Cyclic Variability of Large-Scale Turbulent Structures in Directed and Undirected IC Engine Flows

Reuss, David L.

doi:10.4271/2000-01-0246

Cited by 122 publications

(67 citation statements)

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“…These data are available upon request. A previous installation of this engine with a quartz ring in the cylinder allowing optical access to only the combustion chamber has been studied [36][37][38]. Although the present installation of this engine has only been run motored, a spark plug was included in the build so that the in-cylinder flow in its vicinity would be more realistic.…”

Section: Experimental Setup and Piv Data Acquisitionmentioning

confidence: 99%

Evaluating Large-Eddy Simulation (LES) and High-Speed Particle Image Velocimetry (PIV) with Phase-Invariant Proper Orthogonal Decomposition (POD)

Abraham

Liu

Haworth

et al. 2013

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

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and available online here Cet article fait partie du dossier thématique ci-dessous publié dans la revue OGST, Vol. 69, n°1, et téléchargeable ici D o s s i e rDOSSIER Edited by/Sous la direction de : C. Angelberger IFP Energies nouvelles International Conference / Les Rencontres Scientifiques d'IFP Energies nouvelles LES4ICE 2012 -Large Eddy Simulation for Internal Combustion Engine FlowsLES4ICE 2012 -La simulation aux grandes échelles pour les écoulements dans les moteurs à combustion interne Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 69 (2014) Une POD invariante en phase a e´te´applique´e aux donne´es combine´es de vitesse PIV et LES pour tous les angles de vilebrequin, afin d'e´tudier l'e´volution de l'e´coulement en fonction de l'angle de vilebrequin. Les conclusions issues des deux diffe´rentes transformations e´nerge´tiques sont contraste´es. Lorsque l'e´nergie de chaque champ de vitesse est normalise´e, les re´sultats de la POD invariante en phase sont centre´s sur les diffe´rences de structure d'e´coulement et leur e´volution. Par ailleurs, lorsque l'e´nergie de chaque champs de vitesse est conserve´e, les re´sultats de la POD invariante en phase prennent aussi en compte les diffe´rences d'e´nergie entre les donne´es PIV et LES.Abstract -Evaluating Large-Eddy Simulation (LES) and High-Speed Particle Image Velocimetry (PIV) with Phase-Invariant Proper Orthogonal Decomposition (POD) -This study is part of a program to understand the stochastic variations in IC engine flows; in particular, it is a comparison of measured (PIV) and computed (LES) velocity from multiple cycles of the same motored engine.Comparison procedures included traditional RANS (Reynolds Averaged Navier-Stokes) decomposition (ensemble-averaged and RMS (Root Mean Square) velocity), phase-dependent, and phaseinvariant POD. Phase-dependent POD was performed on the PIV and LES samples separately and on the combined samples, thus creating separate or a single POD mode sets, respectively. The phaseinvariant POD was performed both on normalized snapshots and on snapshots where the original energy was conserved.Initial comparisons of the mass-specific kinetic energies of the ensemble average and RMS velocities revealed that the PIV and LES data sets differed significantly during most of the intake stroke. This discrepancy was quantified first by comparing the relevance indices calculated between ensemble average velocity fields and, second, using phase-dependent POD, which quantified cycle-to-cycle flow variations of the RANS average and turbulence. Phase-dependent POD was applied separately to the PIV and LES data sets during the intake stroke (76°ATDCE, After Top Dead Center Exhaust), where the intake-valve jet is strong and the PIV and LES data were earlier found to be significantly different. The cyclic variability of the LES ensemble average was estimated to be significantly higher than that of the PIV data set. POD was also applied to the combined sample of LES and PIV snapshots for quantitative comparison creatin...

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Section: Experimental Setup and Piv Data Acquisitionmentioning

confidence: 99%

Evaluating Large-Eddy Simulation (LES) and High-Speed Particle Image Velocimetry (PIV) with Phase-Invariant Proper Orthogonal Decomposition (POD)

Abraham

Liu

Haworth

et al. 2013

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

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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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“…The intent was to create an extremely large flow CCV that would be obviously detectable and an extreme test for simulations. It was used in its original configuration, the TCC-0, for experiments prior to 2000 [14][15][16][17]. The TCC-II (1) configuration had the same engine geometry (refer to Tab.…”

Section: Introductionmentioning

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

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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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Cyclic Variability of Large-Scale Turbulent Structures in Directed and Undirected IC Engine Flows

Cited by 122 publications

References 10 publications

Evaluating Large-Eddy Simulation (LES) and High-Speed Particle Image Velocimetry (PIV) with Phase-Invariant Proper Orthogonal Decomposition (POD)

Evaluating Large-Eddy Simulation (LES) and High-Speed Particle Image Velocimetry (PIV) with Phase-Invariant Proper Orthogonal Decomposition (POD)

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

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

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