Assessment of the EDC combustion model in MILD conditions with in-furnace experimental data

2015 ◽  
Vol 75 ◽  
pp. 93-102 ◽  
Author(s):  
Delphine Lupant ◽  
Paul Lybaert
Keyword(s):  
Experimental Data ◽  
Combustion Model ◽  
Mild Conditions

Design Analysis of a Micro Gas Turbine Combustion Chamber Burning Natural Gas

2012 ◽  
Author(s):  
André Perpignan V. de Campos ◽  
Fernando L. Sacomano Filho ◽  
Guenther C. Krieger Filho
Keyword(s):  
Experimental Data ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Low Cost ◽  
Mixture Fraction ◽  
Combustion Model ◽  
Inlet Temperature ◽  
Gas Combustion ◽  
Micro Turbine

Gas turbines are reliable energy conversion systems since they are able to operate with variable fuels and independently from seasonal natural changes. Within that reality, micro gas turbines have been increasing the importance of its usage on the onsite generation. Comparatively, less research has been done, leaving more room for improvements in this class of gas turbines. Focusing on the study of a flexible micro turbine set, this work is part of the development of a low cost electric generation micro turbine, which is capable of burning natural gas, LPG and ethanol. It is composed of an originally automotive turbocompressor, a combustion chamber specifically designed for this application, as well as a single stage axial power turbine. The combustion chamber is a reversed flow type and has a swirl stabilized combustor. This paper is dedicated to the diagnosis of the natural gas combustion in this chamber using computational fluid dynamics techniques compared to measured experimental data of temperature inside the combustion chamber. The study emphasizes the near inner wall temperature, turbine inlet temperature and dilution holes effectiveness. The calculation was conducted with the Reynolds Stress turbulence model coupled with the conventional β-PDF equilibrium along with mixture fraction transport combustion model. Thermal radiation was also considered. Reasonable agreement between experimental data and computational simulations was achieved, providing confidence on the phenomena observed on the simulations, which enabled the design improvement suggestions and analysis included in this work.

scholarly journals Simulation of a GOx-GCH4 Rocket Combustor and the Effect of the GEKO Turbulence Model Coefficients

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 341
Author(s):  
Evgeny Strokach ◽  
Victor Zhukov ◽  
Igor Borovik ◽  
Andrej Sternin ◽  
Oscar J. Haidn
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Turbulence Model ◽  
Chemical Kinetic ◽  
Wall Heat Flux ◽  
Combustion Model ◽  
Combustion Chambers ◽  
Separation Parameter ◽  
Kinetic Mechanisms ◽  
Stable Performance

In this study, a single injector methane-oxygen rocket combustor is numerically studied. The simulations included in this study are based on the hardware and experimental data from the Technical University of Munich. The focus is on the recently developed generalized k–ω turbulence model (GEKO) and the effect of its adjustable coefficients on the pressure and on wall heat flux profiles, which are compared with the experimental data. It was found that the coefficients of ‘jet’, ‘near-wall’, and ‘mixing’ have a major impact, whereas the opposite can be deduced about the ‘separation’ parameter Csep, which highly influences the pressure and wall heat flux distributions due to the changes in the eddy-viscosity field. The simulation results are compared with the standard k–ε model, displaying a qualitatively and quantitatively similar behavior to the GEKO model at a Csep equal to unity. The default GEKO model shows a stable performance for three oxidizer-to-fuel ratios, enhancing the reliability of its use. The simulations are conducted using two chemical kinetic mechanisms: Zhukov and Kong and the more detailed RAMEC. The influence of the combustion model is of the same order as the influence of the turbulence model. In general, the numerical results present a good or satisfactory agreement with the experiment, and both GEKO at Csep = 1 or the standard k–ε model can be recommended for usage in the CFD simulations of rocket combustion chambers, as well as the Zhukov–Kong mechanism in conjunction with the flamelet approach.

Simulation of Methanol-Air Two-Phase Flames Using Various Turbulent Combustion Models

2009 ◽  
Author(s):  
F. Wang ◽  
Y. Huang ◽  
Y. Z. Wu
Keyword(s):  
Experimental Data ◽  
Turbulent Combustion ◽  
Turbulent Jet ◽  
Combustion Model ◽  
Air Flow Rate ◽  
Two Phase ◽  
Jet Flame ◽  
Combustion Simulation ◽  
Turbulent Combustion Model ◽  
Turbulent Models

Though fossil fuel is running out, liquid fuels nowadays still provide the most energy used by industrial furnaces, automotive and aero engines. How to predict a two-phase turbulent combustion flame is still a big problem to designers. Generally, the liquid fuel is sprayed and mixed with oxygen, and the flame characteristics depends on the fuel atomization, the fuel droplet spatial distribution, and its interaction with the turbulent oxidizer flow field: turbulent heat, mass and momentum transfer, complicated chemical kinetics, and turbulent-chemistry interaction. Turbulent combustion model is a key point for the two phase combustion simulation. For its short time consuming, Reynolds Averaged Navier Stokes (RANS) method nowadays still is the major tool for gas turbine chamber (GTC) designers, but there is not a universal method in RANS GTC spray combustion simulation at present especially for the two-phase turbulent combustion. The Eddy-Break-Up turbulent combustion model (EBU), Eddy Dissipation Concept turbulent combustion model (EDC), steady Laminar Flame-let turbulent combustion Model (LFM) and the Composition PDF transport turbulent combustion model (CPDF) are all widely used models. In this paper, these four turbulent models are used to simulate a methane-air turbulent jet flame measured by Sandia Lab first, then three methanol-air two-phase turbulent flames, in order to know the ability of these turbulent models. In the gas turbulent jet flame simulation, the result of LFM model and CPDF model are in better agreement with the experimental data than those of the EBU and the EDC models’ results. The reason is that the EBU model and EDC model are overestimated the effect of turbulent. In the three different cases of the two phase combustion simulation, CPDF is the best. The prediction ability of the other three models is different in different cases. The EDC predictions are closer to the experimental data when the air flow rate value is lower, whereas the LFM predictions are better when the air flow rate value is higher.

Development of a RANS Premixed Turbulent Combustion Model Based on the Algebraic Flame Surface Density Concept

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Usman Allauddin ◽  
Michael Pfitzner
Keyword(s):  
Experimental Data ◽  
Surface Density ◽  
Turbulent Flame ◽  
Theoretical Models ◽  
Elevated Pressure ◽  
Navier Stokes ◽  
Combustion Model ◽  
Flame Surface ◽  
Flame Surface Density ◽  
Premixed Turbulent Combustion

Recently, a fractal-based algebraic flame surface density (FSD) premixed combustion model has been derived and validated in the context of large eddy simulation (LES). The fractal parameters in the model, namely the cut-off scales and the fractal dimension were derived using theoretical models, experimental and direct numerical simulation (DNS) databases. The model showed good performance in predicting the premixed turbulent flame propagation for low to high Reynold numbers (Re) in ambient as well as elevated pressure conditions. Several LES combustion models have a direct counterpart in the Reynolds-averaged Navier–Stokes (RANS) context. In this work, a RANS version of the aforementioned LES subgrid scale FSD combustion model is developed. The performance of the RANS model is compared with that of the original LES model and validated with the experimental data. It is found that the RANS version of the model shows similarly good agreement with the experimental data.

Comparative Validation Study on Identification of Premixed Flame Transfer Function

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Luis Tay-Wo-Chong ◽  
Sebastian Bomberg ◽  
Ahtsham Ulhaq ◽  
Thomas Komarek ◽  
Wolfgang Polifke
Keyword(s):  
Experimental Data ◽  
Transfer Function ◽  
Turbulent Flame ◽  
Maximum Amplitude ◽  
Quantitative Agreement ◽  
Combustion Model ◽  
Reacting Flow ◽  
Phase Lag ◽  
Dynamics Simulations ◽  
The Impact

The flame transfer function (FTF) of a premixed swirl burner was identified from a time series generated with computational fluid dynamics simulations of compressible, turbulent, reacting flow at nonadiabatic conditions. Results were validated against experimental data. For large eddy simulation (LES), the dynamically thickened flame combustion model with one step kinetics was used. For unsteady simulation in a Reynolds-averaged Navier–Stokes framework (URANS), the Turbulent Flame Closure model was employed. The FTF identified from LES shows quantitative agreement with experiment for amplitude and phase, especially for frequencies below 200 Hz. At higher frequencies, the gain of the FTF is underpredicted. URANS results show good qualitative agreement, capturing the main features of the flame response. However, the maximum amplitude and the phase lag of the FTF are underpredicted. Using a low-order network model of the test rig, the impact of the discrepancies in predicted FTFs on frequencies and growth rates of the lowest order eigenmodes were assessed. Small differences in predicted FTFs were found to have a significant impact on stability limits. Stability behavior in agreement with experimental data was achieved only with the LES-based flame transfer function.

Comparative Validation Study on Identification of Premixed Flame Transfer Function

2011 ◽  
Author(s):  
Luis Tay-Wo-Chong ◽  
Sebastian Bomberg ◽  
Ahtsham Ulhaq ◽  
Thomas Komarek ◽  
Wolfgang Polifke
Keyword(s):  
Experimental Data ◽  
Transfer Function ◽  
Cfd Simulation ◽  
Turbulent Flame ◽  
Maximum Amplitude ◽  
Quantitative Agreement ◽  
Combustion Model ◽  
Reacting Flow ◽  
Phase Lag ◽  
The Impact

The flame transfer function (FTF) of a premixed swirl burner was identified from time series generated with CFD simulation of compressible, turbulent, reacting flow at non-adiabatic conditions. Results were validated against experimental data. For large eddy simulation (LES), the Dynamically Thickened Flame combustion model with one step kinetics was used. For unsteady simulation in a Reynolds-averaged Navier-Stokes framework (URANS), the Turbulent Flame Closure model was employed. The FTF identified from LES shows quantitative agreement with experiment for amplitude and phase, especially for frequencies below 200 Hz. At higher frequencies, the gain of the FTF is underpredicted. URANS results show good qualitative agreement, capturing the main features of the flame response. However, the maximum amplitude and the phase lag of the FTF are underpredicted. Using a low-order network model of the test rig, the impact of the discrepancies in predicted FTFs on frequencies and growth rates of the lowest order eigenmodes were assessed. Small differences in predicted FTFs were found to have a significant impact on stability limits. Stability behavior in agreement with experimental data was achieved only with the LES-based flame transfer function.

Investigation of Numerical Simulation in Combustion Chamber Predictability

2011 ◽  
Vol 317-319 ◽  
pp. 2085-2090
Author(s):  
Rang Shu Xu ◽  
Ling Niu ◽  
Xin Zhu Weng ◽  
Long Xu ◽  
Min Li Bai
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Combustion Chamber ◽  
Domain Boundary ◽  
Combustion Model ◽  
Physical Parameters ◽  
Computational Domain ◽  
Flame Tube ◽  
Vof Model ◽  
Adopted Model

For the purpose of increasing applicability of combustion chamber simulation, computational domain, boundary condition, simplicity of complicated structures, mesh generation and physical parameters are investigated in this paper. An annular combustion chamber of some aero-engine is studied by means of predictive numerical simulation. The computational domain includes diffuser, swirler, inner flame tube, inner ring of combustion chamber and the flow channel of all the holes on the wall of flame tube. The film cooling holes row was simplified into a slit filled with porous media. Realizable k-turbulent model and non-premixed combustion model were adopted. Model of pressure atomization nozzle were calibrated and validated through inner nozzle flow property two-phase flow VOF model and experimental data. Physical parameters are express through polynomial functions. A commercial CFD code was adopted on a high performance computing cluster with parallel algorithm and the solving method are high-order discretization scheme. The velocity, pressure, temperature, fuel spray, density of fuel and productions, etc. are calculated and validated with the experimental data.

Impact of Flame Stretch and Heat Loss on Heat Release Distributions in Gas Turbine Combustors: Model Comparison and Validation

2016 ◽  
Author(s):  
Noah Klarmann ◽  
Thomas Sattelmayer ◽  
Weiqun Geng ◽  
Benjamin Timo Zoller ◽  
Fulvio Magni
Keyword(s):  
Experimental Data ◽  
Heat Loss ◽  
Model Comparison ◽  
Turbulent Flame ◽  
Combustion Process ◽  
Combustion Model ◽  
Qualitative Comparison ◽  
Combustion Models ◽  
Flamelet Generated Manifold ◽  
Flame Stretch

The work presented in this paper comprises the application of an extension for the Flamelet Generated Manifold model which allows to consider elevated flame stretch rates and heat loss. This approach does not require further table dimensions. Hence, the numerical overhead is negligible, preserving the industrial applicability. A validation is performed in which stretch and heat loss dependent distributions are obtained from the combustion model to compare them to experimental data from an atmospheric single burner test rig operating at lean conditions. The reaction mechanism is extended by OH*-kinetics which allows the comparison of numerical OH*-concentrations with experimentally obtained OH*-chemiluminescence. Improvement compared to the Flamelet Generated Manifold model without extension regarding the shape and position of the turbulent flame brush can be shown and are substantiated by the validation of species distributions which better fit the experimental in situ measurements when the extension is used. These improvements are mandatory to enable subsequent modeling of emissions or thermoacoustics where high accuracy is required. In addition to the validation, a qualitative comparison of further combustion models is performed in which the experimental data serve as a benchmark to evaluate the accuracy. Most combustion models typically simplify the combustion process as flame stretch or non-adiabatic effects are not captured. It turns out that the tested combustion models show improvement when stretch or heat loss is considered by model corrections. However, satisfactory results could only be achieved by considering both effects employing the extension for the Flamelet Generated Manifold model.

Group Combustion of a Cylindrical Cloud of Char/Carbon Particles

1988 ◽  
Vol 110 (1) ◽  
pp. 190-200 ◽  
Author(s):  
K. Annamalai ◽  
S. Ramalingam ◽  
T. Dahdah ◽  
D. Chi
Keyword(s):  
Experimental Data ◽  
Collective Behavior ◽  
A Priori ◽  
Individual Particle ◽  
Combustion Model ◽  
Carbon Particles ◽  
Particle Combustion ◽  
Combustion Models ◽  
Coal Particles ◽  
Group Combustion

Extensive experiments were carried out in the past in order to obtain kinetics data on the pyrolysis of coal particles and the char reactions. The literature survey distinctively reveals two kinds of studies: (i) Individual Particle Combustion (IPC) and (ii) Combustion of Particle Streams or Clouds. The experimental data obtained with particle streams are normally interpreted using IPC models with the a priori assumption that the cloud is dilute. But the term “dilute” is rarely quantified and justified considering the collective behavior of a cloud of particles. The group combustion model accounts for the reduction in burning rate due to the collective behavior of a large number of particles. While the spherical group combustion model may be employed for coal/char spray combustion modeling, the cylindrical group combustion model is more useful in interpreting the experimental data obtained with a monosized stream of particles. Hence a cylindrical group combustion model is presented here. As in the case of spherical group combustion models, there exist three modes of combustion: (i) Individual Particle Combustion (IPC), (ii) Group Combustion (GC), and (iii) Sheath Combustion (SC). Within the range of parameters studied, it appears that the cylindrical and spherical cloud combustion models yield similar results on nondimensional cloud burning rates and on the combustion modes of a cloud of particles. The results from group theory are then used to identify the mode of combustion (IPC, GC, or SC) and to interpret the experimental data.

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