3D proper orthogonal decomposition analysis of engine in-cylinder velocity fields

Cao, Jingjing; Ma, Zhewen; Li, Xuesong

doi:10.1088/1361-6501/ab25c1

Cited by 6 publications

(3 citation statements)

References 35 publications

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“…Other decomposition methodologies exist in the literature. For example, the Proper Orthogonal Decomposition (POD) is a statistical method that has been widely applied to in-cylinder velocity data, obtained from LES and mainly from PIV measurements by a number of groups [38][39][40][41][42]. It allows the velocity field to be decomposed into a set of orthogonal basis functions.…”

Section: Flow Analysis Tools 41 2d Multivariate Empirical Mode Decomp...mentioning

confidence: 99%

ECFM-LES modeling with AMR for the CCV prediction and analysis in lean-burn engines

Maio

Ding

Truffin

et al. 2022

Sci. Tech. Energ. Transition

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A Large-Eddy Simulation (LES) modeling framework, dedicated to ultra-lean spark-ignition engines, is proposed and validated in the present work. A direct injection research engine is retained as benchmark configuration. The LES model is initially validated using the cold gas-exchange conditions by comparing numerical results with PIV (Particle Imaging Velocimetry) experimental data. Then, the fired configuration is investigated, combining ECFM (Extended Coherent Flame Model) turbulent combustion model with Adaptive Mesh Refinement (AMR). The capability of the model to reproduce experimental pressure envelope and cycle-to-cycle variability is assessed. Within the major scope of the work, a particular focus on the Combustion Cyclic Variability (CCV) is made correlating them with the variability encountered in the in-cylinder aerodynamic variations. R3P4. Finally two post-processing tools, Empirical Mode Decomposition (EMD) and Γ3p function, are proposed and combined to analyse for the first time the aerodynamic tumble-based in-cylinder velocity field. Both tools make it possible to get deeply into the insight and visualization of the flow field and to understand the links between its cyclic variability and the combustion cyclic variability.

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Section: Flow Analysis Tools 41 2d Multivariate Empirical Mode Decomp...mentioning

confidence: 99%

ECFM-LES modeling with AMR for the CCV prediction and analysis in lean-burn engines

Maio

Ding

Truffin

et al. 2022

Sci. Tech. Energ. Transition

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show abstract

“…Traditional non-intrusive measurement techniques such as laser Doppler anemometry (LDA), particle image velocimetry (PIV), and magnetic resonance velocimetry (MRV) have been widely used for studying in-cylinder flow in combustion engines [27,[44][45][46][47][48][49][50][51]. Highspeed PIV is a suitable method for measuring time-resolved in-cylinder flow fields and capturing CCV as well as large-scale fluctuations [52,53].…”

Section: Introduction 1motivationmentioning

confidence: 99%

Investigation of Flow Fields Emanating from Two Parallel Inlet Valves Using LES, PIV, and POD

Hoffmann,

Vera-Tudela,

Mirsch

et al. 2023

Energies

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Understanding cycle-to-cycle variations (CCV) is of practical importance for the combustion of fossil and renewable fuels, as increasingly stringent emission regulations require reductions in the negative effects of such variations. The subject of this study is the flow around inlet valves, since oscillations of such inlet flows affect the flow structure in the cylinder and are thus one of the causes of CCV. To this end, a parametric analysis of the influences of the mass flow rate and valve lift of two parallel engine intake valves on the flow structures is performed. This follows on from an earlier similar study where the flow around a single intake valve was investigated. To analyse the flow behaviour and, in particular, the interactions of the flow leaving these two valves, an optical test rig for 2D particle image velocimetry (PIV) and a large eddy simulation (LES) are used. Proper orthogonal decomposition (POD), together with a quadruple decomposition and the Reynolds stress transport equations, are used to study the turbulence phenomena. The PIV and LES results are in good agreement with each other. The detailed LES analysis of the flow structures shows that, for small valve lifts, the flow separates along the whole perimeter of the intake valve, and for larger valve lifts, the flow escapes only to one side. This is, for combustion engines with the tumble concept, the stage at which the tumble movement develops. Moreover, the flow structures are strongly influenced by the valve lift, while they are unaffected by the variation in the mass flow. The turbulent kinetic energy in the flow field increases quadratically with a decreasing valve lift and increasing mass flow. The large, high-energetic flow structures are particularly dominant near the jet, and the small, low-energetic structures are homogeneously distributed within the flow field. The specific Reynolds stress transport equation shows the limitations of two-dimensionality and large timesteps in the PIV results and the limitations of the LES model.

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“…It is an adaptive method in which the basis functions are computed from the data itself. POD has been commonly applied to in-cylinder flow in order to extract the dominant structures and study their CCV [5,9,13,27]. However in POD filtering, the separation between mean flow and turbulent fluctuations is performed by truncating the series of the modes and this requires an ad hoc criterion [7,40].…”

Section: Introductionmentioning

confidence: 99%

Development and Application of Bivariate 2D-EMD for the Analysis of Instantaneous Flow Structures and Cycle-to-Cycle Variations of In-cylinder Flow

Sadeghi

Truffin

Peterson

et al. 2020

Flow Turbulence Combust

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3D proper orthogonal decomposition analysis of engine in-cylinder velocity fields

Cited by 6 publications

References 35 publications

ECFM-LES modeling with AMR for the CCV prediction and analysis in lean-burn engines

ECFM-LES modeling with AMR for the CCV prediction and analysis in lean-burn engines

Investigation of Flow Fields Emanating from Two Parallel Inlet Valves Using LES, PIV, and POD

Development and Application of Bivariate 2D-EMD for the Analysis of Instantaneous Flow Structures and Cycle-to-Cycle Variations of In-cylinder Flow

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