Numerical Investigation of Enhanced Dilution Zone Mixing in a Reverse Flow Gas Turbine Combustor

1995 ◽  
Vol 117 (2) ◽  
pp. 272-281 ◽  
Author(s):  
D. S. Crocker ◽  
C. E. Smith
Keyword(s):  
Gas Turbine ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Turbulent Shear ◽  
Gas Turbine Combustor ◽  
Optimum Configuration ◽  
Average Temperature ◽  
Fuel Flow ◽  
Swirl Velocity ◽  
Radial Average

An advanced method for dilution zone mixing in a reverse flow gas turbine combustor was numerically investigated. For long mixing lengths associated with reverse flow combustors (X/H > 2.0), pattern factor was found to be mainly driven by nozzle-to-nozzle fuel flow and/or circumferential airflow variations; conventional radially injected dilution jets could not effectively mix out circumferential nonuniformities. To enhance circumferential mixing, dilution jets were angled to produce a high circumferential (swirl) velocity component. The jets on the outer liner were angled in one direction while the jets on the inner liner were angled in the opposite direction, thus enhancing turbulent shear at the expense of jet penetration. Three-dimensional CFD calculations were performed on a three-nozzle (90 deg) sector, with different fuel flow from each nozzle (90, 100, and 110 percent of design fuel flow). The computations showed that the optimum configuration of angled jets reduced the pattern factor by 60 percent compared to an existing conventional dilution hole configuration. The radial average temperature profile was adequately controlled by the inner-to-outer liner dilution flow split.

Numerical Investigation of Enhanced Dilution Zone Mixing in a Reverse Flow Gas Turbine Combustor

1993 ◽  
Author(s):  
D. Scott Crocker ◽  
Clifford E. Smith
Keyword(s):  
Gas Turbine ◽  
Reverse Flow ◽  
Turbulent Shear ◽  
Gas Turbine Combustor ◽  
Optimum Configuration ◽  
Average Temperature ◽  
Fuel Flow ◽  
Swirl Velocity ◽  
Hole Configuration ◽  
Radial Average

An advanced method for dilution zone mixing in a reverse flow gas turbine combustor was numerically investigated. For long mixing lengths associated with reverse flow combustors (X/H > 2.0), pattern factor was found to be mainly driven by nozzle-to-nozzle fuel flow and/or circumferential airflow variations; conventional radially injected dilution jets could not effectively mix out circumferential non-uniformities. To enhance circumferential mixing, dilution jets were angled to produce a high circumferential (swirl) velocity component. The jets on the outer liner were angled in one direction while the jets on the inner liner were angled in the opposite direction, thus enhancing turbulent shear at the expense of jet penetration. 3-D CFD calculations were performed on a three-nozzle (90°) sector, with different fuel flow from each nozzle (90%, 100% and 110% of design fuel flow). The computations showed that the optimum configuration of angled jets reduced the pattern factor by 60% compared to an existing conventional dilution hole configuration. The radial average temperature profile was adequately controlled by the inner-to-outer liner dilution flow split.

Pattern Factor Reduction in a Reverse Flow Gas Turbine Combustor Using Angled Dilution Jets

1994 ◽  
Author(s):  
D. Scott Crocker ◽  
Clifford E. Smith ◽  
Geoff D. Myers
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Reverse Flow ◽  
Gas Turbine Combustor ◽  
Temperature Variations ◽  
Average Temperature ◽  
Fuel Flow ◽  
Swirl Velocity ◽  
Hole Configuration ◽  
Radial Average

An advanced method for dilution zone mixing in reverse flow gas turbine combustors was experimentally investigated. To enhance circumferential mixing, dilution jets were injected with a high circumferential (swirl) velocity component. The jets on the outer liner were angled in one direction while the jets on the inner liner were angled in the opposite direction. To demonstrate reduced pattern factor, AlliedSignal Engines’ F109 combustor was tested at sea level takeoff conditions. For the baseline (conventional) configuration, the experimental results showed that large scale circumferential temperature non-uniformities at the turbine inlet were caused primarily by fuel flow variations from nozzle to nozzle. These temperature variations were significantly reduced by angled dilution jets. A pattern factor of 0.102 was achieved compared to the best case pattern factor of 0.163 for the baseline configuration. The only combustor modification was the dilution hole configuration. The radial average temperature profile produced by angled dilution jets was very similar to the profile produced by the baseline configuration.

Numerical investigation of flow in the liner of a model reverse-flow gas turbine combustor

2009 ◽  
Vol 223 (8) ◽  
pp. 1083-1090 ◽  
Author(s):  
M H Shojaeefard ◽  
K Ariafar ◽  
K Goudarzi
Keyword(s):  
Numerical Investigation ◽  
Gas Turbine ◽  
Turbulence Model ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Simple Algorithm ◽  
Staggered Grid ◽  
Gas Turbine Combustor ◽  
Model Studies

Designing a combustion chamber for a gas turbine engine requires expensive tests with many iterations. A numerical analysis can be employed to reduce the number of design iterations by providing an insight into the characteristics of the flow. This present article describes a three-dimensional numerical investigation of flow inside a model reverse-flow gas turbine combustor. In this computational work the entire model including the swirler has been selected for better accuracy. A finite volume non-staggered grid approach has been used and the pressure—velocity coupling is resolved using the SIMPLE algorithm. Comparisons are made between the standard k—ɛ turbulence model and the Reynolds stress turbulence model. Studies are performed to assess the velocity and pressure distributions at different locations in the combustor liner as well as the flow split through various holes on the liner surface. Overall, the predicted flow characteristics are found to be in reasonable agreement with the available experimental data.

scholarly journals Cold Flow Computations for the Diffuser-Combustor Section of an Industrial Gas Turbine

1996 ◽  
Author(s):  
Dadong Zhou ◽  
Ting Wang ◽  
William R. Ryan
Keyword(s):  
Gas Turbine ◽  
Total Pressure ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Complex Flow ◽  
Pressure Losses ◽  
Structured Grid ◽  
Computational Fluid Dynamics Cfd ◽  
Enhance Efficiency ◽  
Industrial Gas Turbine

In the first part of a multipart project to analyze and optimize the complex three-dimensional diffuser-combustor section of a highly advanced industrial gas turbine under development, a computational fluid dynamics (CFD) analysts has been conducted. The commercial FEA code I-DEAS was used to complete the three-dimensional solid modeling and the structured grid generation. The flow calculation was conducted using the commercial CFD code PHOENICS. The multiblock method was employed to enhance computational capabilities. The mechanisms of the total pressure losses and possible ways to enhance efficiency by reducing the total pressure losses were examined. Mechanisms that contribute to the nonuniform velocity distribution of flow entering the combustor were also identified. The CFD results were informative and provided insight to the complex flow patterns in the reverse flow dump diffuser, however, the results are qualitative and are useful primarily as guidelines for optimization as opposed to firm design configuration selections.

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.

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.

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.

Gas Turbine Combustor: Modelling and Optimization

2005 ◽  
Author(s):  
V. Ganesan ◽  
V. Jyothish Kumar
Keyword(s):  
Gas Turbine ◽  
Three Dimensional ◽  
Field Analysis ◽  
Gas Turbine Combustor ◽  
Cold Flow ◽  
Flow Losses ◽  
Flow Through ◽  
Flow Field Analysis ◽  
Probability Density Function Pdf ◽  
Modelling And Optimization

Present work is concerned with the flow field analysis inside an annular gas turbine combustor both under non-reacting and reacting conditions. Three-dimensional gas turbine combustor of 20-degree sector has been modeled using the pre-processor GAMBIT. Flow through the combustor has been simulated using FLUENT code by solving the appropriate governing equations viz., conservation of mass, momentum and energy. RNG κ-ε turbulence model is used for physical modeling. Initially prediffuser optimization has been carried out with respect to angle, length and contours. Flow through holes is modeled using porous jump boundary condition as well as modeling real holes themselves to study the efficacy of real hole modeling. Total pressure loss has been calculated to evaluate the cold flow as well as hot flow losses. Combustion has been modeled using the Probability Density Function (PDF) approach. Temperature and species concentrations are predicted.

Three-Dimensional CFD Analysis of a Gas Turbine Combustor for Medium/Low Heating Value Syngas Fuel

2008 ◽  
Author(s):  
Yan Xiong ◽  
Lucheng Ji ◽  
Zhedian Zhang ◽  
Yue Wang ◽  
Yunhan Xiao
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Coal Gasification ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Combined Cycle ◽  
Gas Turbine Combustor ◽  
Integrated Gasification Combined Cycle ◽  
Heating Value ◽  
Flamelet Model

Gas turbine is one of the key components for integrated gasification combined cycle (IGCC) system. Combustor of the gas turbine needs to burn medium/low heating value syngas produced by coal gasification. In order to save time and cost during the design and development of a gas turbine combustor for medium/low heating value syngas, computational fluid dynamics (CFD) offers a good mean. In this paper, 3D numerical simulations were carried out on a full scale multi-nozzle gas turbine combustor using commercial CFD software FLUENT. A 72 degrees sector was modeled to minimize the number of cells of the grid. For the fluid flow part, viscous Navier-Stokes equations were solved. The realizable k-ε turbulence model was adopted. Steady laminar flamelet model was used for the reacting system. The interaction between fluid turbulence and combustion chemistry was taken into account by the PDF (probability density function) model. The simulation was performed with two design schemes which are head cooling using film-cooling and impingement cooling. The details of the flow field and temperature distribution inside the two gas turbine combustors obtained could be cited as references for design and retrofit. Similarities were found between the predicted and experimental data of the transition duct exit temperature profile. There is much work yet to be done on modeling validation in the future.

Sign in / Sign up

Export Citation Format

Share Document