Evaluation of the flame propagation within an SI engine using flame imaging and LES

He, Chao; Kuenne, G.; Yildar, Esra; Oijen, J.A. van; Mare, Francesca di; Sadiki, A.; Ding, Carl-Philipp; Baum, Elias; Peterson, Brian; Böhm, Benjamin; Janicka, J.

doi:10.1080/13647830.2017.1343498

Cited by 9 publications

(4 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is anticipated that flow velocity is not only faster near the wall, but also at other chamber locations, which can be a driving force for faster flame propagation. This phenomena can be seen in previous flame/flow studies within this engine [24][25][26]. At the same time, flame propagation in the FOV also accelerates unburnt gas downstream the flame, generating higher velocities.…”

Section: Conditional Averaging Analysissupporting

confidence: 75%

Flame/flow dynamics at the piston surface of an IC engine measured by high-speed PLIF and PTV

Ding

Peterson

Schmidt

et al. 2019

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

Resolving fluid transport at engine surfaces is required to predict transient heat loss, which is becoming increasingly important for the development of high-efficiency internal combustion engines (ICE). The limited number of available investigations have focused on non-reacting flows near engine surfaces, while this work focuses on the near-wall flow field dynamics in response to a propagating flame front. Flow-field and flame distributions were measured simultaneously at kHz repetition rates using particle tracking velocimetry (PTV) and planar laser induced fluorescence (PLIF) of sulfur dioxide (SO2). Measurements were performed near the piston surface of an optically accessible engine operating at 800 rpm with homogeneous, stoichiometric isooctane-air mixtures. High-speed measurements reveal a strong interdependency between near-wall flow and flame development which also influences subsequent combustion. A conditional analysis is performed to analyze flame/flow dynamics at the piston surface for cycles with 'weak' and 'strong' flow velocities parallel to the surface. Faster flame propagation associated with higher velocities before ignition demonstrates a stronger flow acceleration ahead of the flame. Flow acceleration associated with an advancing flame front is a transient feature that strongly influences boundary layer development. The distance from the wall to 75% maximum velocity (δ75) is analyzed to compare boundary layer development between fired and motored datasets. Decreases in δ75 are strongly related to flow acceleration produced by an approaching flame front. Measurements reveal strong deviations of the boundary layer flow between fired and motored datasets, emphasizing the need to consider transient flow behavior when modelling boundary layer physics for reacting flows.

show abstract

Section: Conditional Averaging Analysissupporting

confidence: 75%

Flame/flow dynamics at the piston surface of an IC engine measured by high-speed PLIF and PTV

Ding

Peterson

Schmidt

et al. 2019

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

show abstract

“…Operating parameters, shown in Table 1, were chosen to mimic a low-load engine operation, but the engine was not operated in the fired mode. Operating conditions were chosen to agree with the comprehensive velocimetry databases for the motored flow (Baum et al 2014;Freudenhammer et al 2015;Zentgraf et al 2016), spray-induced flow (Peterson et al 2015a;Peterson et al 2017) and reacting flow (Peterson et al 2015b;He et al 2017;Peterson et al 2019;Ding et al 2019) associated with this engine. Silicone oil droplets (0.5 μm diameter) were seeded into the intake air for PIV by means of an aerosol generator (AGF 10.0, Palas).…”

Section: Methodsmentioning

confidence: 99%

An application of tomographic PIV to investigate the spray-induced turbulence in a direct-injection engine

Hill

Ding

Baum

et al. 2019

International Journal of Multiphase Flow

View full text Add to dashboard Cite

Fuel sprays produce high-velocity, jet-like flows that impart turbulence onto the ambient flow field. This spray-induced turbulence augments rapid fuel-air mixing, which has a primary role in controlling pollutant formation and cyclic variability in direct-injection engines. This paper presents tomographic particle image velocimetry (TPIV) measurements to analyse the 3D spray-induced turbulence during the intake stroke of a direct-injection spark-ignition (DISI) engine. The spray produces a strong spray-induced jet (SIJ) in the far field, which travels through the cylinder and imparts turbulence onto the surrounding flow. Planar high-speed PIV measurements at 4.8 kHz are combined with TPIV at 3.3 Hz to evaluate spray particle distributions and validate TPIV measurements in the particle laden flow. A comprehensive uncertainty analysis is performed to assess the uncertainty associated with individual vorticity and strain rate components. TPIV analyses quantify the spatial domain of the turbulence in relation to the SIJ and describe how turbulent flow features such as turbulent kinetic energy (TKE), strain rate (S) and vorticity (Ω) evolve into the surrounding flow field. Access to the full S and Ω tensors facilitate the evaluation of turbulence for individual spray events. TPIV images reveal the presence of strong shear layers (visualized by high S magnitudes) and pockets of elevated vorticity along the immediate boundary of the SIJ. S and Ω values are extracted from spatial domains extending in 1mm increments from the SIJ. Turbulence levels are greatest within the 0-1mm region from the SIJ boarder and dissipate with radial distance. Individual strain rate and vorticity components are analyzed in detail to describe the relationship between local strain rates and 3D vortical structures produced within strong shear layers of the SIJ. Analyses are intended to understand the flow features responsible for rapid fuel-air mixing and provide valuable data for the development of numerical models.

show abstract

“…A detailed analysis of these stratifications close to the Spark Timing (ST) is experimentally complex [3]. While RANS approach is limited to the description of the mean cycle and consequently is not able to reproduce cycle-to-cycle variation, Large-Eddy Simulation (LES) can provide a detailed insight of the coupling between injection, turbulence and combustion, thanks to its unique capability to reproduce highly transient and turbulent phenomena [4].…”

Section: Introductionmentioning

confidence: 99%

LES study on mixing and combustion in a Direct Injection Spark Ignition engine

Iafrate

Robert

Michel

et al. 2018

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

View full text Add to dashboard Cite

Downsized spark ignition engines coupled with a direct injection strategy are more and more attractive for car manufacturers in order to reduce pollutant emissions and increase efficiency. However, the combustion process may be affected by local heterogeneities caused by the interaction between the spray and turbulence. The aim for car manufacturers of such engine strategy is to create, for mid-to-high speeds and mid-up-high loads, a mixture which is as homogeneous as possible. However, although injection occurs during the intake phase, which favors homogeneous mixing, local heterogeneities of the equivalence ratio are still observed at the ignition time. The analysis of the mixture preparation is difficult to perform experimentally because of limited optical accesses. In this context, numerical simulation, and in particular Large Eddy Simulation (LES) are complementary tools for the understanding and analysis of unsteady phenomena. The paper presents the LES study of the impact of direct injection on the mixture preparation and combustion in a spark ignition engine. Numerical simulations are validated by comparing LES results with experimental data previously obtained at IFPEN. Two main analyses are performed. The first one focuses on the fuel mixing and the second one concerns the effect of the liquid phase on the combustion process. To highlight these phenomena, simulations with and without liquid injection are performed and compared.

show abstract

Evaluation of the flame propagation within an SI engine using flame imaging and LES

Cited by 9 publications

References 65 publications

Flame/flow dynamics at the piston surface of an IC engine measured by high-speed PLIF and PTV

Flame/flow dynamics at the piston surface of an IC engine measured by high-speed PLIF and PTV

An application of tomographic PIV to investigate the spray-induced turbulence in a direct-injection engine

LES study on mixing and combustion in a Direct Injection Spark Ignition engine

Contact Info

Product

Resources

About