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 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.

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.

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.

scholarly journals Effect of Using Emulsions of High Nitrogen Containing Fuels and Water in a Gas Turbine Combustor on NOx and Other Emissions

1982 ◽  
Author(s):  
P. P. Singh ◽  
P. R. Mulik ◽  
A. Cohn
Keyword(s):  
Gas Turbine ◽  
Water Injection ◽  
High Water ◽  
Base Line ◽  
Gas Turbine Combustor ◽  
Fuel Flow ◽  
Unburned Hydrocarbons ◽  
Combustion Tests ◽  
Base Load ◽  
Test Fuel

A total of four combustion tests studying the response of various water/fuel emulsion rates on NOx emissions have been conducted on: (a) Paraho shale oil, (b) H-Coal© (372–522 K) distillate, (c) No. 2 oil doped with quinoline, (d) H-Coal© (505–616 K) distillate, utilizing a 0.14 m dia gas turbine can-type combustor at base-load conditions. Each test fuel run was proceeded with a base-line fuel run with No. 2 distillate oil. The results indicate that the effectiveness of water injection to reduce NOx decreased rapidly with an increase in the fuel-bound nitrogen (FBN) content of the test fuels. The smoke number, in general, decreased with increased water injection, while carbon monoxide and unburned hydrocarbons increased at high water/fuel flow rates.

scholarly journals A coupled flow and chemical reactor network model for predicting gas turbine combustor performance

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 1977-1989
Author(s):  
Seyfettin Hataysal ◽  
Ahmet Yozgatligil
Keyword(s):  
Gas Turbine ◽  
Network Model ◽  
Chemical Reactor ◽  
Gas Turbine Combustor ◽  
Actual Performance ◽  
Flow Network ◽  
Average Temperature ◽  
Chemical Reactor Network ◽  
Segregated Flow ◽  
Reactor Network

Gas turbine combustor performance was explored by utilizing a 1-D flow network model. To obtain the preliminary performance of combustion chamber, three different flow network solvers were coupled with a chemical reactor network scheme. These flow solvers were developed via simplified, segregated and direct solutions of the nodal equations. Flow models were utilized to predict the flow field, pressure, density and temperature distribution inside the chamber network. The network model followed a segregated flow and chemical network scheme, and could supply information about the pressure drop, nodal pressure, average temperature, species distribution, and flow split. For the verification of the model?s results, analyses were performed using CFD on a seven-stage annular test combustor from TUSAS Engine Industries, and the results were then compared with actual performance tests of the combustor. The results showed that the preliminary performance predictor code accurately estimated the flow distribution. Pressure distribution was also consistent with the CFD results, but with varying levels of conformity. The same was true for the average temperature predictions of the inner combustor at the dilution and exit zones. However, the reactor network predicted higher elemental temperatures at the entry zones.

CFD Analysis of Fuel Distribution in Concentric Swirling Flows in a Reverse Flow Gas Turbine Combustor

2006 ◽  
Author(s):  
K. Sudhakar Reddy ◽  
D. N. Reddy ◽  
C. M. Vara Prasad
Keyword(s):  
Gas Turbine ◽  
Reverse Flow ◽  
Distribution Patterns ◽  
Swirling Flows ◽  
Cfd Analysis ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Fuel Distribution ◽  
Wide Range ◽  
Injection Pressures

This paper presents the results of numerical investigations of a turbulent, swirling and recirculating flow without combustion inside a reverse flow gas turbine combustor. In order to establish the characteristics of fuel distribution patterns of the fuel spray injected into swirling flows, flow fields are analyzed inside the swirl combustor for varying amount of swirl strength using a commercial CFD code fluent 6.1.22. Three Dimensional computations are performed to study the influence of the various parameters like injection pressure, flow Reynolds number and Swirl Strength on the fuel distribution patterns. The model predictions are compared against the experimental results, and its applicability over a wide range of flow conditions was investigated. It was observed from the CFD analysis, that the fuel decay along the axis is faster with low injection pressures compared to higher injection pressures. With higher Reynolds numbers the fuel patterns are spreading longer in the axial direction. The higher momentum of the air impedes the radial mixing and increases the constraint on the jet spread. The results reveal that an increase in swirl enhances the mixing rate of the fuel and air and causes recirculation to be more pronounced and to occur away form the fuel injector. The CFD predictions are compared with the experimental data from the phototransistor probe measurements, and good agreement has been achieved.

Resolving Large- and Small-Scale Structures in the Swirl Flow of a Typical Land-Based Gas Turbine Combustor Single Nozzle Rig

2014 ◽  
Author(s):  
R. K. R. Katreddy ◽  
S. R. Chakravarthy
Keyword(s):  
Velocity Field ◽  
Gas Turbine ◽  
Large Scale ◽  
Recirculation Zone ◽  
Laser Diagnostics ◽  
Swirl Flow ◽  
Sudden Expansion ◽  
Small Scale ◽  
Gas Turbine Combustor ◽  
Scale Structures

The present study focuses on identifying and resolving large-scale energy containing structures and turbulent eddies in a typical gas turbine combustor single nozzle rig, using particle image velocimetry in cold flow. A generic fuel-air nozzle through a swirler is integrated with a sudden expansion square duct with optical access to perform laser diagnostics. Experiments are conducted to analyze the swirl flow field under starting and operating flow conditions. Three-component velocities are obtained in cross-sectional planes of Z/D = 0, 1.25, and 2.5 (normalized by the nozzle diameter), and two-component velocities are obtained in the mid-plane along the longitudinal (Z-) axis from Z/D = 0 to 2.5D. Velocity splitting is performed using spatial Gaussian smoothing with a kernel with filter width equal to integral scale is performed over the velocity fields to resolve the field of large-scale energy containing eddies. Proper orthogonal decomposition is performed over the large-scale velocity field, and the modes obtained indicate the existence of the precessing vortex core (PVC), formation of small scales Kelvin-Helmholtz (K-H) vortices for Z/D < 1.25D, and large-scale growing K-H structures in 1.25D < Z/D < 2.5D. Turbulent kinetic energy (TKE) is obtained from the turbulent velocity fluctuations below the integral length scale and is observed to be higher at the interface of the corner recirculation zone (CRZ) and central toroidal recirculation zone (CTRZ). Resolving the swirl velocity field obtained in the above manner into large-scale structures formed by the PVC, CTRZ, K-H vortices, CRZ, and small-scale turbulence field, indicates the clear distinction in rapid mixing zones and unsteady convective zones. The length-scales and zones of these structures within the swirl combustor are identified.

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