Effects of large-scale turbulence on cyclic variability in spark-ignition engine

Burluka, Alexey; Hussin, A. M. T. A. Eldein; Ling, Zhengyang; Sheppard, C. G. W.

doi:10.1016/j.expthermflusci.2012.04.012

Cited by 24 publications

(38 citation statements)

References 10 publications

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“…Their measurements showed that the heat flux of the first cycle was not only higher during the compression stroke, but also during the expansion stroke. This indicates that the turbulence and gas motion caused by the induction process persists throughout the entire engine cycle, being confirmed 150 by recent investigations of Burluka et al [28] in an optically accessible engine.…”

Section: Influence Of Intake Flowsupporting

confidence: 69%

Heat transfer in premixed spark ignition engines part I: Identification of the factors influencing heat transfer

Broekaert

Demuynck

Cuyper

et al. 2016

Energy

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The heat transfer from the combustion gases to the cylinder walls inside a spark ignition engine is a key factor in an engine's design, due to its influence on the engine's efficiency, power and emissions. Therefore a lot of research has been conducted in order to accurately model the heat transfer, for engine design and optimization purposes. These models have been found to provide inaccurate predictions for fuels which have significantly different gas properties compared to traditional fossil fuels. This indicates that the models either do not properly include gas properties, or are missing some important properties in their formulation. In order to construct a general ("fuel-independent") heat transfer model, new measurements need to be executed, with multiple fuels that have different properties. Designing such an experiment requires a thorough understanding of the factors influencing the heat transfer and their interactions. In this paper a literature review is presented of heat transfer measurements in spark ignition engines in order to investigate the effect of the engine factors on the heat transfer. Based on this review, a root cause analysis is conducted to identify the independent factors that affect heat transfer. These factors are then used to set up two experiments according to a Design of Experiments methodology that allows the investigation of the effect of different gas properties and engine settings on the heat transfer in a consistent way. The results of these measurements for motored operation are discussed in [1] and for fired operation in a companion paper [2].

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Section: Influence Of Intake Flowsupporting

confidence: 69%

Heat transfer in premixed spark ignition engines part I: Identification of the factors influencing heat transfer

Broekaert

Demuynck

Cuyper

et al. 2016

Energy

View full text Add to dashboard Cite

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“…When the respective filtered data were used in the analysis, the insensitivity to compression ratio was even stronger and a lack of clear proportionality with the clearance height before and after TDC was obvious. The analysis was expanded to more lateral integral length scales in [65] A recent study in a similar bore disk-shaped chamber to that of [63][64][65] but without swirl and a compression ratio of 10.6 [78] measured integral length scales by PIV on a horizontal plane at 17 °CA BTDC for 1500 RPM, 1 bar intake. These were found to be 6-8 mm for the longitudinal correlation of both u and w and about 4-5 mm for the lateral correlation.…”

Section: Comparison Of Integral Length Scales With Other Engines and mentioning

confidence: 99%

Integral Length Scales and Time Scales of Turbulence in an Optical Spark-Ignition Engine

Aleiferis

Behringer

Malcolm

2016

Flow Turbulence Combust

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In-cylinder air flow structures are known to play a major role in mixture preparation and flame development in spark-ignition engines. In this paper both LDV and PIV measurements were undertaken in an optical spark-ignition at 1500 RPM, 0.5 bar inlet plenum pressure. One of the primary PIV planes was vertical, cutting through the centrally located spark plug (tumble plane) inside the pentroof at ignition timing. The other plane was horizontal inside the pentroof 1 mm below the spark plug. LDV was conducted 1 mm below the spark plug on a line from inlet to exhaust but also on a lower line 14 mm below the spark plug. In-cylinder PIV data at specific crank angles in the intake and compression strokes were also analysed on the central tumble plane and on a horizontal plane 14 mm below the spark plug. The combination of both techniques allowed high spatial and temporal resolution as the two data sets complemented each other to provide details of mean flow and turbulence characteristics on different levels, aiming ultimately for quantification of integral time scales and length scales. LDV cycle-resolved analysis distinguished between the classic approach of using the time integral of the autocorrelation function to obtain the integral time scale and a high-frequency cut-off analysis to obtain high-and low-frequency fluctuations about an in-cycle mean.3

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“…Understanding the incylinder air flow is of great importance for DISI engines because it is inherently coupled to mixture formation via spray-flow interactions. Although early Particle Image Velocimetry (PIV) studies on engine flows had highlighted the issue of bias in the statistical analysis of small batches of engine cycles [1,2], data storage issues and processing time have forced most researchers to use no more than 50-200 cycles for their analysis [3][4][5][6]. More recently kHz range high-speed PIV has been utilised for typical 2D flow mapping but also with volume-based characterisation that can be used for validation of Large Eddy Simulation (LES) of engine flows [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Modulation of integral length scales of turbulence in an optical SI engine by direct injection of gasoline, iso -octane, ethanol and butanol fuels

Aleiferis

Behringer

2017

Fuel

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In-cylinder air flow structures are known to play a major role in mixture preparation and engine operating limits for spark-ignition engines. In this paper PIV measurements were undertaken in an optical spark-ignition at 1500 RPM, part-load with 0.5 bar intake plenum pressure. One of the PIV planes was vertical, cutting through the centrally located spark plug (tumble plane). The other plane was horizontal 1 mm below the spark plug ground electrode (swirl plane). The effect of engine head temperature was also examined by using engine-head coolant temperatures of 20 °C and 80 °C. The flow field was examined late in the compression stroke at typical ignition timing. The study was conducted under air-only motoring engine conditions but also under fuelled conditions in the early intake stroke using direct injection of gasoline, iso-octane, ethanol and butanol fuels. The flow field under air-only motored conditions showed velocities between 3-5 m/s predominantly from intake to exhaust. Little differences were observed between hot and cold engine-head temperature; typically ~10% larger mean velocity and turbulent kinetic energy was seen on the intake side. Integral length scales were on the tumble plane between 2-4.5 mm in the vertical and 4-7 mm in the horizontal direction. The swirl view showed scales between 4-10 mm, larger at cold than at hot engine-head conditions. The vertical length scales appeared to be limited by the clearance height, scaling typically by about 10-15%. The horizontal components scaled to the cylinder bore diameter by about 5-12%. The fuel injection process in the early intake stroke led to little differences in the general mean flow structure at ignition timing, except for a small increase in the maximum velocities, ~10%. The turbulent kinetic on the tumble plane was highest towards the exhaust side of the engine under non-fuelled engine conditions but fuel injection resulted in highest values on the intake side. The integral length scales with fuel injection were of the same order of magnitude to those of air only measurements on the tumble plane, but showed distinctly larger areas with length scales up to 9 mm on the swirl plane. Differences between fuels for their fuel specific injection duration were small, with average length scales between 4-6 mm. Ethanol exhibited typically largest scales and butanol smallest.3

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Effects of large-scale turbulence on cyclic variability in spark-ignition engine

Cited by 24 publications

References 10 publications

Heat transfer in premixed spark ignition engines part I: Identification of the factors influencing heat transfer

Heat transfer in premixed spark ignition engines part I: Identification of the factors influencing heat transfer

Integral Length Scales and Time Scales of Turbulence in an Optical Spark-Ignition Engine

Modulation of integral length scales of turbulence in an optical SI engine by direct injection of gasoline, iso -octane, ethanol and butanol fuels

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