Flow Field Derived Equivalent Reactor Networks for Accurate Chemistry Simulation in Gas Turbine Combustors

2009 ◽  
Author(s):  
Scott A. Drennan ◽  
Chen-Pang Chou ◽  
Anthony F. Shelburn ◽  
Devin W. Hodgson ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Flame Structure ◽  
Cost Effective ◽  
Fuel Injector ◽  
Accurate Analysis ◽  
Detailed Chemistry ◽  
Reactor Networks ◽  
Detailed Kinetics ◽  
Time Required

A method has been developed in which the flow field predicted by Computational Fluid Dynamics (CFD) is automatically condensed into an Equivalent Reactor Network (ERN), composed of well stirred reactors, allowing rapid and accurate analysis of emissions. This paper presents the effectiveness of utilizing an ERN that is a direct abstraction of the computational flow field for combustion analysis. The CFD results are divided into reactors using various filters on flow-field variables to construct an ERN that represents the 3-D combustor flow field and flame structure. Detailed kinetics can then be used in ERN simulations to analyze effects of fuel composition and operating condition on emissions. The technique is applied to a commercial industrial gas turbine combustor fuel injector and compared against experimental emissions results. Sensitivity of emissions predictions to different parameters in the network extraction is also presented. Parameter variations in fuel flow rate are applied to the ERN to obtain relative impacts of fuel-air ratio on the emissions of NOx without requiring new CFD solutions. This automatic approach has been found to reduce the time required to construct and analyze flow field derived ERNs with detailed chemistry by 90%. A local calculation of Damko¨hler number, important for stability analysis, is also presented. This calculation also uses abstracted information from the CFD flow field and detailed-kinetics simulations for more accurate, cost-effective analysis.

Spray Flame Study Using a Model Gas Turbine Swirl Burner

2013 ◽  
Vol 316-317 ◽  
pp. 17-22 ◽  
Author(s):  
Cheng Tung Chong ◽  
Simone Hochgreb
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Flame Structure ◽  
Fuel Droplets ◽  
Spray Flame ◽  
Spray Flames ◽  
Reaction Zones ◽  
Fixed Power ◽  
Particle Imaging ◽  
Gas Turbine Burner

A model gas turbine burner was employed to investigate spray flames established under globally lean, continuous, swirling conditions. Two types of fuel were used to generate liquid spray flames: palm biodiesel and Jet-A1. The main swirling air flow was preheated to 350 °C prior to mixing with airblast-atomized fuel droplets at atmospheric pressure. The global flame structure of flame and flow field were investigated at the fixed power output of 6 kW. Flame chemiluminescence imaging technique was employed to investigate the flame reaction zones, while particle imaging velocimetry (PIV) was utilized to measure the flow field within the combustor. The flow fields of both flames are almost identical despite some differences in the flame reaction zones.

The Impact of Representative Aerodynamic Flow Fields on Liquid Fuel Atomisation in Modern Gas Turbine Fuel Injectors

2014 ◽  
Author(s):  
A. G. Barker ◽  
J. F. Carrotte
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Liquid Fuel ◽  
Swirling Flow ◽  
Subsequent Development ◽  
Potential Effect ◽  
Far Field ◽  
Fuel Injector ◽  
Swirl Vane ◽  
The Impact

In modern gas turbine engines swirl is typically imparted to the airflow as it enters the region of heat release to stabilize the flame. This swirling airstream is often highly turbulent and contains non-uniformities such as swirl vane wakes. However, it is within this environment that fuel atomization takes place. This paper is concerned with the potential effect of these airstream characteristics on the atomization process. Such a flow field is difficult to capture within simplified geometries and so measurements have been made within, and downstream of, injector representative geometries. This is experimentally challenging and required the application of a variety of techniques. The geometry considered is thought typical of an air-blast style injector, as may be used within current or future applications, whereby liquid fuel is introduced onto a pre-filming surface over which an airstream passes. Data is presented which characterizes the atomizing airstream presented to the pre-filming region. This includes significant flow field non-uniformities and turbulence characteristics that are mainly associated with the swirling flow along with the vanes used to impart this swirl. The subsequent development of these aerodynamic features over the pre-filming surface is also captured with, for example, swirl vane wakes being evident through the injector passage and into the downstream flow field. It is argued these characteristics will be common to many injector designs. Measurements with and without fuel indicate the effect of the liquid film, on the non-dimensional aerodynamic flow field upstream of the pre-filming region, is minimal. However, the amount of airflow passing through the pre-filming passage is affected. In addition to characterization of the airstream, its impact on the liquid fuel film and its development along the pre-filming surface is visualized. Furthermore, PDA measurements downstream of the fuel injector (i.e. the injector ‘far-field) are presented and the observed spray characteristics spatially correlated with the upstream aerodynamic atomizing flow field. Hence for the first time a series of experimental techniques have been used to capture and correlate both near and far field atomization characteristics within an engine representative aerodynamic flow field.

The Use of Perforated Damping Liners in Aero Gas Turbine Combustion Systems

2011 ◽  
Author(s):  
Jochen Rupp ◽  
Jon Carrotte ◽  
Michael Macquisten
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Gas Turbine ◽  
Analytical Model ◽  
Operating Conditions ◽  
Acoustic Energy ◽  
Fuel Injector ◽  
Flame Tube ◽  
Gas Turbine Combustion ◽  
Combustion Systems

This paper considers the use of perforated porous liners for the absorption of acoustic energy within aero style gas turbine combustion systems. The overall combustion system pressure drop means that the porous liner (or ‘damping skin’) is typically combined with a metering skin. This enables most of the mean pressure drop, across the flame tube, to occur across the metering skin with the porous liner being exposed to a much smaller pressure drop. In this way porous liners can potentially be designed to provide significant levels of acoustic damping, but other requirements (e.g. cooling, available space envelope etc) must also be considered as part of this design process. A passive damper assembly was incorporated within an experimental isothermal facility that simulated an aero-engine style flame tube geometry. The damper was therefore exposed to the complex flow field present within an engine environment (e.g. swirling efflux from a fuel injector, coolant film passing across the damper surface etc.). In addition, plane acoustic waves were generated using loudspeakers so that the flow field was subjected to unsteady pressure fluctuations. This enabled the performance of the damper, in terms of its ability to absorb acoustic energy, to be evaluated. To complement the experimental investigation a simplified 1D analytical model was also developed and validated against the experimental results. In this way not only was the performance of the acoustic damper evaluated, but also the fundamental processes responsible for this measured performance could be identified. Furthermore the validated analytical model also enabled a wide range of damping geometry to be assessed for a range of operating conditions. In this way damper geometry can be optimized (e.g. for a given space envelope) whilst the onset of non-linear absorption (and hence the potential to ingest hot gas) can also be identified.

Gas Turbine Combustor Rig Development and Initial Observations at Cold and Reacting Flow Conditions

2016 ◽  
Author(s):  
David Gomez-Ramirez ◽  
Sandeep Kedukodi ◽  
Siddhartha Gadiraju ◽  
Srinath V. Ekkad ◽  
Hee-Koo Moon ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Gas Turbine ◽  
Primary Objective ◽  
Reacting Flow ◽  
Fuel Injector ◽  
Imaging Data ◽  
Test Rig ◽  
Gas Turbine Combustor ◽  
Inlet Conditions

The present paper describes the first phase of the design and development of a realistic, high-pressure, full-scale research gas turbine combustor at Virginia Tech. The final test rig will be capable of operating at inlet temperatures of 650 K, pressures up to 9.28 Bar (120 psig), maximum air inlet flow rates of 1.27 kg/s (2.8 lbm/s), and allow for variations in the geometry of the combustor model. The first phase consists of a low-pressure (atmospheric) optical combustor for heat transfer and flow-field measurements at isothermal and reacting conditions. The combustor model is equipped with an industrial low emission fuel injector from Solar Turbines Incorporated, used in their land based gas turbine Taurus-60. The primary objective of the developed rig is to provide additional insight into the heat transfer processes that occur within gas turbine combustors, primarily the convective component, which has not been characterized. A future phase of the test rig development will incorporate a pressure vessel that will allow for the operation of the combustor simulator at higher pressures. In the present publication, the design methodology and considerations, as well as the challenges encountered during the design of the first phase of the simulator are briefly discussed. An overview is given on the design of the instrumentation and process piping surrounding the test rig, including ASME codes followed as well as the instrumentation and equipment selected. A detailed description of the test section design is given, highlighting the design for high temperature operation. As an example of the capabilities of the rig, representative measurements are presented. Characterization of the isothermal flow field using planar Particle Image Velocimetry (PIV) at a Reynolds number of 50 000 was performed and compared with flame imaging data at the same inlet conditions operating at an equivalence ratio of 0.7. The data suggests that the flame location follows the maximum turbulent kinetic energy as measured in the isothermal field. Representative data from the computational efforts are also presented and compared with the experimental measurements. Future work will expand on both reacting and isothermal PIV and heat transfer measurements, as well as computational validations.

Experimental and Numerical Spray Characterization of a Gas Turbine Fuel Atomizer in Cross Flow

2002 ◽  
Author(s):  
F. A. Tap ◽  
A. J. Dean ◽  
J. P. Van Buijtenen
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Droplet Size ◽  
Cross Flow ◽  
Field Measurements ◽  
Fuel Injector ◽  
Ambient Conditions ◽  
Air Stream ◽  
Break Up

An experimental and numerical characterization of a macrolaminate pressure atomizer, placed perpendicularly to a high-velocity, turbulent air stream, is presented in this work. The purpose of the study was to compare detailed spray measurements with computations using a commercial CFD code. This study was part of the development of the premixing section of a midsize gas turbine, redesigned to meet low emissions and dual fuel market requirements. First, the spray characteristics were determined by injecting into a quiescent environment at ambient conditions. This data provided input for CFD calculations. Then the fuel injector was placed in a test section, at ambient conditions as well, that simulated the cross flow position of the atomizer in the prototype combustor. Droplet size and velocity were measured downstream of the injector nozzle, using a one-dimensional Phase Doppler Particle Analyzer. Measurements were done in two measuring planes. Flow field measurements were made to establish a common base for the computations. 2D computations were made of these experiments, using a k-ε turbulence model. The droplet trajectories were calculated with a Lagrangian ‘random walk’ technique, including drop break-up. The computed droplet size and velocity show agreement with the measurements. Drop break-up was also well represented by the model. The computed dispersion of the injected mass is not in agreement with the measured profile. This discrepancy in droplet dispersion is possibly due to high turbulence levels in the flow field, which were not well captured in the model.

The Use of Perforated Damping Liners in Aero Gas Turbine Combustion Systems

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Jochen Rupp ◽  
Jon Carrotte ◽  
Michael Macquisten
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Gas Turbine ◽  
Analytical Model ◽  
Operating Conditions ◽  
Acoustic Energy ◽  
Fuel Injector ◽  
Flame Tube ◽  
Gas Turbine Combustion ◽  
Combustion Systems

This paper considers the use of perforated porous liners for the absorption of acoustic energy within aero style gas turbine combustion systems. The overall combustion system pressure drop means that the porous liner (or “damping skin”) is typically combined with a metering skin. This enables most of the mean pressure drop, across the flame tube, to occur across the metering skin with the porous liner being exposed to a much smaller pressure drop. In this way porous liners can potentially be designed to provide significant levels of acoustic damping, but other requirements (e.g., cooling, available space envelope, etc) must also be considered as part of this design process. A passive damper assembly was incorporated within an experimental isothermal facility that simulated an aero-engine style flame tube geometry. The damper was therefore exposed to the complex flow field present within an engine environment (e.g., swirling efflux from a fuel injector, coolant film passing across the damper surface, etc.). In addition, plane acoustic waves were generated using loudspeakers so that the flow field was subjected to unsteady pressure fluctuations. This enabled the performance of the damper, in terms of its ability to absorb acoustic energy, to be evaluated. To complement the experimental investigation a simplified one-dimensional (1D) analytical model was also developed and validated against the experimental results. In this way not only was the performance of the acoustic damper evaluated, but also the fundamental processes responsible for this measured performance could be identified. Furthermore, the validated analytical model also enabled a wide range of damping geometry to be assessed for a range of operating conditions. In this way damper geometry can be optimized (e.g., for a given space envelope) while the onset of nonlinear absorption (and hence the potential to ingest hot gas) can also be identified.

The Civic: A Concept in Vortex Induced Combustion for the Solar Gemini 10 kW Gas Turbine

1981 ◽  
Vol 103 (1) ◽  
pp. 34-42 ◽  
Author(s):  
J. R. Shekleton
Keyword(s):  
Gas Turbine ◽  
Diffusion Flames ◽  
Reynolds Numbers ◽  
Flame Stabilization ◽  
Fuel Injector ◽  
Combustion Chambers ◽  
Turbine Generator ◽  
Fuel Injectors ◽  
Swirl Flame ◽  
Combustion Processes

The Radial Engine Division of Solar Turbines International, an Operating Group of International Harvester, under contract to the U.S. Army Mobility Equipment Research & Development Command, developed and qualified a 10 kW gas turbine generator set. The very small size of the gas turbine created problems and, in the combustor, novel solutions were necessary. Differing types of fuel injectors, combustion chambers, and flame stabilizing methods were investigated. The arrangement chosen had a rotating cup fuel injector, in a can combustor, with conventional swirl flame stabilization but was devoid of the usual jet stirred recirculation. The use of centrifugal force to control combustion conferred substantial benefit (Rayleigh Instability Criteria). Three types of combustion processes were identified: stratified and unstratified charge (diffusion flames) and pre-mix. Emphasis is placed on five nondimensional groups (Richardson, Bagnold, Damko¨hler, Mach, and Reynolds numbers) for the better control of these combustion processes.

Finite Element Volume Analysis of Propane Preheated Air Flame Passing Through a Minichannel

2014 ◽  
Author(s):  
Masoud Darbandi ◽  
Majid Ghafourizadeh ◽  
Gerry E. Schneider
Keyword(s):  
Finite Element ◽  
Radiation Effects ◽  
Mixture Fraction ◽  
Flame Structure ◽  
Current Method ◽  
Reacting Flow ◽  
Wall Functions ◽  
Flamelet Model ◽  
Combustion Modeling ◽  
Detailed Kinetics

A hybrid finite-element-volume FEV method is extended to simulate turbulent non-premixed propane air preheated flame in a minichannel. We use a detailed kinetics scheme, i.e. GRI mechanism 3.0, and the flamelet model to perform the combustion modeling. The turbulence-chemistry interaction is taken into account in this flamelet modeling using presumed shape probability density functions PDFs. Considering an upwind-biased physics for the current reacting flow, we implement the physical influence upwinding scheme PIS to estimate the cell-face mixture fraction variance in this study. To close the turbulence closure, we employ the two-equation standard κ-ε turbulence model incorporated with suitable wall functions. Supposing an optically thin limit, it needs to take into account radiation effects of the most important radiating species in the current modeling. Despite facing with so many flame instabilities in such small size configuration, the current method performs suitably with proper convergence, and the encountered instabilities are damped out automatically. Comparing with the experimental measurements, the current extended method accurately predicts the flame structure in the minichannel configuration.

The Use of the InfraAlyzer 260 Whole Grain for Water and Fat Determination in Pork Meat

1998 ◽  
Vol 6 (A) ◽  
pp. A83-A86 ◽  
Author(s):  
Henryk W. Czarnik-Matusewicz ◽  
Adolf Korniewicz
Keyword(s):  
Independent Set ◽  
Cost Effective ◽  
Standard Errors ◽  
Longissimus Dorsi ◽  
Pork Meat ◽  
Meat Processing ◽  
Whole Grain ◽  
Accurate Analysis ◽  
Meat Composition ◽  
Effective Manner

This study describes an investigation into the utility of the filter near infarared (NIR) instrument – InfraAlyzer 260 Whole Grain (Bran+Luebbe GmbH) for the routine analysis of pork meat composition in a rapid and cost-effective manner. Water and fat were the proximate constituents selected for investigation on the grounds of their importance in pork meat processing and marketing. Fresh slices of Longissimus dorsi (LD) muscle weighing approximately 300 g were taken from carcasses. The LD samples were then cut and homogenized with a rotating knife homogenizer prior to NIR and chemical analysis according to the ISO-procedures. The selected samples ( n = 79) were scanned in an open sample cup using all 19 filters of an InfraAlyzer 260 Whole Grain with wavelenghts between 1110 and 2310 nm. The process of calibration (MLR method) was performed by using SESAME ver. 2.10 software (Bran+Luebbe GmbH) on an interfaced PC computer. Standard errors of calibration were 0.16 % for water and 0.17 % for fat. Calibrations were validated with an independent set of 21 samples of the same types. Standard errors of validation were 0.17 % and 0.20 % for water and fat, respectively. The obtained results show that InfraAlyzer 260 Whole Grain can be used for the rapid and accurate analysis of components of the pork meat.

Modeling of Gas Turbine Fuel Nozzle Spray

1997 ◽  
Vol 119 (1) ◽  
pp. 34-44 ◽  
Author(s):  
N. K. Rizk ◽  
J. S. Chin ◽  
M. K. Razdan
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
Near Field ◽  
Continuous Phase ◽  
Liquid Sheet ◽  
Vapor Concentration ◽  
Fuel Vapor ◽  
Fuel Injector ◽  
Gas Temperature ◽  
Sheet Breakup

Satisfactory performance of the gas turbine combustor relies on the careful design of various components, particularly the fuel injector. It is, therefore, essential to establish a fundamental basis for fuel injection modeling that involves various atomization processes. A two-dimensional fuel injection model has been formulated to simulate the airflow within and downstream of the atomizer and address the formation and breakup of the liquid sheet formed at the atomizer exit. The sheet breakup under the effects of airblast, fuel pressure, or the combined atomization mode of the airassist type is considered in the calculation. The model accounts for secondary breakup of drops and the stochastic Lagrangian treatment of spray. The calculation of spray evaporation addresses both droplet heat-up and steady-state mechanisms, and fuel vapor concentration is based on the partial pressure concept. An enhanced evaporation model has been developed that accounts for multicomponent, finite mass diffusivity and conductivity effects, and addresses near-critical evaporation. The presents investigation involved predictions of flow and spray characteristics of two distinctively different fuel atomizers under both nonreacting and reacting conditions. The predictions of the continuous phase velocity components and the spray mean drop sizes agree well with the detailed measurements obtained for the two atomizers, which indicates the model accounts for key aspects of atomization. The model also provides insight into ligament formation and breakup at the atomizer exit and the initial drop sizes formed in the atomizer near field region where measurements are difficult to obtain. The calculations of the reacting spray show the fuel-rich region occupied most of the spray volume with two-peak radial gas temperature profiles. The results also provided local concentrations of unburned hydrocarbon (UHC) and carbon monoxide (CO) in atomizer flowfield, information that could support the effort to reduce emission levels of gas turbine combustors.

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