Modeling Fuel Spray Vapor Distribution With Large Eddy Simulation of Multiple Realizations

2014 ◽  
Author(s):  
P. K. Senecal ◽  
S. Mitra ◽  
E. Pomraning ◽  
Q. Xue ◽  
S. Som ◽  
...  
Keyword(s):  
Adaptive Mesh Refinement ◽  
Current Model ◽  
Mixture Fraction ◽  
Adaptive Mesh ◽  
Dynamic Structure ◽  
Ensemble Averaging ◽  
Eddy Simulation ◽  
Modeling Methodology ◽  
Large Eddy ◽  
Les Model

A state-of-the-art spray modeling methodology, recently presented by Senecal et al. [1, 2, 3], is applied to Large Eddy Simulations (LES) of vaporizing sprays. Simulations of non-combusting Spray H (n-heptane fuel) from the Engine Combustion Network are performed. Adaptive Mesh Refinement (AMR) cell sizes of 0.03125 mm to 0.25 mm are utilized to further demonstrate grid convergence of the Dynamic Structure LES model for diesel sprays. Twenty-eight different realizations are simulated by changing the random number seed used in the spray submodels. Multi-realization (ensemble) averaging, which has been shown to be necessary when comparing to local spray measurements, is performed. Global quantities such as liquid and vapor penetration are compared, as well as local mean mixture fraction and mixture fraction standard deviation. The results suggest that the current model does a reasonable job predicting the major features of the n-heptane spray when appropriate grid resolution is utilized.

Large Eddy Simulation of Vaporizing Sprays Considering Multi-Injection Averaging and Grid-Convergent Mesh Resolution

2013 ◽  
Author(s):  
P. K. Senecal ◽  
E. Pomraning ◽  
Q. Xue ◽  
S. Som ◽  
S. Banerjee ◽  
...  
Keyword(s):  
Adaptive Mesh Refinement ◽  
Mixture Fraction ◽  
Adaptive Mesh ◽  
Dynamic Structure ◽  
Ensemble Averaging ◽  
Eddy Simulation ◽  
Modeling Methodology ◽  
Large Eddy ◽  
Minimum Number ◽  
Les Model

A state-of-the-art spray modeling methodology, recently presented by Senecal et al. [1, 2], is applied to Large Eddy Simulations (LES) of vaporizing sprays. Simulations of non-combusting Spray A (n-dodecane fuel) from the Engine Combustion Network are performed. An Adaptive Mesh Refinement (AMR) cell size of 0.0625 mm is utilized based on the accuracy/runtime tradeoff demonstrated by Senecal et al. [2]. In that work it was shown that grid convergence of key parameters for non-evaporating and evaporating sprays was achieved for cell sizes between 0.0625 and 0.125 mm using the Dynamic Structure LES model. The current work presents an extended and more thorough investigation of Spray A using multi-dimensional spray modeling and the Dynamic Structure LES model. Twenty different realizations are simulated by changing the random number seed used in the spray sub-models. Multi-realization (ensemble) averaging is shown to be necessary when comparing to local spray measurements of quantities such as mixture fraction and gas-phase velocity. Through a detailed analysis, recommendations are made regarding the minimum number of LES realizations required for accurate prediction of Diesel sprays. Finally, the effect of a spray primary breakup model constant on the results is assessed.

Large Eddy Simulation of Vaporizing Sprays Considering Multi-Injection Averaging and Grid-Convergent Mesh Resolution

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
P. K. Senecal ◽  
E. Pomraning ◽  
Q. Xue ◽  
S. Som ◽  
S. Banerjee ◽  
...  
Keyword(s):  
Internal Combustion Engine ◽  
Turbulence Model ◽  
Adaptive Mesh Refinement ◽  
Combustion Engine ◽  
Mixture Fraction ◽  
Dynamic Structure ◽  
Internal Combustion ◽  
Grid Convergence ◽  
Large Eddy ◽  
Les Model

A state-of-the-art spray modeling methodology, recently presented by Senecal et al. (2012, “Grid Convergent Spray Models for Internal Combustion Engine CFD Simulations,” Proceedings of the ASME 2012 Internal Combustion Engine Division Fall Technical Conference, Vancouver, Canada, Paper No. ICEF2012-92043; 2013 “An Investigation of Grid Convergence for Spray Simulations using an LES Turbulence Model,” Paper No. SAE 2013-01-1083) is applied to large eddy simulations (LES) of vaporizing sprays. Simulations of noncombusting Spray A (n-dodecane fuel) from the engine combustion network are performed. An adaptive mesh refinement (AMR) cell size of 0.0625 mm is utilized based on the accuracy/runtime tradeoff demonstrated by Senecal et al. (2013, “An Investigation of Grid Convergence for Spray Simulations using an LES Turbulence Model,” Paper No. SAE 2013-01-1083). In that work, it was shown that grid convergence of key parameters for nonevaporating and evaporating sprays was achieved for cell sizes between 0.0625 and 0.125 mm using the dynamic structure LES model. The current work presents an extended and more thorough investigation of Spray A using multidimensional spray modeling and the dynamic structure LES model. Twenty different realizations are simulated by changing the random number seed used in the spray submodels. Multirealization (ensemble) averaging is shown to be necessary when comparing to local spray measurements of quantities such as mixture fraction and gas-phase velocity. Through a detailed analysis, recommendations are made regarding the minimum number of LES realizations required for accurate prediction of diesel sprays. Finally, the effect of a spray primary breakup model constant on the results is assessed.

LES of Vaporizing Gasoline Sprays Considering Multi-Injection Averaging and Grid-Convergent Mesh Resolution

2015 ◽  
Author(s):  
S. Som ◽  
Z. Wang ◽  
Y. Pei ◽  
P. K. Senecal ◽  
E. Pomraning
Keyword(s):  
Adaptive Mesh Refinement ◽  
Direct Injection ◽  
Injection Pressure ◽  
Adaptive Mesh ◽  
Dynamic Structure ◽  
Gasoline Direct Injection ◽  
Modeling Methodology ◽  
Mesh Resolution ◽  
Minimum Number ◽  
Les Model

A state-of-the-art spray modeling methodology, recently presented by Senecal et al. [1,2,3], is applied to Large Eddy Simulations (LES) of vaporizing gasoline sprays. Simulations of non-combusting Spray G (gasoline fuel) from the Engine Combustion Network are performed. Adaptive mesh refinement (AMR) with cell sizes from 0.09 mm to 0.5 mm are utilized to demonstrate grid convergence of the dynamic structure LES model for the gasoline sprays. Grid settings are recommended to optimize the accuracy/runtime tradeoff for LES-based spray simulations at different injection pressure conditions typically encountered in gasoline direct injection (GDI) applications. Twenty different realizations are simulated by changing the random number seed used in the spray sub-models. It is shown that for global quantities such as spray penetration, comparing a single LES simulation to experimental data is reasonable. Through a detailed analysis using the relevance index (RI) criteria, recommendations are made regarding the minimum number of LES realizations required for accurate prediction of the gasoline sprays.

Accuracy Verification of the Turbulent Flame LES Model by a Methane/Air Burner Flame

2015 ◽  
Author(s):  
Murase Kagenobu ◽  
Oshima Nobuyuki ◽  
Takahashi Yusuke
Keyword(s):  
Laminar Flame ◽  
Mixture Fraction ◽  
Turbulent Flame ◽  
Counter Flow ◽  
Flamelet Model ◽  
Eddy Simulation ◽  
Partially Premixed Combustion ◽  
Large Eddy ◽  
Burner Flame ◽  
Les Model

This paper focuses on the numerical simulation of Sandia National Laboratories “the piloted methane/air burner flame D.” Large Eddy Simulation and 2-scalar flamelet approach are applied for the turbulent and partially premixed combustion field, which is expressed by the LES filtered equations of scalar G for tracking the flame surfaces and mixture fraction of a fuel and an oxidizer. The flamelet data consists of temperature, specific volume and laminar flame speed are calculated by the detail chemical reaction with GRI-Mech 3.0. Two kinds of flamelet data are validated; one is “equilibrium flamelet data” calculated by 0-dimensional equilibrium solution based on equilibrium model; the other is “diffusion flamelet data” calculated by 1-dimensional counter flow solution based on laminar flamelet model. Consequently, the “diffusion flamelet data” gives better result in this type of combustion field.

scholarly journals Improving Large-Eddy Simulation of Neutral Boundary Layer Flow across Grid Interfaces

2015 ◽  
Vol 143 (8) ◽  
pp. 3310-3326 ◽  
Author(s):  
Elijah Goodfriend ◽  
Fotini Katopodes Chow ◽  
Marcos Vanella ◽  
Elias Balaras
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Atmospheric Boundary Layer ◽  
Adaptive Mesh Refinement ◽  
Mixed Model ◽  
Adaptive Mesh ◽  
Grid Refinement ◽  
Eddy Simulation ◽  
Advection Term ◽  
Large Eddy

Abstract Increasing computational power has enabled grid resolutions that support large-eddy simulation (LES) of the atmospheric boundary layer. These simulations often use grid nesting or adaptive mesh refinement to refine the grid in regions of interest. LES generates errors at grid refinement interfaces, such as resolved energy accumulation, that may compromise solution accuracy. In this paper, the authors test the ability of two LES formulations and turbulence closures to mitigate errors associated with the use of LES on nonuniform grids for a half-channel approximation to a neutral atmospheric boundary layer simulation. Idealized simulations are used to examine flow across coarse–fine and fine–coarse interfaces, as would occur in a two-way nested configuration or with block structured adaptive mesh refinement. Specifically, explicit filtering of the advection term and the mixed model are compared to a standard LES formulation with an eddy viscosity model. Errors due to grid interfaces are evaluated by comparison to uniform grid solutions. It is found that explicitly filtering the advection term provides significant benefits, in that it allows both mass and momentum to be conserved across grid refinement interfaces. The mixed model reduces unphysical perturbations generated by wave reflection at the interfaces. These results suggest that the choice of LES formulation and turbulence closure can be used to help control grid refinement interface errors in atmospheric boundary layer simulations.

Large Eddy Simulation of Diesel Spray Combustion With a Multi-Component Drop Vaporization Model

2017 ◽  
Author(s):  
Xiaohua Ren ◽  
Lei Zhang ◽  
Zhongli Ji
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Combustion Process ◽  
Dynamic Structure ◽  
Diesel Spray ◽  
Grid Turbulence ◽  
Fuel Droplets ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Les Model

Large-eddy simulation (LES) of diesel spray and combustion was performed to study its improvement in the simulation of engine in-cylinder dynamics compared to the Reynolds-averaged simulation. For the LES, the dynamic structure approach was used to model the sub-grid turbulence and its interaction with the moving droplets in the spray. A multicomponent vaporization model (MCV) based on the continuous thermodynamics approach and a gamma distribution to describe the distribution of the numerous fuel components, was used to simulate the vaporization of diesel fuel droplets. The MCV model was imbedded into the LES framework in the KIVA-4 program. Using this LES model, a non-evaporative spray in a constant-volume chamber was first simulated. More realistic spray structures and improved agreements in the spray penetration with the experimental data were obtained by the LES compared to a Reynolds-averaged simulation of the same spray. A further simulation of an evaporative diesel spray and the subsequent combustion process using both LES and MCV models was also performed. Improved agreements with the experimental data in the spray structures and soot distributions were also observed using both models.

Implementation of a hybrid Lagrangian filtered density function–large eddy simulation methodology in a dynamic adaptive mesh refinement environment

2021 ◽  
Vol 33 (4) ◽  
pp. 045126
Author(s):  
Laura Pereira de Castro ◽  
Abgail Paula Pinheiro ◽  
Vitor Vilela ◽  
Gabriel Marcos Magalhães ◽  
Ricardo Serfaty ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Density Function ◽  
Adaptive Mesh Refinement ◽  
Mesh Refinement ◽  
Adaptive Mesh ◽  
Filtered Density Function ◽  
Simulation Methodology ◽  
Eddy Simulation ◽  
Large Eddy
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