On the Prediction of Swirling Flowfields Found in Axisymmetric Combustor Geometries

1982 ◽  
Vol 104 (3) ◽  
pp. 378-384 ◽  
Author(s):  
D. L. Rhode ◽  
D. G. Lilley ◽  
D. K. McLaughlin
Keyword(s):  
Gas Turbine ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Boundary Representation ◽  
Reacting Flow ◽  
Gas Turbine Combustor ◽  
Turbine Engine ◽  
Research Activities ◽  
Gradual Expansion ◽  
Neutrally Buoyant

Combustor modeling has reached the stage where the most useful research activities are likely to be on specific sub-problems of the general three-dimensional turbulent reacting flow problem. The present study is concerned with a timely fluid dynamic research task of interest to the combustor modeling community. Numerical computations have been undertaken for a basic two-dimensional axisymmetric flowfield which is similar to that found in a conventional gas turbine combustor. A swirling nonreacting flow enters a larger chamber via a sudden or gradual expansion. The calculation method includes a stairstep boundary representation of the expansion flow, a conventional k-ε turbulence model and realistic accommodation of swirl effects. The results include recirculation zone characterization and predicted mean streamline patterns. In addition, an experimental evaluation using flow visualization of neutrally-buoyant helium-filled soap bubbles is yielding very promising results. Successful outcomes of the work can be incorporated into the more combustion- and hardware-oriented activities of gas turbine engine manufacturers, including incorporating the modeling aspects into already existing comprehensive numerical solution procedures.

Flow Investigations in an Aero Gas Turbine Engine Afterburner

2005 ◽  
Author(s):  
S. Suresh Kumar ◽  
V. Ganesan
Keyword(s):  
Gas Turbine ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Reacting Flow ◽  
Isothermal Model ◽  
Turbine Engine ◽  
Turbulence Effects ◽  
Dissipation Model ◽  
Volume Method

This paper is concerned with the prediction of flow and flame characteristics behind complex flame stabilizer used in aero gas turbine afterburners. The numerical calculation is performed using SIMPLE algorithm with unstructured grid arrangement in which time averaged transport equation for mass, momentum, turbulence and energy are solved using finite volume method. The turbulence effects are simulated using RNG κ-ε model. Flow analysis has been carried out for the non-reacting and reacting conditions. Meshing of the flow domain is done in GAMBIT. A detailed analysis of non-reacting flow in a 60°sector afterburner from inlet to exit of the afterburner is carried out in FLUENT solver code. The various thermodynamic properties are analyzed and presented along the length of the afterburner. Three different combustion models viz. prePDF, eddy dissipation and finite rate/eddy dissipation model are used in order to predict the reacting flow. An experimental investigation of the three-dimensional confined flow fields behind a “V” shaped complex flame stabilizer in an isothermal model of an afterburner is carried out to validate the CFD code. From the present study it is concluded that the prediction procedure adopted especially for non-reacting flow can be used with confidence in the development of an afterburner at a lower cost. Since measurements were not possible under reacting conditions no attempt has been made for reacting flow validation.

scholarly journals Modeling of marine gas turbine combustor under non-reacting and reacting conditions

1970 ◽  
Vol 2 (1) ◽  
pp. 21-32 ◽  
Author(s):  
V Jyothishkumar ◽  
V Ganesan
Keyword(s):  
Gas Turbine ◽  
Pressure Loss ◽  
Three Dimensional ◽  
Field Analysis ◽  
Recirculation Region ◽  
Reacting Flow ◽  
Gas Turbine Combustor ◽  
Flow Through ◽  
Flow Field Analysis ◽  
Marine Engineering

Present work is concerned with the flow field analysis inside a marine annular gas turbine combustor under non-reacting as well as reacting flow conditions. Three-dimensional gas turbine combustor of 20-degree sector geometry has been created and meshed 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. The RNG k-ε turbulence model is used for physical modeling. Combustion has been modeled using the Probability Density Function (PDF) approach. Total pressure loss has been studied for the isothermal as well as reacting flow case. For reacting flow overall pressure loss across the combustor has been evaluated. Keywords: Combustor, Recirculation region, Non-reacting flow. doi: 10.3329/jname.v2i1.2027 Journal of Naval Architecture and Marine Engineering 2(1)(2005) 21-32

scholarly journals Assessment of Combustor Working Environments

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Leiyong Jiang ◽  
Andrew Corber
Keyword(s):  
Gas Turbine ◽  
Operating Conditions ◽  
Reacting Flow ◽  
Gas Turbine Combustor ◽  
Two Phase ◽  
Turbine Engine ◽  
Working Environments ◽  
Flow Features ◽  
Critical Components ◽  
The Cost

In order to assess the remaining life of gas turbine critical components, it is vital to accurately define the aerothermodynamic working environments and service histories. As a part of a major multidisciplinary collaboration program, a benchmark modeling on a practical gas turbine combustor is successfully carried out, and the two-phase, steady, turbulent, compressible, reacting flow fields at both cruise and takeoff are obtained. The results show the complicated flow features inside the combustor. The airflow over each flow element of the combustor can or liner is not evenly distributed, and considerable variations, ±25%, around the average values, are observed. It is more important to note that the temperatures at the combustor can and cooling wiggle strips vary significantly, which can significantly affect fatigue life of engine critical components. The present study suggests that to develop an adequate aerothermodynamics tool, it is necessary to carry out a further systematic study, including validation of numerical results, simulations at typical engine operating conditions, and development of simple correlations between engine operating conditions and component working environments. As an ultimate goal, the cost and time of gas turbine engine fleet management must be significantly reduced.

scholarly journals Gas Turbine Combustor Development Tools for Production Designs

1985 ◽  
Author(s):  
Stephen N. Finger ◽  
Thomas L. Dubell
Keyword(s):  
Gas Turbine ◽  
Three Dimensional ◽  
Separated Flow ◽  
Preliminary Design ◽  
Trial And Error ◽  
Gas Turbine Combustor ◽  
Two Phase ◽  
Turbine Engine ◽  
Fundamental Knowledge ◽  
Black Art

Gas turbine engine combustor design and development has long held a somewhat undeserved reputation as a “Black Art”. This reputation was earned because those unfamiliar with the technology perceived the large amount of development testing required indicated a lack of fundamental knowledge of combustion. Fundamental knowledge exists and provides the foundation for design and to guide decisions on development. However, considerable trial and error work is required to satisfy many and sometimes conflicting performance goals because complete quantification of separated flow aerodynamics, three dimensional flowfields, anisotropic two phase flow, chemical reaction and heat addition is a challenge not yet met. Therefore, there is considerable reliance on use of rigs during the preliminary design phase and on the use of rigs and engines during development. Well founded use of experimental tools is necessary and must be adequately planned for in any program for a combustor intended for production. This paper describes these tools and how they should be used in such a program.

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.

Spectral and Timeresolved Radiation Measurements in a Model Gas Turbine Combustor

1994 ◽  
Author(s):  
R. Koch ◽  
W. Krebs ◽  
R. Jeckel ◽  
B. Ganz ◽  
S. Wittig
Keyword(s):  
Gas Turbine ◽  
Three Dimensional ◽  
Reacting Flow ◽  
Gas Turbine Combustor ◽  
Data Set ◽  
Time Resolved ◽  
Model Gas Turbine Combustor ◽  
Air Diffusion ◽  
First Time ◽  
Radiation Measurements

In the context of an extensive experimental investigation of the turbulent, reacting flow in a model gas turbine combustor, the radiation emitted by the confined three-dimensional turbulent propane/air diffusion-flame has been studied. The present study comprises for the first time spectral and time-resolved measurements of the radiative intensity at different axial locations including the reaction zone, the mixing zone and the exit of the model combustor. The radiation measurements are presented together with measurements and CFD-calculations characterizing the reacting flow field. This data set is well suited for the validation of CFD-calculations including radiative heat transfer and also for studying the interaction between turbulence and radiation.

scholarly journals Numerical Prediction of Non-Reacting and Reacting Flow in a Model Gas Turbine Combustor

2004 ◽  
Author(s):  
Farhad Davoudzadeh ◽  
Nan-Suey Liu
Keyword(s):  
Experimental Data ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Reacting Flow ◽  
Complex Flow ◽  
Gas Turbine Combustor ◽  
Model Gas Turbine Combustor

The three-dimensional, viscous, turbulent, reacting and non-reacting flow characteristics of a model gas turbine combustor operating on air/methane are simulated via an unstructured and massively parallel Reynolds-Averaged Navier-Stokes (RANS) code. This serves to demonstrate the capabilities of the code for design and analysis of real combustor engines. The effects of some design features of combustors are examined. In addition, the computed results are validated against experimental data. The numerical model encompasses the whole experimental flow passage, including the flow development sections for the air annulus and the fuel pipe, twelve channel air and fuel swirlers, the combustion chamber, and the tail pipe. A cubic non-linear low-Reynolds number K-e turbulence model is used to model turbulence, whereas the eddy-breakup model of Magnussen and Hjertager is used to account for the turbulence combustion interaction. Several RANS calculations are performed to determine the effects of the geometrical features of the combustor, and of the grid resolution on the flow field. The final grid is an all-hexahedron grid containing approximately two and one half million elements. To provide an inlet condition to the main combustion chamber, consistent with the experimental data, flow swirlers are adjusted along the flow delivery inlet passage. Fine details of the complex flow structure such as helicalring vortices, recirculation zones and vortex cores are well captured by the simulation. Consistent with the experimental results, the computational model predicts a major recirculation zone in the central region immediately downstream of the fuel nozzle, a second recirculation zone in the upstream corner of the combustion chamber, and a lifted flame. Further, the computed results predict the experimental data with reasonable accuracy for both the cold flow and for the reacting flow. It is also shown that small changes to the geometry can have noticeable effects on the combustor flowfield.

Performance Improvement of an Aero Gas Turbine Combustor

2009 ◽  
Author(s):  
M. Srinivasa Rao ◽  
G. Sivaramakrishna
Keyword(s):  
Gas Turbine ◽  
Performance Improvement ◽  
Three Dimensional ◽  
Gas Turbine Engine ◽  
Vital Role ◽  
Design Development ◽  
Gas Turbine Combustor ◽  
Specific Design ◽  
Turbine Engine ◽  
Dynamics Analyses

The HETD (Hot End Technologies Directorate) of GTRE (Gas Turbine Research Establishment) has the mandate of design, development and delivery of airworthy combustor and afterburner modules for a military aero gas turbine engine. In order to meet the mandate, the directorate takes the overall responsibility of design to manufacture of the combustion systems. Three-dimensional CFD (Computational Fluid Dynamics) analyses played a vital role in arriving at the final configuration meeting the specific design targets. This paper focuses on the utilization of the CFD code ‘Fluent’ in the successful realization of the main combustor of an aero gas turbine engine.

Large-Eddy Simulation of Reacting Turbulent Flows in Complex Geometries

2005 ◽  
Vol 73 (3) ◽  
pp. 374-381 ◽  
Author(s):  
K. Mahesh ◽  
G. Constantinescu ◽  
S. Apte ◽  
G. Iaccarino ◽  
F. Ham ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Flows ◽  
Reacting Flows ◽  
Gas Turbine Combustor ◽  
Turbine Engine ◽  
Progress Variable ◽  
Eddy Simulation ◽  
Variable Approach ◽  
Large Eddy

Large-eddy simulation (LES) has traditionally been restricted to fairly simple geometries. This paper discusses LES of reacting flows in geometries as complex as commercial gas turbine engine combustors. The incompressible algorithm developed by Mahesh et al. (J. Comput. Phys., 2004, 197, 215–240) is extended to the zero Mach number equations with heat release. Chemical reactions are modeled using the flamelet/progress variable approach of Pierce and Moin (J. Fluid Mech., 2004, 504, 73–97). The simulations are validated against experiment for methane-air combustion in a coaxial geometry, and jet-A surrogate/air combustion in a gas-turbine combustor geometry.

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