The Effect of Transfer Port Geometry on Scavenge Flow Velocities at High Engine Speed

Ekenberg, Martin; Johansson, Bengt

doi:10.4271/960366

Cited by 7 publications

(5 citation statements)

References 13 publications

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“…In a former study on the two cylinder types, laser doppler velocimetry (LDV) was used to study the incylinder flow during gas exchange [17]. The same system has also been used to measure the flow outside the exhaust port.…”

Section: Velocity Measurementsmentioning

confidence: 99%

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Crank Angle Resolved HC-Detection Using LIF in the Exhausts of Small Two-Stroke Engines Running at High Engine Speed

Andersson¹,

Juhlin²,

Ekenberg³

et al. 1996

SAE Technical Paper Series

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In order to separate the HC-emissions from two-stroke engines into short-circuit losses and emissions due to incomplete combustion, Laser Induced Fluorescence (LIF) measurements were performed on the exhaust gases just outside the exhaust ports of two engines of different designs.The difference between the two engines was the design of the transfer channels. One engine had "finger" transfer channels and one had "cup handle" transfer channels. Apart from that they were similar. The engine with "finger" transfer channels was earlier known to give more short-circuiting losses than the other engine, and that behavior was confirmed by these measurements.Generally, the results show that the emission of hydrocarbons has two peaks, one just after exhaust port opening and one late in the scavenging phase.The spectral information shows differences between the two peaks and it can be concluded that the latter peak is due to short-circuiting and the earlier due to incomplete combustion.The flow outside the exhaust port was measured with Laser Doppler Velocimetry (LDV). These measurements confirm the occurrence of two emission peaks.

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Section: Velocity Measurementsmentioning

confidence: 99%

“…The system used was a DANTEC fiber-flow with BSA signal processors. More information on the system can be found in [17].…”

Section: Velocity Measurementsmentioning

confidence: 99%

Crank Angle Resolved HC-Detection Using LIF in the Exhausts of Small Two-Stroke Engines Running at High Engine Speed

Andersson¹,

Juhlin²,

Ekenberg³

et al. 1996

SAE Technical Paper Series

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“…Laser Doppler Velocimetry measurements allowed, as reported for example in [7,8], to characterize the velocity field at the exit of intake ports of a Two-Stroke engine. This helped assessing the goodness of different intake geometries in improving SE.…”

Section: Introductionmentioning

confidence: 99%

Performance optimization of a Two-Stroke supercharged diesel engine for aircraft propulsion

Carlucci

Ficarella

Trullo

2016

Energy Conversion and Management

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“…To date, asymmetrical in-cylinder flow has been reported for a very limited range of two-stroke cycle engines. The studies that have reported asymmetrical flow fields and their adverse effects in loopscavenged two-stroke cycle engines, which were considered to be geometrically symmetrical about a nominal symmetry plane, have been published in references [1] to [7].…”

Section: Introductionmentioning

confidence: 99%

“…In 1996, Ekenberg and Johansson [7] investigated the effect of transfer duct geometry on scavenge flow velocities by making two-dimensional LDV measurements on two different cylinder designs in a fired two-stroke cycle engine at 9000 r/min. Optical access was achieved through the exhaust port.…”

Section: Introductionmentioning

confidence: 99%

Laser Doppler velocimetry measurements of flow within the cylinder of a motored tow-stroke cycle engine-comparison with some computational fluid dynamics predictions

Creaven

Fleck

Kenny

et al. 2003

International Journal of Engine Research

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This study was carried out to assess the ability of a computational fluid dynamics (CFD) code to predict the scavenging flow in the cylinder of a two-stroke cycle engine. Predictions were obtained from a CFD simulation of the flow within the cylinder. Due to the apparent sym-metry of the engine port layout, only half of the cylinder volume was modelled. Boundary conditions for the CFD model were obtained from experimentally measured pressure-time histories in the crankcase and exhaust. The two-stroke cycle engine was modified to allow laser Doppler velocimetry (LDV) measurements to be made of the in-cylinder flow. The engine was operated under motoring conditions at 500 r/min with a delivery ratio of 0.7. Although the engine scavenge port layout was geometrically symmetrical, an asymmetrical flow field was identified in the cylinder. As a result of this, a direct comparison of the in-cylinder LDV measured and CFD computed results was not possible. However, LDV and CFD results for the in-cylinder flow are presented to help highlight the dissimilarity between the measured and predicted flow fields. Two-dimensional LDV measurements were made in the cylinder at the transfer ports for a portion of the cycle. A comparison of these LDV measurements with CFD predictions of the in-cylinder velocities at the same locations showed that the CFD model could replicate reasonably well the general trend of the flow. The measured cylinder averaged turbulent kinetic energy was compared with that of the CFD model. The qualitative trend of the overall turbulence generating capacity of the engine was well replicated by the CFD model.

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The Effect of Transfer Port Geometry on Scavenge Flow Velocities at High Engine Speed

Cited by 7 publications

References 13 publications

Crank Angle Resolved HC-Detection Using LIF in the Exhausts of Small Two-Stroke Engines Running at High Engine Speed

Crank Angle Resolved HC-Detection Using LIF in the Exhausts of Small Two-Stroke Engines Running at High Engine Speed

Performance optimization of a Two-Stroke supercharged diesel engine for aircraft propulsion

Laser Doppler velocimetry measurements of flow within the cylinder of a motored tow-stroke cycle engine-comparison with some computational fluid dynamics predictions

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