engine operating conditions and measurement location. A precession of the swirl center with crank angle has also been reported.…”

Section: Introductionmentioning

confidence: 99%

Size-scaling effect on the velocity field of an internal combustion engine, part I: Bulk motion

Heim

Ghandhi

2012

International Journal of Engine Research

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In-cylinder velocity measurements were acquired to study the bulk fluid motion in two geometrically scaled, two-valve, optically accessible, and single-cylinder research engines. Different port geometries (two), different port orientations (two), and both shrouded and nonshrouded intake valves were tested to vary the intake-generated flow. The engines were motored at speeds ranging from 300 to 1200 r/min for the larger engine and from 600 to 1800 r/min for the smaller engine. Prior to testing on the engines, the different head configurations were tested on a steady flow bench. Particle image velocimetry data were taken on a single plane, parallel to the piston surface, in the engines to characterize the large-scale flow phenomena. The mean location of the swirl center and the mean angular velocity were determined by fitting a solid-body profile to the flow. The results showed that the swirl center location was relatively insensitive to engine speed for both engines, but did change position throughout the cycle. The swirl center locations, scaled by the cylinder radii, were found to be in nearly the same location for the two-scaled engines in the same nominal configuration, indicating that the swirl center motion was deterministic in nature. Normalizing the best-fit solid-body angular velocity by the engine rotation rate was found to collapse the data from the multiple engine speeds nearly onto a single curve for a given engine configuration. The angular velocity was found to decrease with crank angle due to wall friction, which was higher for the small engine because of the higher surface-to-volume ratio.

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The Effect of Fuel-Injection Timing on In-cylinder Flow and Combustion Performance in a Spark-Ignition Direct-Injection (SIDI) Engine Using Particle Image Velocimetry (PIV)

Clark

Kook

Chan

et al. 2018

Flow Turbulence Combust

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PIV In-Cylinder Flow Measurements of Swirl and the Effect of Combustion Chamber Design

Cited by 7 publications

References 10 publications

Size-scaling effect on the velocity field of an internal combustion engine, part II: Turbulence characteristics

Size-scaling effect on the velocity field of an internal combustion engine, part II: Turbulence characteristics

Size-scaling effect on the velocity field of an internal combustion engine, part I: Bulk motion

The Effect of Fuel-Injection Timing on In-cylinder Flow and Combustion Performance in a Spark-Ignition Direct-Injection (SIDI) Engine Using Particle Image Velocimetry (PIV)

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