scholarly journals Large Eddy Simulation of Direct Injection Processes for Hydrogen and LTC Engine Applications

2008 ◽  
Author(s):  
Tomasz G. Drozda ◽  
Joseph C. Oefelein
Keyword(s):  
Large Eddy Simulation ◽  
Direct Injection ◽  
Eddy Simulation ◽  
Large Eddy

Large-Eddy Simulation of a Swirl-Stabilized, Lean Direct Injection Spray Combustor

2006 ◽  
Author(s):  
Mehmet Kırtas¸ ◽  
Nayan Patel ◽  
Vaidyanathan Sankaran ◽  
Suresh Menon
Keyword(s):  
Large Eddy Simulation ◽  
Vortex Breakdown ◽  
Direct Injection ◽  
Reacting Flow ◽  
Mean Velocity ◽  
Recirculation Bubble ◽  
Lean Direct Injection ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Recirculation Zones

Large-eddy simulation (LES) of a lean-direct injection (LDI) combustor is reported in this paper. The full combustor and all the six swirl vanes are resolved and both cold and reacting flow simulations are performed. Cold flow predictions with LES indicate the presence of a broad central recirculation zone due to vortex breakdown phenomenon near the dump plane and two corner recirculation zones at the top and bottom corner of the combustor. These predicted features compare well with the experimental non-reacting data. Reacting case simulated a liquid Jet-A fuel spray using a Lagrangian approach. A three-step kinetics model that included CO and NO is used for the chemistry. Comparison of mean velocity field predicted in the reacting LES with experiments shows reasonable agreement. Comparison with the non-reacting case shows that the centerline recirculation bubble is shorter but more intense in the reacting case.

Large-eddy simulation analysis of knock in a direct injection spark ignition engine

2018 ◽  
Vol 20 (7) ◽  
pp. 765-776 ◽  
Author(s):  
Anthony Robert ◽  
Karine Truffin ◽  
Nicolas Iafrate ◽  
Stephane Jay ◽  
Olivier Colin ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Simulation Analysis ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Eddy Simulation ◽  
Oscillation Analysis ◽  
Spark Timing ◽  
Large Eddy ◽  
Direct Injection Spark Ignition

Downsized spark ignition engines running under high loads have become more and more attractive for car manufacturers because of their increased thermal efficiency and lower CO2 emissions. However, the occurrence of abnormal combustions promoted by the thermodynamic conditions encountered in such engines limits their practical operating range, especially in high efficiency and low fuel consumption regions. One of the main abnormal combustion is knock, which corresponds to an auto-ignition of end gases during the flame propagation initiated by the spark plug. Knock generates pressure waves which can have long-term damages on the engine, that is why the aim for car manufacturers is to better understand and predict knock appearance. However, an experimental study of such recurrent but non-cyclic phenomena is very complex, and these difficulties motivate the use of computational fluid dynamics for better understanding them. In the present article, large-eddy simulation (LES) is used as it is able to represent the instantaneous engine behavior and thus to quantitatively capture cyclic variability and knock. The proposed study focuses on the large-eddy simulation analysis of knock for a direct injection spark ignition engine. A spark timing sweep available in the experimental database is simulated, and 15 LES cycles were performed for each spark timing. Wall temperatures, which are a first-order parameter for knock prediction, are obtained using a conjugate heat transfer study. Present work points out that LES is able to describe the in-cylinder pressure envelope whatever the spark timing, even if the sample of LES cycles is limited compared to the 500 cycles recorded in the engine test bench. The influence of direct injection and equivalence ratio stratifications on combustion is also (MAPO) analyzed. Finally, focusing on knock, a Maximum Amplitude Pressure Oscillation analysis (MAPO) is conducted for both experimental and numerical pressure traces pointing out that LES well reproduces experimental knock tendencies.

Spectral Analysis of an Aeronautical Lean Direct Injection Burner Through Large Eddy Simulation

2020 ◽  
Author(s):  
M. Carreres ◽  
L. M. García-Cuevas ◽  
J. García-Tíscar ◽  
M. Belmar-Gil
Keyword(s):  
Experimental Data ◽  
Spectral Analysis ◽  
Flow Field ◽  
Large Eddy Simulation ◽  
Swirling Flow ◽  
Direct Injection ◽  
Flow Structures ◽  
Lean Direct Injection ◽  
Eddy Simulation ◽  
Large Eddy

Abstract During the last decades, many efforts have been invested by the scientific community in minimising exhaust emissions from aeronautical gas turbine engines. In this context, many advanced ultra-low NOx combustion concepts, such as the Lean Direct Injection treated in the present study, are being developed to abide by future regulations. Numerical simulations of these devices are usually computationally expensive since they imply a multi-scale problem. In this work, a non-reactive Large Eddy Simulation of a gaseous-fuelled, radial-swirled Lean-Direct Injection (LDI) combustor has been carried out through the OpenFOAM Computational Fluid Dynamics (CFD) code by solving the complete inlet flow path through the swirl vanes and the combustor. The geometry considered is the gaseous configuration of the CORIA LDI combustor, for which detailed measurements are available. Macroscopical analysis of the main turbulent features related to the swirling flow and the generated Central Recirculation Zone (CRZ) are well established in the literature. Nevertheless, a more in-depth characterization is still required in this area of active research since theory and experimental data are not yet able to predict which unstable mode dominates the flow. This work aims at using Large Eddy Simulation for a complete characterisation of the unsteady flow structures generated within the combustion chamber of a gaseous methane injection immersed in a strong non-reactive swirling flow field. To do so, a spectral analysis of the flow field is performed to identify the frequency, intensity and instabilities associated to the phenomena occurring at the swirler outlet region. A coherent structure known as Precessing Vortex Core (PVC) is identified both at the inner and the outer shear layers, resulting in a periodic disturbance of the pressure and velocity fields. The pressure and velocity fluctuations predicted by the CFD code are used to compute the spectral signatures through the Sound Pressure Level (SPL) amplitude at multiple locations. This allows investigating both the complex behaviour of the PVC and its associated acoustic phenomena. The acoustic characteristics computed by the numerical model are first validated qualitatively by comparing the spectrum with available experimental data. In this way, the use of dimensionless numbers to characterise the most energetic structures is coherent with the experimental observations and the characteristics of the PVC. Then, the numerical identification of the main acoustic modes in the chamber through Dynamic Mode Decomposition (DMD) allows overcoming the Fast Fourier Transform (FFT) shortcomings and better understanding the propagation of the hydrodynamic instability perturbations. This investigation on the main non-reacting swirling flow structures inside the combustor provides a suitable background for further studies on combustion instability mechanisms.

Spectral Analysis of an Aeronautical Lean Direct Injection Burner Through Large Eddy Simulation

2021 ◽  
Author(s):  
Marcos Carreres ◽  
Luis Miguel Garcia-Cuevas ◽  
Jorge Garc\xeda-T\xedscar ◽  
Mario Belmar
Keyword(s):  
Spectral Analysis ◽  
Large Eddy Simulation ◽  
Direct Injection ◽  
Lean Direct Injection ◽  
Eddy Simulation ◽  
Injection Burner ◽  
Large Eddy

Large-eddy simulation of the flow in a direct injection spark ignition engine using an open-source framework

2020 ◽  
pp. 146808742090362
Author(s):  
Mateus Dias Ribeiro ◽  
Alex Mendonça Bimbato ◽  
Maurício Araújo Zanardi ◽  
José Antônio Perrella Balestieri ◽  
David P Schmidt
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Large Eddy Simulation ◽  
Open Source ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Direct Injection Spark Ignition

Direct injection spark ignition engines aim at reducing specific fuel consumption and achieving the strict emission standards in state of the art internal combustion engines. This can be achieved by research comprising experimental methods, which are normally expensive and limited, and computational fluid dynamics methods, which are often more affordable and less restricted than their experimental counterpart. In the latter approach, the costs are mainly related to the acquisition, usage, and maintenance of computational resources, and the license cost when commercial computational fluid dynamics codes are used. Therefore, in order to make the research of direct injection spark ignition engines and their internal processes more accessible, this article proposes a novel open-source and free framework based on the OpenFOAM computational fluid dynamics library for the simulation of the internal flow in direct injection spark ignition engines using a large-eddy simulation closure for modeling the turbulence within the gas phase. Finally, this framework is tested by simulating the Darmstadt engine in motored operation, validating the results with experimental data compiled by the Darmstadt Engine Workshop.

scholarly journals Large-eddy simulation of methane direct injection using the full injector geometry

Fuel ◽  
2021 ◽  
Vol 290 ◽  
pp. 120019
Author(s):  
M.R. Yosri ◽  
J.Z. Ho ◽  
M. Meulemans ◽  
M. Talei ◽  
R.L. Gordon ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Direct Injection ◽  
Eddy Simulation ◽  
Large Eddy
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