scholarly journals A New 0D Diesel HCCI Combustion Model Derived from a 3D CFD Approach with Detailed Tabulated Chemistry

2009 ◽  
Vol 64 (3) ◽  
pp. 259-284 ◽  
Author(s):  
A. Dulbecco ◽  
F.-A. Lafossas ◽  
G. Mauviot ◽  
T. J. Poinsot
Keyword(s):  
Combustion Model ◽  
Hcci Combustion ◽  
Tabulated Chemistry

scholarly journals Computational Modeling of Boundary Layer Flashback in a Swirling Stratified Flame Using a LES-Based Non-Adiabatic Tabulated Chemistry Approach

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 567
Author(s):  
Xudong Jiang ◽  
Yihao Tang ◽  
Zhaohui Liu ◽  
Venkat Raman
Keyword(s):  
Boundary Layer ◽  
Heat Loss ◽  
Boundary Layers ◽  
Gas Turbines ◽  
Predictive Accuracy ◽  
Safety Issue ◽  
Combustion Model ◽  
Tabulated Chemistry ◽  
Lean Fuel ◽  
Flame Flashback

When operating under lean fuel–air conditions, flame flashback is an operational safety issue in stationary gas turbines. In particular, with the increased use of hydrogen, the propagation of the flame through the boundary layers into the mixing section becomes feasible. Typically, these mixing regions are not designed to hold a high-temperature flame and can lead to catastrophic failure of the gas turbine. Flame flashback along the boundary layers is a competition between chemical reactions in a turbulent flow, where fuel and air are incompletely mixed, and heat loss to the wall that promotes flame quenching. The focus of this work is to develop a comprehensive simulation approach to model boundary layer flashback, accounting for fuel–air stratification and wall heat loss. A large eddy simulation (LES) based framework is used, along with a tabulation-based combustion model. Different approaches to tabulation and the effect of wall heat loss are studied. An experimental flashback configuration is used to understand the predictive accuracy of the models. It is shown that diffusion-flame-based tabulation methods are better suited due to the flashback occurring in relatively low-strain and lean fuel–air mixtures. Further, the flashback is promoted by the formation of features such as flame tongues, which induce negative velocity separated boundary layer flow that promotes upstream flame motion. The wall heat loss alters the strength of these separated flows, which in turn affects the flashback propensity. Comparisons with experimental data for both non-reacting cases that quantify fuel–air mixing and reacting flashback cases are used to demonstrate predictive accuracy.

scholarly journals Scale-Resolving Simulation of a Propane-Fuelled Industrial Gas Turbine Combustor Using Finite-Rate Tabulated Chemistry

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 126 ◽  
Author(s):  
Kai Zhang ◽  
Ali Ghobadian ◽  
Jamshid M. Nouri
Keyword(s):  
Gas Turbine ◽  
Chemical Reaction ◽  
Turbulent Flame ◽  
Lower Amount ◽  
Combustion Model ◽  
Gas Turbine Combustor ◽  
Finite Rate ◽  
Chemistry Method ◽  
Tabulated Chemistry ◽  
Partially Premixed

The scale-resolving simulation of a practical gas turbine combustor is performed using a partially premixed finite-rate chemistry combustion model. The combustion model assumes finite-rate chemistry by limiting the chemical reaction rate with flame speed. A comparison of the numerical results with the experimental temperature and species mole fraction clearly showed the superiority of the shear stress transport, K-omega, scale adaptive turbulence model (SSTKWSAS). The model outperforms large eddy simulation (LES) in the primary region of the combustor, probably for two reasons. First, the lower amount of mesh employed in the simulation for the industrial-size combustor does not fit the LES’s explicit mesh size dependency requirement, while it is sufficient for the SSTKWSAS simulation. Second, coupling the finite-rate chemistry method with the SSTKWSAS model provides a more reasonable rate of chemical reaction than that predicted by the fast chemistry method used in LES simulation. Other than comparing with the LES data available in the literature, the SSTKWSAS-predicted result is also compared comprehensively with that obtained from the model based on the unsteady Reynolds-averaged Navier–Stokes (URANS) simulation approach. The superiority of the SSTKWSAS model in resolving large eddies is highlighted. Overall, the present study emphasizes the effectiveness and efficiency of coupling a partially premixed combustion model with a scale-resolving simulation method in predicting a swirl-stabilized, multi-jets turbulent flame in a practical, complex gas turbine combustor configuration.

Enabling Air-Path Systems for Homogeneous Charge Compression Ignition (HCCI) Engine Transient Control

2009 ◽  
Author(s):  
Fengjun Yan ◽  
Junmin Wang
Keyword(s):  
Cost Effective ◽  
Combustion Model ◽  
Gas Temperature ◽  
Independent Control ◽  
Variable Geometry Turbocharger ◽  
Hcci Engine ◽  
Engine Simulation ◽  
Hcci Combustion ◽  
Transient Control ◽  
Path System

This paper explores the possibility of using a cost-effective air-path system that includes a dual-loop (exhaust gas recirculation) EGR and a (variable geometry turbocharger) VGT to achieve independent control of the main in-cylinder charge conditions (i.e. in-cylinder oxygen, inert gas amounts, and gas temperature at the intake valve closing) for HCCI engine combustion transient operation. An engine simulation model consisting of the air-path system and a HCCI combustion model was developed and synthesized to evaluate the control authority of the air-path system on the in-cylinder charge conditions as well as their effects on combustion. A variety of simulations unveiled that such an air-path system can enable independent control of the main in-cylinder charge conditions and active compensation of the effects of the wall temperature variations on HCCI combustion.

Prediction of Premixed Flame Dynamics Using Large Eddy Simulation With Tabulated Chemistry and Eulerian Stochastic Fields

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Alexander Avdonin ◽  
Alireza Javareshkian ◽  
Wolfgang Polifke
Keyword(s):  
Large Eddy Simulation ◽  
Time Series Data ◽  
Series Data ◽  
Combustion Model ◽  
Stochastic Fields ◽  
Progress Variable ◽  
Eddy Simulation ◽  
Flame Dynamics ◽  
Tabulated Chemistry ◽  
Large Eddy

Abstract This paper demonstrates that a large Eddy simulation (LES) combustion model based on tabulated chemistry and Eulerian stochastic fields can successfully describe the flame dynamics of a premixed turbulent swirl flame. The combustion chemistry is tabulated from one-dimensional burner-stabilized flamelet computations in dependence on progress variable and enthalpy. The progress variable allows to efficiently include a detailed reaction scheme, while the dependence on enthalpy describes the effect of heat losses on the reaction rate. The turbulence-chemistry interaction is modeled by eight Eulerian stochastic fields. An LES of a premixed swirl burner with a broadband velocity excitation is performed to investigate the flame dynamics, i.e., the response of heat release rate to upstream velocity perturbations. In particular, the flame impulse response and the flame transfer function (FTF) are identified from LES time series data. Simulation results for a range of power ratings are in good agreement with the experimental data.

A Methodology for Steady and Unsteady Full-Engine Simulations

2019 ◽  
Author(s):  
Luigi Romagnosi ◽  
Yingchen Li ◽  
Mohamed Mezine ◽  
Mateus Teixeira ◽  
Stephane Vilmin ◽  
...  
Keyword(s):  
High Speed ◽  
Compressible Flows ◽  
Stokes Equations ◽  
High Reliability ◽  
Combustion Process ◽  
Combustion Model ◽  
Cfd Models ◽  
Flamelet Generated Manifold ◽  
Tabulated Chemistry ◽  
Fully Coupled

Abstract With the increase of computational power, more sophisticated computational methods can be used, larger systems simulated, and complex phenomena predicted more reliably. Nevertheless, up to now, when turbomachinery systems are numerically optimized, each of the components, i.e., the compressor, combustor, and turbine, is simulated separately from the other two. While this approach allows the use of highly dedicated simulation tools, it does not account for the interactions between the different components. With the purpose to meet the future requirements in terms of low emissions, high reliability and efficiency, a novel, highly efficient, fully-coupled, approach based on the Reynolds-Averaged Navier-Stokes equations (RANS) has been developed, enabling a steady or time-accurate simulation of a full aero-engine within a single code. One of the advantages of a steady, fully coupled approach over a steady component-by-component approach, is that the boundary conditions at the interfaces do not need to be guessed. A fully coupled, time-accurate simulation has furthermore the advantage that the effect of the non-uniform temperature distribution at the outlet of the combustor is accounted for in the determination of the thermal field of the turbine. A Smart Interface methodology permits a direct coupling between the different engine components, compressor-combustor-turbine, and allows the Computational Fluid Dynamics (CFD) models to vary between each component within the same code. This allows the user to switch off, for instance, the combustion model in the turbine and compressor blocks. For the simulation of the combustion process, the Flamelet Generated Manifold (FGM) method is applied. While the approach is superior to classical tabulated chemistry approaches and reliably captures finite-rate effects, it is computationally inexpensive since it only requires the solution of a few extra scalars and the look-up of a combustion table. The model has been extended so that high-speed compressible flows can be simulated and the potential effects between the combustor and the adjacent blade rows can be accounted for. The Nonlinear Harmonic (NLH) method is used to model the unsteady interactions between the blade rows as well as the influence of the inhomogeneities at the combustor outlet on the downstream turbine blade rows. Compared to conventional time-accurate RANS simulations (URANS), this method is two to three orders of magnitude faster and makes time-accurate turbomachinery simulations affordable. With the aim of ensuring thermodynamic consistency between the different components of the engine, the same form of the energy equation is solved in all engine elements. Furthermore, the same thermodynamic coefficients, which are used to describe the reacting processes in the combustor, are used for a caloric description of the fluid in the compressor and turbine blocks. The thermodynamic data between the blocks is transferred using the OpenLabs™ module. The developed approach is described in detail and the potential of the novel full-engine methodology is exploited on the KJ66 micro-turbine gas engine case. The results of both the steady and the time-accurate, fully coupled approaches are analyzed and the interaction between the different components of the KJ66 engine discussed.

Application of Tabulated Detailed Chemistry to LES Model of Diesel ICE Combustion

2019 ◽  
Author(s):  
Oldrich Vitek ◽  
Vit Dolecek ◽  
Dmitry Goryntsev ◽  
Ferry Tap ◽  
Zoran Pavlovic ◽  
...  
Keyword(s):  
Predictive Ability ◽  
Industrial Applications ◽  
Computational Time ◽  
Combustion Model ◽  
Cfd Simulations ◽  
Detailed Chemistry ◽  
Tabulated Chemistry ◽  
Les Model ◽  
D Model ◽  
Fuel Surrogates

Abstract The use of 3-D CFD combustion models based on tabulated chemistry is becoming increasingly popular. Especially the runtime benefit is attractive, as the tabulated chemistry method allows including state-of-the-art chemical reaction schemes in CFD simulations without significant penalties in terms of computational time. In this work, the Tabkin FGM combustion model in AVL FIRE is used to perform LES simulations of a diesel ICE (AVL SCRE). Four load conditions are investigated with three different fuel surrogates. Predicted data are compared with reference ones (measurements or data from calibrated 0-D/1-D model) while discussing differences between them. CPU benefits are quantified. The main conclusion is that such CFD model has high predictive ability while requiring low calibration effort and being relatively fast, hence it is an interesting alternative to RANS-based industrial applications.

Large eddy simulation of an ignition sequence and the resulting steady combustion in a swirl-stabilized combustor using FGM-based tabulated chemistry

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Alain Fossi ◽  
Alain DeChamplain ◽  
Benjamin Akih-Kumgeh ◽  
Jeffrey Bergthorson
Keyword(s):  
Combustion Chamber ◽  
Combustion Regime ◽  
Flame Stabilization ◽  
Combustion Model ◽  
Content Type ◽  
Flame Kernel ◽  
Eddy Simulation ◽  
Tabulated Chemistry ◽  
Large Eddy ◽  
Steady Combustion

Purpose This study aims to deal with the large eddy simulation (LES) of an ignition sequence and the resulting steady combustion in a swirl-stabilized liquid-fueled combustor. Particular attention is paid to the ease of handling the numerical tool, the accuracy of the results and the reasonable computational cost involved. The primary aim of the study is to appraise the ability of the newly developed computational fluid dynamics (CFD) methodology to retrieve the spark-based flame kernel initiation, its propagation until the full ignition of the combustion chamber, the flame stabilization and the combustion processes governing the steady combustion regime. Design/methodology/approach The CFD model consists of an LES-based spray module coupled to a subgrid-scale ignition model to capture the flame kernel initiation and the early stage of the flame kernel growth, and a combustion model based on the mixture fraction-progress variable formulation in the line of the flamelet generated manifold (FGM) method to retrieve the subsequent flame propagation and combustion properties. The LES-spray module is based on an Eulerian-Lagrangian approach and includes a fully two-way coupling at each time step to account for the interactions between the liquid and the gaseous phases. The Wall-Adapting Local Eddy-viscosity (WALE) model is used for the flow field while the eddy diffusivity model is used for the scalar fluxes. The fuel is liquid kerosene, injected in the form of a polydisperse spray of droplets. The spray dynamics are tracked using the Lagrangian procedure, and the phase transition of droplets is calculated using a non-equilibrium evaporation model. The oxidation mechanism of the Jet A-1 surrogate is described through a reduced reaction mechanism derived from a detailed mechanism using a species sensitivity method. Findings By comparing the numerical results with a set of published data for a swirl-stabilized spray flame, the proposed CFD methodology is found capable of capturing the whole spark-based ignition sequence in a liquid-fueled combustion chamber and the main flame characteristics in the steady combustion regime with reasonable computing costs. Research limitations/implications The proposed CFD methodology simulates the whole ignition sequence, namely, the flame kernel initiation, its propagation to fully ignite the combustion chamber, and the global flame stabilization. Due to the lack of experimental ignition data on this liquid-fueled configuration, the ability of the proposed CFD methodology to accurately predict ignition timing was not quantitatively assessed. It would, therefore, be interesting to apply this CFD methodology to other configurations that have experimental ignition data, to quantitatively assess its ability to predict the ignition timing and the flame characteristics during the ignition sequence. Such further investigations will not only provide further validation of the proposed methodology but also will potentially identify its shortfalls for better improvement. Practical implications This CFD methodology is developed by customizing a commercial CFD code widely used in the industry. It is, therefore, directly applicable to practical configurations, and provides not only a relatively straightforward approach to predict an ignition sequence in liquid-fueled combustion chambers but also a robust way to predict the flame characteristics in the steady combustion regime as significant improvements are noticed on the prediction of slow species. Originality/value The incorporation of the subgrid ignition model paired with a combustion model based on tabulated chemistry allows reducing computational costs involved in the simulation of the ignition phase. The incorporation of the FGM-based tabulated chemistry provides a drastic reduction of computing resources with reasonable accuracy. The CFD methodology is developed using the platform of a commercial CFD code widely used in the industry for relatively straightforward applicability.

A Control-Oriented Charge Mixing and Two-Zone HCCI Combustion Model

2014 ◽  
Vol 63 (3) ◽  
pp. 1079-1090 ◽  
Author(s):  
Shupeng Zhang ◽  
Guoming Zhu ◽  
Zongxuan Sun
Keyword(s):  
Combustion Model ◽  
Hcci Combustion
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