Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part I: 3D Analyses

Bozza, Fabio; Bellis, Vincenzo De; Berni, Fabio; D'Adamo, Alessandro; Maresca, Luca

doi:10.4271/2018-01-0850

Cited by 23 publications

(41 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Two-valve arrangement. = √ 2 + 2 (23) Dashed red profiles in Figure 28a hence refer to the above definition. 3D tumble trends are surprisingly well reproduced by the 0D model.…”

Section: Two-valve Enginementioning

confidence: 99%

“…Based on the authors' knowledge, in the current literature, a model able to simultaneously and properly reproduce both engine operating parameters, including intake valve strategy (both EIVC, conventional Full Lift -FL, and LIVC) and engine geometrical parameters, is still missing. The main aim of this work is its achieving, where 3D results presented in companion part I paper [23] are employed to refine and validate a model previously developed by the authors [24]. The model represents an extension of a conventional two-equation K-k formulation, where tumble and dissipation rate equations are also added (4-eq.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part II: Model Concept, Validation and Discussion

Bozza¹,

Teodosio²,

Bellis³

et al. 2018

SAE Technical Paper Series

Self Cite

View full text Add to dashboard Cite

As known, reliable information about underlying turbulence intensity is a mandatory prerequisite to predict the burning rate in quasidimensional combustion models. Based on 3D results reported in the companion part I paper, a quasi-dimensional turbulence model, embedded under the form of "user routine" in the GT-Power™ software, is here presented in detail. A deep discussion on the model concept is reported, compared to the alternative approaches available in the current literature. The model has the potential to estimate the impact of some geometrical parameters, such as the intake runner orientation, the compression ratio, or the bore-to-stroke ratio, thus opening the possibility to relate the burning rate to the engine architecture. Preliminarily, a well-assessed approach, embedded in GT-Power commercial software v.2016, is utilized to reproduce turbulence characteristics of a VVA engine. This test showed that the model fails to predict tumble intensity for particular valve strategies, such LIVC, thus justifying the need for additional refinements. The model proposed in this work is conceived to solve 3 balance equations, for mean flow kinetic energy, tumble vortex momentum, and turbulent kinetic energy (3-eq. concept). An extended formulation is also proposed, which includes a fourth equation for the dissipation rate, allowing to forecast the integral length scale (4-eq. concept). The impact of the model constants is parametrically analyzed in a first step, and a tuning procedure is advised. Then, a comparison between the 3-and the 4-eq. concepts is performed, highlighting the advantages of the 3-eq. version, in terms of prediction accuracy of turbulence speed-up at the end of the compression stroke. An extensive 3-eq. model validation is then realized according to different valve strategies and engine speeds. The user-model is then utilized to foresee the effects of main geometrical parameters analyzed in part I, namely the intake runner orientation, the compression ratio, and the bore-to-stroke ratio. A two-valve per cylinder engine is also considered. Temporal evolutions of 0D-and 3D-derived mean flow velocity, turbulent intensity, and tumble velocity present very good agreements for each investigated engine geometry and operating condition. The model, particularly, exhibits the capability to accurately predict the tumble trends by varying some geometrical parameter of the engine, which is helpful to estimate the related impact on the burning rate. Summarizing, the developed 0D model well estimates the in-cylinder turbulence characteristics, without requiring any tuning constants adjustment with engine speed and valve strategy. In addition, it demonstrates the capability to properly take into account the intake duct orientation and the compression ratio without tuning adjustments. Some minor tuning variation allows predicting the effects of bore-to-stroke ratio, as well. Finally, the model is verified to furnish good agreements also for a two-valve per cylinder engine, and with reference to two different h...

show abstract

“…Two-valve arrangement. = √ 2 + 2 (23) Dashed red profiles in Figure 28a hence refer to the above definition. 3D tumble trends are surprisingly well reproduced by the 0D model.…”

Section: Two-valve Enginementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part II: Model Concept, Validation and Discussion

Bozza¹,

Teodosio²,

Bellis³

et al. 2018

SAE Technical Paper Series

Self Cite

View full text Add to dashboard Cite

show abstract

“…In order to develop and validate the proposed model, various 3D simulations are carried out with the commercial software STAR-CD v4.28, as described in detail in [23]. The computational domain includes in-head intake and exhaust ports.…”

Section: Description Of Tested Operating Conditions and Engine Configmentioning

confidence: 99%

“…The reliability of this model is tested with reference to the 3D results obtained for Engine A, for different valve strategies and engine speeds. According to the averaging technique discussed in [23], the target 3D data refer to the mass-averages of mean flow velocity, turbulent kinetic energy, and integral length scale. The turbulence intensity and the dissipation rate are derived from the combination of the above quantities.…”

Section: Comparison With Gt-power Turbulence Modelmentioning

confidence: 99%

“…The main aim of this work is the achievement of the above model features. For this reason, the 3D results presented in [23] are employed to refine and validate a model previously developed by the authors [24]. The advanced model represents an extension of a conventional two-equation K-k formulation, where the tumble and dissipation rate equations are added (4-eq.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Refined 0D Turbulence Model to Predict Tumble and Turbulence in SI Engines

Bozza¹,

Teodosio

Bellis

et al. 2018

SAE Int. J. Engines

Self Cite

View full text Add to dashboard Cite

In this work, the refinement of a phenomenological turbulence model developed in recent years by the authors is presented in detail. As known, reliable information about the underlying turbulence intensity are a mandatory prerequisite to predict the burning rate in phenomenological combustion models. The model is embedded under the form of "user routine" in the GT-Power™ software. The main advance of the proposed approach is the potential to describe the effects on the in-cylinder turbulence of some geometrical parameters, such as the intake runner orientation, the compression ratio, the bore-to-stroke ratio and the valve number. The model is based on 3 balance equations, referring to the mean flow kinetic energy, the tumble vortex momentum, and the turbulent kinetic energy (3-eq. concept). An extended formulation is also proposed, which includes a fourth equation for the dissipation rate, allowing to forecast also the integral length scale (4-eq. concept). The model consistency is verified against 3D results under motored operations for various operating conditions and engine geometrical architectures. The temporal evolutions of the 0D-derived mean flow velocity, turbulent intensity, and tumble velocity present very good agreement with the 3D outcomes. The model exhibits the capability to accurately predict the tumble trends by varying some engine geometrical parameters. The proposed 0D model proves to correctly estimate the in-cylinder turbulence characteristics, without requiring any tuning adjustment with the engine speed and the valve strategy. In addition, it demonstrates the capability to properly take into account the intake duct orientation and the compression ratio without any case-dependent tuning. Some minor tunings are required to predict the effects of the bore-to-stroke ratio. The model also shows an adequate accuracy for a two-valve per cylinder engine, and for two different high-performance engines.

show abstract

Zero-dimensional turbulence modeling of a spark ignition engine in a Miller cycle « Dethrottling » approach using a variable valve timing system

Perceau

Guibert

Guilain

2021

Applied Thermal Engineering

View full text Add to dashboard Cite

Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part I: 3D Analyses

Cited by 23 publications

References 21 publications

Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part II: Model Concept, Validation and Discussion

Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part II: Model Concept, Validation and Discussion

A Refined 0D Turbulence Model to Predict Tumble and Turbulence in SI Engines

Zero-dimensional turbulence modeling of a spark ignition engine in a Miller cycle « Dethrottling » approach using a variable valve timing system

Contact Info

Product

Resources

About