CFD Modeling of Non-Premixed Combustion in a Gas Turbine Combustor

2002 ◽  
Author(s):  
Kitano Majidi
Keyword(s):  
Gas Turbine ◽  
Transport Model ◽  
Direct Injection ◽  
Turbulence Models ◽  
Cfd Modeling ◽  
Navier Stokes ◽  
Reacting Flow ◽  
Gas Temperature ◽  
Gas Turbine Combustor ◽  
Reynolds Stress Transport Model

In the present study numerical calculations are used to solve reacting flow in a gas turbine combustor. A 3-D Favre-Averaged Navier-Stokes solver for a mixture of chemically reacting gases is applied to predict the flow pattern, gas temperature and fuel and species concentrations in the entire combustor. The complete combustor geometry with all important details such as air swirler vane passages and secondary holes are modeled. The calculations are carried out using three different turbulence models. Comparisons are made between the standard k-ε model, RNG k-ε model and a Reynolds stress transport model. To provide a closure for the chemical source term the Eddy Dissipation model is used. A lean direct injection of a liquid fuel is employed. Furthermore the influence of radiation will be investigated.

A Comparison of Unsteady RANS Simulations With PIV Data in an Axial Turbomachine

2005 ◽  
Author(s):  
Daniel Brzozowski ◽  
Oguz Uzol ◽  
Yi-Chih Chow ◽  
Joseph Katz ◽  
Charles Meneveau
Keyword(s):  
Experimental Data ◽  
Transport Model ◽  
Energy Levels ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Piv Measurements ◽  
Flow Solver ◽  
Reynolds Stress Transport Model ◽  
Flow Features ◽  
Rans Simulations

This paper presents a comparison of 2D unsteady Reynolds Averaged Navier-Stokes (RANS) simulations using two standard turbulence models, i.e. RNG k-ε and a Reynolds Stress Transport Model, with experimental data, obtained using two-dimensional Particle Image Velocimetry (PIV) measurements within an entire stage of an axial turbomachine. The computations are performed using the commercial flow solver FLUENT™. A sliding mesh interface between the rotor and stator domains is used. The PIV measurements are performed in a refractive-index-matched facility that provides unobstructed view, and cover the entire 2nd stage of a two-stage axial pump. The inlet velocity and turbulence boundary conditions are provided from the experimental data. Detailed side-by-side comparisons of computed and measured phase-averaged velocity as well as turbulence fields within the entire stage are presented. Quantitative comparisons between the experiments and the computations are also included in terms of line distributions within the rotor-stator gap and the stator wake regions. The results show that, although there is reasonable agreement in general between the experimental results and the computational simulations, some critical flow features are not correctly predicted. The turbulent kinetic energy levels are generally too high in the simulations, with substantial amount of unphysical turbulence generation near the blade leading edges, especially in the case of RNG k-ε model.

Numerical Simulations of Low-Btu Coal Gas Combustion in a Gas Turbine Combustor

1991 ◽  
Author(s):  
Ajay K. Agrawal ◽  
Tah-Teh Yang
Keyword(s):  
Gas Turbine ◽  
Mixture Fraction ◽  
Flame Temperature ◽  
Three Dimensional ◽  
Reacting Flow ◽  
Gas Temperature ◽  
Gas Turbine Combustor ◽  
Gas Combustion ◽  
Complete Combustion ◽  
Coal Gas

A numerical model for turbulent reacting flow is described and applied for predictions in an industrial gas turbine combustor operating on low-Btu coal gas. The model, based on fast-reaction limit, used Favre averaged conservation equations with the standard k-ε model of turbulence. Effects of turbulent fluctuations on chemistry are described statistically in terms of the mean, variance and probability density function (assumed to be β-distribution) of the mixture fraction. Two types of geometric approximations, namely axisymmetric and three-dimensional, were used to model the combustor. Computations were performed with (a) no swirl (b) weak swirl and (c) strong swirl at the fuel and primary air inlets. Essentially, the same bulk mean temperature distributions were obtained for axisymmetric and three-dimensional calculations while the computed pattern factors and the liner wall temperatures for the two differed significantly. Complete combustion was predicted with strong swirl, a result supported by the available test data. The maximum liner wall temperature predicted for three-dimensional calculations compared favorably with the experimental data while the predicted maximum exhaust gas temperature differed by ≈120 K. The difference was attributed to measurement uncertainties, model assumptions and lack of accurate data at the inlets. The maximum flame temperature was below 1,850 K indicating that thermal NOx may be insignificant.

Numerical Simulation of Non-Reacting and Reacting Flows in a 5MW Commercial Gas Turbine Combustor

2009 ◽  
Author(s):  
Daero Jeong ◽  
Kang Y. Huh
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Measurement Data ◽  
Turbulence Models ◽  
Swirl Flow ◽  
Reacting Flows ◽  
Reacting Flow ◽  
Mean Flow ◽  
Gas Turbine Combustor ◽  
Swirl Flame

This study is concerned with numerical simulation of a simple swirl flame and a 5MW commercial gas turbine combustor both operating on methane/air. Validation is performed for turbulent flow and combustion models against some measurement data (http://public.ca.sandia.gov/TNF/swirlflames.html). Evaluation is performed for the standard k-e and the realizable k-e models in the nonreacting swirl flow and the EBU (eddy breakup) and the PPDF (presumed probability density function) models in the reacting flow of the 5 MW commercial combustor. Independent simulations are carried out for the main and pilot nozzles to avoid flashback and to provide realistic inflow boundary conditions for the combustor. Important geometrical details such as air swirlers, vane passages and liner holes are taken into account. Different turbulence models result in similar flow patterns with varying sizes of the recirculation pockets in the central region and at the outside corner. The EBU and the PPDF models show similar downstream distributions of mean flow and temperature, while the EBU shows a lifted flame with a stronger effect of swirl due to limited increase of axial momentum by volume expansion near the nozzle.

Combustion Dynamics Behavior in a Single-Element Lean Direct Injection (LDI) Gas Turbine Combustor

2014 ◽  
Author(s):  
Cheng Huang ◽  
Rohan Gejji ◽  
William Anderson ◽  
Changjin Yoon ◽  
Venkateswaran Sankaran
Keyword(s):  
Gas Turbine ◽  
Direct Injection ◽  
Single Element ◽  
Gas Turbine Combustor ◽  
Combustion Dynamics ◽  
Lean Direct Injection

Sensitization of the SST Turbulence Model to Rotation and Curvature by Applying the Spalart–Shur Correction Term

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Pavel E. Smirnov ◽  
Florian R. Menter
Keyword(s):  
Turbulent Flows ◽  
Turbulence Model ◽  
Transport Model ◽  
Correction Term ◽  
Computational Cost ◽  
Turbulence Models ◽  
Reynolds Stress Transport Model ◽  
Wide Range ◽  
Sst Model ◽  
The One

A rotation-curvature correction suggested earlier by Spalart and Shur (1997, “On the Sensitization of Turbulence Models to Rotation and Curvature,” Aerosp. Sci. Technol., 1(5), pp. 297–302) for the one-equation Spalart–Allmaras turbulence model is adapted to the shear stress transport model. This new version of the model (SST-CC) has been extensively tested on a wide range of both wall-bounded and free shear turbulent flows with system rotation and/or streamline curvature. Predictions of the SST-CC model are compared with available experimental and direct numerical simulations (DNS) data, on the one hand, and with the corresponding results of the original SST model and advanced Reynolds stress transport model (RSM), on the other hand. It is found that in terms of accuracy the proposed model significantly improves the original SST model and is quite competitive with the RSM, whereas its computational cost is significantly less than that of the RSM.

Bioethanol Combustion in an Industrial Gas Turbine Combustor: Simulations and Experiments

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Joost L. H. P. Sallevelt ◽  
Artur K. Pozarlik ◽  
Martin Beran ◽  
Lars-Uno Axelsson ◽  
Gerrit Brem
Keyword(s):  
Gas Turbine ◽  
Model Comparison ◽  
Reverse Flow ◽  
Operating Conditions ◽  
Fuel Spray ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Gas Turbine Combustor ◽  
Diffusion Type ◽  
Flamelet Model

Combustion tests with bioethanol and diesel as a reference have been performed in OPRA's 2 MWe class OP16 gas turbine combustor. The main purposes of this work are to investigate the combustion quality of ethanol with respect to diesel and to validate the developed CFD model for ethanol spray combustion. The experimental investigation has been conducted in a modified OP16 gas turbine combustor, which is a reverse-flow tubular combustor of the diffusion type. Bioethanol and diesel burning experiments have been performed at atmospheric pressure with a thermal input ranging from 29 to 59 kW. Exhaust gas temperature and emissions (CO, CO2, O2, NOx) were measured at various fuel flow rates while keeping the air flow rate and air temperature constant. In addition, the temperature profile of the combustor liner has been determined by applying thermochromic paint. CFD simulations have been performed with ethanol for five different operating conditions using ANSYS FLUENT. The simulations are based on a 3D RANS code. Fuel droplets representing the fuel spray are tracked throughout the domain while they interact with the gas phase. A liner temperature measurement has been used to account for heat transfer through the flame tube wall. Detailed combustion chemistry is included by using the steady laminar flamelet model. Comparison between diesel and bioethanol burning tests show similar CO emissions, but NOx concentrations are lower for bioethanol. The CFD results for CO2 and O2 are in good agreement, proving the overall integrity of the model. NOx concentrations were found to be in fair agreement, but the model failed to predict CO levels in the exhaust gas. Simulations of the fuel spray suggest that some liner wetting might have occurred. However, this finding could not be clearly confirmed by the test data.

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