High-Speed Particle Image Velocimetry Study of In-Cylinder Flows with Improved Dynamic Range

Abraham, Preeti S.; Reuss, David L.; Sick, Volker

doi:10.4271/2013-01-0542

Cited by 25 publications

(16 citation statements)

References 24 publications

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“…A1 of Appendix A) but a different intake system, exhaust system, and valve seat (two angles) compared to the TCC-0. The experimental results from the TCC-II configuration were useful for establishing the LES-toexperimental data-comparison protocols, to identify desired improvements in the hardware and operating procedures, and to assess the impact of engine and system imperfections on the in-cylinder flow [18][19][20]. Based on the TCC-II studies, new results are reported here from a third configuration, TCC-III, which has refurbished valve hardware and the intake/exhaust systems upgraded for fired testing.…”

Section: Introductionmentioning

confidence: 97%

“…The upper limit is defined by a maximum particle image displacement of 8 pixels (one quarter of the interrogation window) [21] and lower limit of 0.2 pixels (sub-pixel displacement detection) is based on a previous analysis performed under optical engine conditions [22,23]. To make best use of this velocity range, the laser-pulse separation, dt, was adjusted on a per CAD base during the cycle [20]. Here, dt ranged from 3 ls during the intake and exhaust strokes when velocities are high, to 80 ls around TDC compression when velocities are lowest.…”

Section: Piv Measurementsmentioning

confidence: 99%

See 1 more Smart Citation

TCC-III Engine Benchmark for Large-Eddy Simulation of IC Engine Flows

Schiffmann

Gupta

Reuss

et al. 2015

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-A collaborative effort is described to benchmark the TCC-III engine, and to illustrate the application of this data for the evaluation of sub-grid scale models and valve simulation details on the fidelity of Large-Eddy Simulations (LES). The TCC-III is a spark ignition 4-stroke 2-valve engine with a flat head and piston and is equipped with a full quartz liner for maximum optical access that allows high-speed flow measurements with Particle Image Velocimetry (PIV); the TCC-III has new valve seats and a modified intake-system compared to previous configurations. This work is an extension of a previous study at an engine speed of 800 RPM and an intake manifold pressure (MAP) of 95 kPa, where a one-equation eddy viscosity LES model yielded accurate qualitative and quantitative predictions of ensemble averaged mean and RMS velocities during the intake and compression stroke. Here, experimental data were acquired with parametric variation of engine speed and intake manifold absolute pressure to assess the capability of LES models over a range of operating conditions of practical relevance. This paper focuses on the repeatability and accuracy of the measured PIV data, acquired at 1 300 RPM, at two different MAP (95 kPa and 40 kPa), and imaged at multiple data planes and crank angles. Two examples are provided, illustrating the application of this data to LES model development. In one example, the experimental data are used to distinguish between the efficacies of a one-equation eddy viscosity model versus a dynamic structure one-equation model for the sub-grid stresses. The second example addresses the effects of numerical intake-valve opening strategy and local mesh refinement in the valve curtain.Résumé -Benchmark de moteur de référence TCC-III pour la simulation aux grandes échelles (Large-Eddy Simulations, LES) de l'écoulement dans les moteurs à combustion interne -Un projet collaboratif est décrit, visant à caractériser le moteur TCC-III et à illustrer l'application de ces données pour l'évaluation de modèles de sous-maille et des détails de simulation des soupapes sur la fidélité de simulations aux grandes échelles. Le TCC-III est un moteur à allumage commandé 4 temps à deux

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Section: Introductionmentioning

confidence: 97%

Section: Piv Measurementsmentioning

confidence: 99%

TCC-III Engine Benchmark for Large-Eddy Simulation of IC Engine Flows

Schiffmann

Gupta

Reuss

et al. 2015

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

show abstract

“…Issues of into-plane motion of particles during PIV image capture may also require closer analysis to quantify their exact contribution effects since the dynamic resolution of the system is fixed over a single plane and over different crank angles. This may mask features in the characterisation of flow fields with such steep gradients of directed flows on and into planes and has attracted attention in a recent publication where the in-cylinder flow was studied by PIV image frame time separations that were dynamically varied as a function of crank angle [62]. In the current study, the absolute values of v-velocity obtained by LDV were typically 10-20% higher than those of PIV in the intake stroke, with even greater differences observed during compression at velocity levels of 1-2 m/s or lower.…”

Section: Ensemble Averaged Piv and Ldv Flow Field At X=10 MMmentioning

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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“…Here, the PIV uncertainty was evaluated using the velocity-error analysis approach presented in Ref. [16,33]. The PIV experimental settings, summarized in Table 2, were designed to achieve a maximum in-plane particle displacement of eight pixels to avoid biasing the velocity towards low values.…”

Section: The Single-cylinder Enginementioning

confidence: 99%

The role of spray-enhanced swirl flow for combustion stabilization in a stratified-charge DISI engine

Zeng¹,

Sjöberg²,

Reuss³

et al. 2016

Combustion and Flame

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Implementation of spray-guided stratified-charge direct-injection spark-ignited (DISI) engines is inhibited by the occurrence of misfire and partial burns. Engine-performance tests demonstrate that increasing engine speed induces combustion instability, but this deterioration can be prevented by generating swirling flow during the intake stroke. In-cylinder pressure-based heat-release analysis reveals that the appearance of poor-burn cycles is not solely dependent on the variability of early flame-kernel growth. Cycles can experience burning-rate regression during later combustion stages and may or may not recover before the end of the cycle. Thermodynamic analysis and optical diagnostics are used here to clarify why swirl improves the combustion repeatability from cycle to cycle.The fluid dynamics of swirl/spray interaction was previously demonstrated using high-speed PIV measurements of in-cylinder motored flow. It was found that the sprays of the multi-hole injector redistribute the intake-generated swirl flow momentum, thereby creating a better-centered higher angularmomentum vortex with reduced variability. The engine operation with high swirl was found to have significant improvement in cycle-to-cycle variations of both flow pattern and flow momentum. This paper is an extension of the previous work. Here, PIV measurements and flame imaging are applied to fired operation for studying how the swirl flow affects variability of ignition and subsequent combustion phases. PIV results for fired operation are consistent with the measurements made of motored flow. They demonstrate that the spark-plasma motion is highly correlated with the direction of the gas flow in the vicinity of the spark-plug gap. Without swirl, the plasma is randomly stretched towards either side of the spark plug, causing variability in the ignition of the two spray plumes that are straddling the spark plug. In contrast, swirl flow always convects the spark plasma towards one spray plume, causing a more repeatable ignition. The swirl decreases local RMS velocity, consistent with an observed reduction of early-burn variability. Broadband flame imaging demonstrates that with swirl, the flame consistently propagates in multiple directions to consume fuel-air mixtures within the piston bowl. In contrast, operation without swirl displays higher variability of flame-spread patterns, occasionally causing the appearance of partial-burn cycles.

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High-Speed Particle Image Velocimetry Study of In-Cylinder Flows with Improved Dynamic Range

Cited by 25 publications

References 24 publications

TCC-III Engine Benchmark for Large-Eddy Simulation of IC Engine Flows

TCC-III Engine Benchmark for Large-Eddy Simulation of IC Engine Flows

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

The role of spray-enhanced swirl flow for combustion stabilization in a stratified-charge DISI engine

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