Evaluation and validation of large-eddy simulation sub-grid spray dispersion models using high-fidelity volume-of-fluid simulation data and engine combustion network experimental data

Tsang, Chi-Wei; Kuo, Chia-Wei; Trujillo, Mario F.; Rutland, Christopher J.

doi:10.1177/1468087418772219

Cited by 18 publications

(17 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, Wehrfritz et al [34] and Xue et al [35] investigated different secondary breakup models, including the Kelvin-Helmholtz Rayleigh-Taylor (KHRT) and the enhanced Taylor analogy breakup (ETAB) models, and different SGS models, including Smagorinsky, K sgs -model, and ILES, respectively, for various grid resolutions. Tsang et al [36] developed and validated a model that predicts the spray sub-grid dispersion velocity. Senecal et al [37] additionally studied LES multi-realization uncertainties on global and local spray characteristics.…”

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of ECN Spray A: Sensitivity Study on Modeling Assumptions

et al. 2020

View full text Add to dashboard Cite

In this study, various mixing and evaporation modeling assumptions typically considered for large-eddy simulation (LES) of the well-established Engine Combustion Network (ECN) Spray A are explored. A coupling between LES and Lagrangian particle tracking (LPT) is employed to simulate liquid n-dodecane spray injection into hot inert gaseous environment, wherein Lagrangian droplets are introduced from a small cylindrical injection volume while larger length scales within the nozzle diameter are resolved. This LES/LPT approach involves various modeling assumptions concerning the unresolved near-nozzle region, droplet breakup, and LES subgrid scales (SGS) in which their impact on common spray metrics is usually left unexplored despite frequent utilization. Here, multi-parametric analysis is performed on the effects of (i) cylindrical injection volume dimensions, (ii) secondary breakup model, particularly Kelvin–Helmholtz Rayleigh–Taylor (KHRT) against a no-breakup model approach, and (iii) LES SGS models, particularly Smagorinsky and one-equation models against implicit LES. The analysis indicates the following findings: (i) global spray characteristics are sensitive to radial dimension of the cylindrical injection volume, (ii) the no-breakup model approach performs equally well, in terms of spray penetration and mixture formation, compared with KHRT, and (iii) the no-breakup model is generally insensitive to the chosen SGS model for the utilized grid resolution.

show abstract

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of ECN Spray A: Sensitivity Study on Modeling Assumptions

et al. 2020

View full text Add to dashboard Cite

show abstract

“…It is worthwhile to note that the experimental studies on the droplet acceleration statistics [29,30] have shown that the variance of acceleration scales with d 1 3 , as it is the case in equation (18).…”

Section: Standard Sgs Model For Dispersionmentioning

confidence: 88%

“…At the same time, the liquid is not yet well atomized, with liquid elements typically larger than the local Kolmogorov length scale. Equation (18) assumes the drag to be independent of the laminar viscosity. It is coherent with the classical observation for the sphere drag if Re > 1000.…”

Section: Les-strip Model For Diesel Spraysmentioning

confidence: 99%

“…The later is calculated from the subgrid kinetic energy (k sgs ) and assumed to be piece-wise continuous in time [17]. Tsang et al [18] further extended the model by decomposing the SGS velocity into deterministic and stochastic components, where the former is evaluated from deconvolution [15] and the later from the dispersion model [17]. The performance of the SGS model under diesel spray conditions has been evaluated.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessment of LES-STRIP approach for modeling of droplet dispersion in diesel-like sprays

Oruganti¹,

Millet²,

Gorokhovski³

2019

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

View full text Add to dashboard Cite

In this paper, the stochastic equations of droplet motion in turbulent flow, proposed recently by Gorokhovski and Zamansky (2018, Phys. Rev. Fluids, 3, 3, 034602), are assessed for turbulent spray dispersion in diesel like conditions along with Large Eddy Simulation (LES) for the gaseous flow. For droplets above the Kolmogorov length scale, this model introduces the concept of the stochastic drag, independently of laminar viscosity. For droplets below the Kolmogorov length scale, the model equation does depend on the laminar viscosity through the Stokes drag but the particle motion is stochastically forced. Both the stochastic drag and the stochastic forcing of the Stokes drag equation are based on the simple log-normal stochastic process for the viscous dissipation () "seen" along the droplet trajectory. In this paper, this model is applied in the framework of two-way coupling, wherein the turbulence generated by the spray inturn controls the spray dispersion. The criterion for the choice of one of the approaches, i.e., the stochastic drag or the stochastic forcing, follows the classical condition for drag coefficient based on the droplet Reynolds number (Re p ). The non-vaporizing spray experiments from Engine Combustion Network (ECN) are used as test cases. In addition to the comparison of the spray penetration length, spreading angle and spray structure with the experimental data, a qualitative analysis of the statistics of the droplet acceleration and gas phase velocities is presented. It was shown that the new approach is much more effective in modeling the spray dynamics on relatively coarser mesh. Consequently, the new approach in the framework of two-way coupling may predict the preferential concentration effects better, which is important for spray combustion.

show abstract

“…In the past two decades, LES has been extensively developed for engine modeling [6], making significant progress towards industry-grade maturity. Nonetheless, LES/LP coupling is still relatively new [7][8][9][10][11], thus leaving room for further research and development in that area. One of the main issues in LES/LP matching is the spatial grid resolution which for LES has to be sufficiently fine to resolve at least the main energy-containing flow structures.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Scale-Resolving Methodology for the Multidimensional Simulation of GDI Sprays

2019

View full text Add to dashboard Cite

The introduction of new emissions tests in real driving conditions (Real Driving Emissions—RDE) as well as of improved harmonized laboratory tests (World Harmonised Light Vehicle Test Procedure—WLTP) is going to dramatically cut down NOx and particulate matter emissions for new car models that are intended to be fully Euro 6d compliant from 2020 onwards. Due to the technical challenges related to exhaust gases’ aftertreatment in small-size diesel engines, the current powertrain development trend for light passenger cars is shifted towards the application of different degrees of electrification to highly optimized gasoline direct injection (GDI) engines. As such, the importance of reliable multidimensional computational tools for GDI engine optimization is rapidly increasing. In the present paper, we assess a hybrid scale-resolving turbulence modeling technique for GDI fuel spray simulation, based on the Engine Combustion Network “Spray G” standard test case. Aspects such as the comparison with Reynolds-averaged methods and the sensitivity to the spray model parameters are discussed, and strengths and uncertainties of the analyzed hybrid approach are pointed out. The outcomes of this study serve as a basis for the evaluation of scale-resolving turbulence modeling options for the development of next-generation directly injected thermal engines.

show abstract

Evaluation and validation of large-eddy simulation sub-grid spray dispersion models using high-fidelity volume-of-fluid simulation data and engine combustion network experimental data

Cited by 18 publications

References 49 publications

Large-Eddy Simulation of ECN Spray A: Sensitivity Study on Modeling Assumptions

Large-Eddy Simulation of ECN Spray A: Sensitivity Study on Modeling Assumptions

Assessment of LES-STRIP approach for modeling of droplet dispersion in diesel-like sprays

Evaluation of a Scale-Resolving Methodology for the Multidimensional Simulation of GDI Sprays

Contact Info

Product

Resources

About