Coupled Lagrangian Monte Carlo PDF–CFD Computation of Gas Turbine Combustor Flowfields With Finite-Rate Chemistry

1997 ◽  
Vol 119 (3) ◽  
pp. 519-526 ◽  
Author(s):  
A. K. Tolpadi ◽  
I. Z. Hu ◽  
S. M. Correa ◽  
D. L. Burrus
Keyword(s):  
Monte Carlo ◽  
Gas Turbine ◽  
Bluff Body ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Gas Turbine Combustor ◽  
Finite Rate ◽  
Reduced Chemistry ◽  
Rate Effects ◽  
Fast Chemistry

A coupled Lagrangian Monte Carlo Probability Density Function (PDF)-Eulerian Computational Fluid Dynamics (CFD) technique is presented for calculating steady three-dimensional turbulent reacting flow in a gas turbine combustor. PDF transport methods model turbulence-combustion interactions more accurately than conventional turbulence models with an assumed shape PDF. The PDF transport equation was solved using a Lagrangian particle tracking Monte Carlo (MC) method. The PDF modeled was over composition only. This MC module has been coupled with CONCERT, which is a fully elliptic three-dimensional body-fitted CFD code based on pressure correction techniques. In an earlier paper (Tolpadi et al., 1995), this computational approach was described, but only fast chemistry calculations were presented in a typical aircraft engine combustor. In the present paper, reduced chemistry schemes were incorporated into the MC module that enabled the modeling of finite rate effects in gas turbine flames and therefore the prediction of CO and NOx emissions. With the inclusion of these finite rate effects, the gas temperatures obtained were also more realistic. Initially, a two scalar scheme was implemented that allowed validation against Raman data taken in a recirculating bluff body stabilized CO/H2/N2-air flame. Good agreement of the temperature and major species were obtained. Next, finite rate computations were performed in a single annular aircraft engine combustor by incorporating a simple three scalar reduced chemistry scheme for Jet A fuel. This three scalar scheme was an extension of the two scalar scheme for CO/H2/N2 fuel. The solutions obtained using the present approach were compared with those obtained using the fast chemistry PDF transport approach (Tolpadi et al., 1995) as well as the presumed shape PDF method. The calculated exhaust gas temperature using the finite rate model showed the best agreement with measurements made by a thermocouple rake. In addition, the CO and NOx emission indices were also computed and compared with corresponding data.

scholarly journals Coupled Lagrangian Monte Carlo PDF–CFD Computation of Gas Turbine Combustor Flowfields With Finite–Rate Chemistry

1996 ◽  
Author(s):  
Anil K. Tolpadi ◽  
Iris Z. Hu ◽  
Sanjay M. Correa ◽  
David L. Burrus
Keyword(s):  
Monte Carlo ◽  
Gas Turbine ◽  
Bluff Body ◽  
Aircraft Engine ◽  
Reacting Flow ◽  
Gas Turbine Combustor ◽  
Finite Rate ◽  
Reduced Chemistry ◽  
Rate Effects ◽  
Fast Chemistry

A coupled Lagrangian Monte Carlo Probability Density Function (PDF)–Eulerian Computational Fluid Dynamics (CFD) technique is presented for calculating steady three–dimensional (3–D) turbulent reacting flow in a gas turbine combustor. PDF transport methods model turbulence–combustion interactions more accurately than conventional turbulence models with an assumed shape PDF. The PDF transport equation was solved using a Lagrangian particle tracking Monte Carlo (MC) method. The PDF modeled was over composition only. This MC module has been coupled with CONCERT, which is a fully elliptic 3–D body–fitted CFD code based on pressure correction techniques. In an earlier paper [Tolpadi et al, 1995], this computational approach was described but only fast chemistry calculations were presented in a typical aircraft engine combustor. In the present paper, reduced chemistry schemes were incorporated into the MC module that enabled the modeling of finite rate effects in gas turbine flames and therefore the prediction of CO and NOx emissions. With the inclusion of these finite rate effects, the gas temperatures obtained were also more realistic. Initially, a two scalar scheme was implemented that allowed validation against Raman data taken in a recirculating bluff body stabilized CO/H2/N2–air flame. Good agreement of the temperature and major species were obtained. Next, finite rate computations were performed in a single annular aircraft engine combustor by incorporating a simple three scalar reduced chemistry scheme for Jet A fuel. This three scalar scheme was an extension of the two scalar scheme for CO/H2/N2 fuel. The solutions obtained using the present approach were compared with those obtained using the fast chemistry PDF transport approach [Tolpadi et al, 1995] as well as the presumed shape PDF method. The calculated exhaust gas temperatures using the finite rate model showed the best agreement with measurements made by a thermocouple rake. In addition, the CO and NOx emission indices were also computed and compared with corresponding data.

Analysis of the Heat Transfer within combustor liners Using a Combined Monte Carlo and two-flux method

2021 ◽  
pp. 1-25
Author(s):  
Andressa Johnson ◽  
Xinyu Zhao
Keyword(s):  
Monte Carlo ◽  
Gas Turbine ◽  
Radiation Treatment ◽  
Three Dimensional ◽  
Radiative Energy ◽  
Gas Turbine Combustor ◽  
Eddy Simulation ◽  
Elevated Pressures ◽  
Large Eddy ◽  
Model Gas Turbine Combustor

Abstract One consequence of increasing efficiency of gas turbine combustors is higher temperatures within the combustor. Management of larger heat load has been advanced to protect the combustor wall and turbines, and among those are thermal barrier coatings (TBCs). Historically, both the flame and TBCs have received a simplified radiation treatment using effective absorptivities and emissivities. In this study, non-gray radiation is compared to gray and black radiation by combining three-dimensional Monte Carlo Ray Tracing solution of non-gray flames in a model gas turbine combustor to one-dimensional energy balance within combustor liners. A recent large eddy simulation of a gas turbine combustor is analyzed, where both gray and non-gray models are exercised. A two-band spectral model is employed for the TBC, where a translucent band and an opaque band are identified. A line-by-line treatment for gas-phase radiation is adopted, and the incident radiative energy on the combustor wall is collected using the MCRT solver, where the fraction of radiative energy within the translucent band is collected and compared with those obtained from the blackbody assumption. The temperature along the multi-layered combustor wall is computed and parametric comparison is conducted. The effects of the nongray flame radiation are more prominent at elevated pressures than at atmospheric pressure. The gray model is found to over-predict the TBC temperature, which leads to a difference of approximately 150 K in the prediction of peak temperature on the hot side of the TBC.

Analysis of the Heat Transfer Within Combustor Liners Using a Combined Monte Carlo and Two-Flux Method

2020 ◽  
Author(s):  
Andressa L. Johnson ◽  
Xinyu Zhao
Keyword(s):  
Monte Carlo ◽  
Gas Turbine ◽  
Three Dimensional ◽  
Radiative Energy ◽  
Air Cooling ◽  
Gas Turbine Combustor ◽  
Eddy Simulation ◽  
Model Gas Turbine Combustor ◽  
Forced Air ◽  
Cold Metal

Abstract One of the consequences of increasing the efficiency of gas turbine combustors is the higher combustion temperatures within the chamber. Advances on managing larger heat loads have been made to protect the combustor wall and turbines. Among those are thermal barrier coatings (TBCs) deposited on metal walls and forced air cooling such as through effusion holes. Historically, both the flame and TBCs have received a simplified gray treatment using effective absorptivities and emissivities. However, studies have shown that the gray analysis can considerably under-predict the cold metal side temperature resulting in misguided combustor life estimates. In this study, non-gray radiation is compared to gray and black radiation by combining three-dimensional Monte Carlo Ray Tracing (MCRT) solution of non-gray flames in a model gas turbine combustor to one-dimensional energy balance within combustor liners. A recent large eddy simulation (LES) of a gas turbine combustor is analyzed, where both gray and non-gray models are exercised. A two-band spectral model is employed for the TBC, where a translucent band and an opaque band are identified. A line-by-line treatment for gas-phase radiation is adopted, and the incident radiative energy on the combustor wall is collected using the MCRT solver, where the fraction of radiative energy within the translucent band is collected and compared with those obtained from the blackbody assumption. The temperature distributions along the multi-layered combustor wall are computed and parametric comparison is conducted. The effects of the nongray flame radiation are more prominent at elevated pressures than at atmospheric pressure, leading to a difference of approximately 150 K in the prediction of peak temperature on the hot side of the TBC. The gray model is found to over-predict the TBC temperature at downstream locations, but under-predict the TBC temperature near the flame locations. The present study proposes a methodology to estimate the wall temperatures when radiation within the TBC is considered. Future work includes application of the methodology to more realistic combustors where both radiative fluxes and convective fluxes can be accurately captured.

Combustion Technology for Low-Emissions Gas-Turbines: Some Recent Modeling Results

1996 ◽  
Vol 118 (3) ◽  
pp. 201-208 ◽  
Author(s):  
S. M. Correa ◽  
I. Z. Hu ◽  
A. K. Tolpadi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Spectroscopic Data ◽  
Physical Models ◽  
Gas Turbine Combustor ◽  
Finite Rate ◽  
Recent Developments ◽  
Combustion Technology ◽  
Computationally Intensive ◽  
Transport Method

Computer modeling of low-emissions gas-turbine combustors requires inclusion of finite-rate chemistry and its intractions with turbulence. The purpose of this review is to outline some recent developments in and applications of the physical models of combusting flows. The models reviewed included the sophisticated and computationally intensive velocity-composition pdf transport method, with applications shown for both a laboratory flame and for a practical gas-turbine combustor, as well as a new and computationally fast PSR-microstructure-based method, with applications shown for both premixed and nonpremixed flames. Calculations are compared with laserbased spectroscopic data where available. The review concentrates on natural-gas-fueled machines, and liquid-fueled machines operating at high power, such that spray vaporization effects can be neglected. Radiation and heat transfer is also outside the scope of this review.

Predicting Thermoacoustic Instability in an Industrial Gas Turbine Combustor: Combining a Low Order Network Model With Flame LES

2017 ◽  
Author(s):  
Y. Xia ◽  
A. S. Morgans ◽  
W. P. Jones ◽  
J. Rogerson ◽  
G. Bulat ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Acoustic Waves ◽  
Gas Turbine Combustor ◽  
Network Modelling ◽  
Weakly Nonlinear ◽  
Thermoacoustic Instability ◽  
Reduced Chemistry ◽  
Flame Describing Function ◽  
Industrial Gas Turbine ◽  
Low Order

The thermoacoustic modes of a full scale industrial gas turbine combustor have been predicted numerically. The predictive approach combines low order network modelling of the acoustic waves in a simplified geometry, with a weakly nonlinear flame describing function, obtained from incompressible large eddy simulations of the flame region under upstream forced velocity perturbations, incorporating reduced chemistry mechanisms. Two incompressible solvers, each employing different numbers of reduced chemistry mechanism steps, are used to simulate the turbulent reacting flowfield to predict the flame describing functions. The predictions differ slightly between reduced chemistry approximations, indicating the need for more involved chemistry. These are then incorporated into a low order thermoacoustic solver to predict thermoacoustic modes. For the combustor operating at two different pressures, most thermoacoustic modes are predicted to be stable, in agreement with the experiments. The predicted modal frequencies are in good agreement with the measurements, although some mismatches in the predicted modal growth rates and hence modal stabilities are observed. Overall, these findings lend confidence in this coupled approach for real industrial gas turbine combustors.

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.

Monte Carlo Probability Density Function Method for Gas Turbine Combustor Flowfield Predictions

1997 ◽  
Vol 13 (2) ◽  
pp. 218-225 ◽  
Author(s):  
Anil K. Tolpadi ◽  
Sanjay M. Correa ◽  
David L. Burrus ◽  
Hukam C. Mongia
Keyword(s):  
Monte Carlo ◽  
Probability Density Function ◽  
Probability Density ◽  
Gas Turbine ◽  
Density Function ◽  
Function Method ◽  
Gas Turbine Combustor

Three-Dimensional Computation of Gas Turbine Combustors and the Validation Studies of Turbulence and Combustion Models

1997 ◽  
Author(s):  
D. Biswas ◽  
K. Kawano ◽  
H. Iwasaki ◽  
M. Ishizuka ◽  
S. Yamanaka
Keyword(s):  
Gas Turbine ◽  
Validation Studies ◽  
Three Dimensional ◽  
Chemical Species ◽  
Reaction Rates ◽  
Reacting Flows ◽  
Gas Turbine Combustor ◽  
Combustion Models ◽  
Rate Of Dissipation

The main aim or the present work is to explore computational fluid dynamics and related turbulence and combustion models for application to the design, understanding and development of gas turbine combustor. Validation studies were conducted using the Semi-Implicit Method for Pressure Linked Equations (SIMPLE) scheme to solve the relevant steady, elliptical partial differential equations of the conservation of mass, momentum, energy and chemical species in three-dimensional cylindrical co-ordinate system to simulate the gas turbine combustion chamber configurations. A modified version of k-ε turbulence model was used for characterization of local turbulence in gas turbine combustor. Since, in the present study both diffusion and pre-mixed combustion were considered, in addition to familiar bi-molecular Arhenius relation, influence of turbulence on reaction rates was accounted for based on the eddy break up concept of Spalding and was assumed that the local reaction rate was proportional to the rate of dissipation of turbulent eddies. Firstly, the validity of the present approach with the turbulence and reaction models considered is checked by comparing the computed results with the standard experimental data on recirculation zone, mean axial velocity and temperature profiles, etc. for confined, reacting and non-reacting flows with reasonably well defined boundary conditions. Finally, the results of computation for practical gas turbine combustor using combined diffusion and pre-mixed combustion for different combustion conditions are discussed.

Thermoacoustic Modeling of a Gas Turbine Combustor Equipped With Acoustic Dampers

2005 ◽  
Vol 127 (2) ◽  
pp. 372-379 ◽  
Author(s):  
Valter Bellucci ◽  
Bruno Schuermans ◽  
Dariusz Nowak ◽  
Peter Flohr ◽  
Christian Oliver Paschereit
Keyword(s):  
Transfer Function ◽  
Gas Turbine ◽  
Mixture Fraction ◽  
Time Lag ◽  
Multiple Input Multiple Output ◽  
Three Dimensional ◽  
Analytical Models ◽  
Gas Turbine Combustor ◽  
Input Multiple Output ◽  
The Time Domain

In this work, the TA3 thermoacoustic network is presented and used to simulate acoustic pulsations occurring in a heavy-duty ALSTOM gas turbine. In our approach, the combustion system is represented as a network of acoustic elements corresponding to hood, burners, flames and combustor. The multi-burner arrangement is modeled by describing the hood and combustor as Multiple Input Multiple Output (MIMO) acoustic elements. The MIMO transfer function (linking acoustic pressures and acoustic velocities at burner locations) is obtained by a three-dimensional modal analysis performed with a Finite Element Method. Burner and flame analytical models are fitted to transfer function measurements. In particular, the flame transfer function model is based on the time-lag concept, where the phase shift between heat release and acoustic pressure depends on the time necessary for the mixture fraction (formed at the injector location) to be convected to the flame. By using a state-space approach, the time domain solution of the acoustic field is obtained. The nonlinearity limiting the pulsation amplitude growth is provided by a fuel saturation term. Furthermore, Helmholtz dampers applied to the gas turbine combustor are acoustically modeled and included in the TA3 model. Finally, the predicted noise reduction is compared to that achieved in the engine.

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