scholarly journals Large eddy simulation of soot formation in a ducted fuel injection configuration

Fuel ◽  
2022 ◽  
Vol 313 ◽  
pp. 122735
Author(s):  
Jiun Cai Ong ◽  
Min Zhang ◽  
Morten Skov Jensen ◽  
Jens Honoré Walther
Keyword(s):  
Large Eddy Simulation ◽  
Fuel Injection ◽  
Soot Formation ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulation of fuel injection and mixing process in a diesel engine

2011 ◽  
Vol 27 (4) ◽  
pp. 519-530 ◽  
Author(s):  
Lei Zhou ◽  
Mao-Zhao Xie ◽  
Ming Jia ◽  
Jun-Rui Shi
Keyword(s):  
Diesel Engine ◽  
Large Eddy Simulation ◽  
Fuel Injection ◽  
Mixing Process ◽  
Eddy Simulation ◽  
Large Eddy

On the Combination of Large Eddy Simulation and Phenomenological Soot Modelling to Calculate the Smoke Index From Aero-Engines Over a Large Range of Operating Conditions

2017 ◽  
Author(s):  
Jean Lamouroux ◽  
Stéphane Richard ◽  
Quentin Malé ◽  
Gabriel Staffelbach ◽  
Antoine Dauptain ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbines ◽  
Soot Formation ◽  
Operating Conditions ◽  
Extended Model ◽  
Eddy Simulation ◽  
Design Office ◽  
Wide Range ◽  
Large Eddy ◽  
Aero Engines

Nowadays, models predicting soot emissions are, neither able to describe correctly fine effects of technological changes on sooting trends nor sufficiently validated at relevant operating conditions to match design office quantification needs. Yet, phenomenological descriptions of soot formation, containing key ingredients for soot modeling exist in the literature, such as the well-known Leung et al. model (Combust Flame 1991). This approach indeed includes contributions of nucleation, surface growth, coagulation, oxidation and thermophoretic transport of soot. When blindly applied to aeronautical combustors for different operating conditions, this model fails to hierarchize operating points compared to experimental measurements. The objective of this work is to propose an extension of the Leung model, including an identification of its constants over a wide range of condition relevant of gas turbines operation. Today, the identification process can hardly be based on laboratory flames since few detailed experimental data are available for heavy-fuels at high pressure. Thus, it is decided to directly target smoke number values measured at the engine exhaust for a variety of combustors and operating conditions from idling to take-off. A Large Eddy Simulation approach is retained for its intrinsic ability to reproduce finely unsteady behavior, mixing and intermittency. In this framework, The Leung model for soot is coupled to the TFLES model for combustion. It is shown that pressure-sensitive laws for the modelling constant of the soot surface chemistry are sufficient to reproduce engine emissions. Grid convergence is carried out to verify the robustness of the proposed approach. Several cases are then computed blindly to assess the prediction capabilities of the extended model. This study paves the way for the systematic use of a high fidelity tool solution in design office constraints for combustion chamber development.

scholarly journals Investigation of Flame Structure and Soot Formation in a Single Sector Model Combustor Using Experiments and Numerical Simulations Based on the Large Eddy Simulation/Conditional Moment Closure Approach

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Andrea Giusti ◽  
Epaminondas Mastorakos ◽  
Christoph Hassa ◽  
Johannes Heinze ◽  
Eggert Magens ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Soot Formation ◽  
Flame Structure ◽  
Moment Closure ◽  
Conditional Moment ◽  
Lean Burn ◽  
Eddy Simulation ◽  
Conditional Moment Closure ◽  
Soot Precursors ◽  
Large Eddy

In this work, a single sector lean burn model combustor operating in pilot only mode has been investigated using both experiments and computations with the main objective of analyzing the flame structure and soot formation at conditions relevant to aero-engine applications. Numerical simulations were performed using the large eddy simulation (LES) approach and the conditional moment closure (CMC) combustion model with detailed chemistry and a two-equation model for soot. The CMC model is based on the time-resolved solution of the local flame structure and allows to directly take into account the phenomena associated to molecular mixing and turbulent transport, which are of great importance for the prediction of emissions. The rig investigated in this work, called big optical single sector rig, allows to test real scale lean burn injectors. Experiments, performed at elevated pressure and temperature, corresponding to engine conditions at part load, include planar laser-induced fluorescence of OH (OH-PLIF) and phase Doppler anemometry (PDA) and have been complemented with new laser-induced incandescence (LII) measurements for soot location. The wide range of measurements available allows a comprehensive analysis of the primary combustion region and can be exploited to further assess and validate the LES/CMC approach to capture the flame behavior at engine conditions. It is shown that the LES/CMC approach is able to predict the main characteristics of the flame with a good agreement with the experiment in terms of flame shape, spray characteristics and soot location. Finite-rate chemistry effects appear to be very important in the region close to the injection location leading to the lift-off of the flame. Low levels of soot are observed immediately downstream of the injector exit, where a high amount of vaporized fuel is still present. Further downstream, the fuel vapor disappears quite quickly and an extended region characterized by the presence of pyrolysis products and soot precursors is observed. The strong production of soot precursors together with high soot surface growth rates lead to high values of soot volume fraction in locations consistent with the experiment. Soot oxidation is also very important in the downstream region resulting in a decrease of the soot level at the combustor exit. The results show a very promising capability of the LES/CMC approach to capture the main characteristics of the flame, soot formation, and location at engine relevant conditions. More advanced soot models will be considered in future work in order to improve the quantitative prediction of the soot level.

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