Design of a Non-Reactive Warm Rig With Real Lean-Premix Combustor Swirlers and Film-Cooled First Stage Nozzles

2020 ◽  
Author(s):  
Simone Cubeda ◽  
Tommaso Bacci ◽  
Lorenzo Mazzei ◽  
Simone Salvadori ◽  
Bruno Facchini ◽  
...  
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Heavy Duty ◽  
Design Practices ◽  
Standard Design ◽  
Real Hardware ◽  
Heavy Duty Gas Turbine

Abstract Modern industrial gas turbines typically employ lean-premix combustors, which can limit pollutant emissions thanks to premixed flames, while sustaining high turbine inlet temperatures that increase the single-cycle thermal efficiency. As such, gas-turbine first stage nozzles can be characterized by a highly-swirled and temperature-distorted inlet flow field. However, due to several sources of uncertainty during the design phase, wide safety margins are commonly adopted, having a direct impact on engine performance and efficiency. Therefore, aiming at increasing the knowledge on combustor-turbine interaction and improving standard design practices, a non-reactive test rig composed of real hardware was assembled at the University of Florence, Italy. The rig, accommodating three lean-premix swirlers within a combustion chamber and two first stage film-cooled nozzles of a Baker Hughes heavy-duty gas turbine, is operated in similitude conditions. The rig has been designed to reproduce the real engine periodic flow field on the central vane channel, also allowing for measurements far enough from the lateral walls. The periodicity condition on the central sector was achieved by the proper design of both the angular profile and pitch value of the tailboards with respect to the vanes, which was carried out in a preliminary phase via a Design of Experiments procedure. In addition, circular ducts needed to be installed at the injectors outlet section to preserve the non-reactive swirling flow down to the nozzles’ inlet plane. The combustor-turbine interface section has been experimentally characterized in nominal operating conditions as per the temperature, velocity and pressure fields by means of a five-hole pressure probe provided with a thermocouple, installed on an automatic traverse system. To study the evolution of the combustor outlet flow through the vanes and its interaction with the film-cooling flow, such measurements have been replicated also downstream of the vanes’ trailing edge. This work allowed for designing and providing preliminary data on a combustor simulator capable of equipping and testing real hardware film-cooled nozzles of a heavy-duty gas turbine. Ultimately, the activity sets the basis for an extensive test campaign aimed at characterizing the metal temperature, film effectiveness and heat transfer coefficient at realistic aerothermal conditions. In addition, and by leveraging experimental data, this activity paves the way for a detailed validation of current design practices as well as more advanced numerical methodologies such as Scale-Adaptive Simulations of the integrated combustor-turbine domain.

Numerical Investigations of Pollutant Emissions From Novel Heavy-Duty Gas Turbine Burners Operated With Natural Gas

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Daniele Pampaloni ◽  
Pier Carlo Nassini ◽  
Antonio Andreini ◽  
Bruno Facchini ◽  
Matteo Cerutti
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Design Process ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Formation Mechanisms ◽  
Heavy Duty ◽  
Heavy Duty Gas Turbine ◽  
Cost Efficient

Abstract A numerical investigation of pollutant emissions of a novel dry low-emissions burner for heavy-duty gas turbine applications is presented. The objective of this work is to develop and assess a robust and cost-efficient numerical setup for the prediction of NOx and CO emissions in industrial gas turbines and to investigate the pollutant formation mechanisms, thus supporting the design process of a novel low-emission burner. To this end, a comparison against experimental data, from a recent experimental campaign performed by BHGE in cooperation with University of Florence, has been exploited. In the first part of this work, a Reynolds-averaged Navier–Stokes (RANS) approach on both a simplified geometry and the complete domain is adopted to characterize the global flame behavior and validate the numerical setup. Then, unsteady simulations exploiting the scale adaptive simulation (SAS) approach have been performed to assess the prediction improvements that can be obtained with the unsteady modeling of the flame. For all simulations, the flamelet generated manifold (FGM) model has been used, allowing the reliable and cost-efficient application of detailed chemistry mechanisms in computational fluid dynamics (CFD) simulation. However, FGM typically faces issues predicting flame emissions, such as NOx and CO, due to the wide range of time scales involved, from turbulent mixing to pollutant species oxidation. Specific models are typically used to predict NOx emissions, starting from the converged flow-field and introducing additional transport equations. Also CO prediction, especially at part-load operating conditions could be an issue for flamelet-based model: in fact, as the load decreases and the extinction limit approaches, a superequilibrium CO concentration, which cannot be accurately predicted by FGM, appears in the exhaust gases. To overcome this issue, a specific CO-burn-out model, following the original idea proposed by Klarmann, has been implemented in ANSYS fluent. The model allows to decouple the effective CO oxidation term from the one computed by FGM, defining a postflame zone where the source term of CO is treated following the Arrhenius formulation. In order to support the design process, an indepth CFD investigation has been carried out, evaluating the impact of an alternative burner geometrical configuration on stability and emissions and providing detailed information about the main regions and mechanisms of pollutants production. The outcomes support the analysis of experimental results, allowing an indepth investigation of the complex flow-field and the flame-related quantities, which have not been measured during the tests.

Numerical Investigations of Pollutant Emissions From Novel Heavy Duty Gas Turbine Burners Operated With Natural Gas

2019 ◽  
Author(s):  
Daniele Pampaloni ◽  
Pier Carlo Nassini ◽  
Antonio Andreini ◽  
Bruno Facchini ◽  
Matteo Cerutti
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Design Process ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Formation Mechanisms ◽  
Heavy Duty ◽  
Heavy Duty Gas Turbine ◽  
Cost Efficient

Abstract A numerical investigation of pollutant emissions of a novel dry low-emissions burner for heavy-duty gas turbine applications is presented. The objective of the work is to develop and assess a robust and cost-efficient numerical setup for the prediction of NOx and CO emissions in industrial gas turbines and to investigate the pollutant formation mechanisms, thus supporting the design process of a novel low-emission burner. To this end, a comparison against experimental data, from a recent experimental campaign performed by BHGE in cooperation with University of Florence, has been exploited. In the first part of this work, a RANS approach on both a simplified geometry and the complete domain is adopted to characterize the global flame behavior and validate the numerical setup. Then, unsteady simulations exploiting the Scale Adaptive Simulation (SAS) approach have been performed to assess the prediction improvements that can be obtained with the unsteady modelling of the flame. For all simulations, the Flamelet Generated Manifold (FGM) model has been used, allowing the reliable and cost-efficient application of detailed chemistry mechanisms in CFD simulation. However, FGM typically faces issues predicting flame emissions, such as NOx and CO, due to the wide range of time scales involved, from turbulent mixing to pollutant species oxidation. Specific models are typically used to predict NOx emissions, starting from the converged flow field and introducing additional transport equations. Also CO prediction, especially at part-load operating conditions could be an issue for flamelet-based model: in fact, as the load decreases and the extinction limit approaches, a super-equilibrium CO concentration, which cannot be accurately predicted by FGM, appears in the exhaust gases. To overcome this issue, a specific CO burn-out model, following the original idea proposed by Klarmann, has been implemented in ANSYS Fluent. The model allows to decouple the effective CO oxidation term from the one computed by FGM, defining a post-flame zone where the source term of CO is treated following the Arrhenius formulation. In order to support the design process, an in-depth CFD investigation has been carried out, evaluating the impact of an alternative burner geometrical configuration on stability and emissions and providing detailed information about the main regions and mechanisms of pollutants production. The outcomes support the analysis of experimental results, allowing an in-depth investigation of the complex flow-field and the flame-related quantities, which have not been measured during the tests.

Experience With Large Heavy-Duty Gas Turbine Rotors

1981 ◽  
Author(s):  
O. R. Schmoch ◽  
B. Deblon
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Strength Properties ◽  
Operating Conditions ◽  
Material Strength ◽  
Heavy Duty ◽  
Turbine Rotors ◽  
Heavy Duty Gas Turbine ◽  
Response To Temperature

The peripheral speeds of the rotors of large heavy-duty gas turbines have reached levels which place extremely high demands on material strength properties. The particular requirements of gas turbine rotors, as a result of the cycle, operating conditions and the ensuing overall concepts, have led different gas turbine manufacturers to produce special structural designs to resolve these problems. In this connection, a report is given here on a gas turbine rotor consisting of separate discs which are held together by a center bolt and mutually centered by radial serrations in a manner permitting expansion and contraction in response to temperature changges. In particular, the experience gained in the manufacture, operation and servicing are discussed.

Three-Dimensional Time-Resolved Flow Field in the First and Last Turbine Stage of a Heavy Duty Gas Turbine: Part II — Interpretation of Blade Pressure Fluctuations

2000 ◽  
Author(s):  
Martin von Hoyningen-Huene ◽  
Wolfram Frank ◽  
Alexander R. Jung
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Potential Interaction ◽  
Heavy Duty ◽  
Turbine Stage ◽  
Count Ratio ◽  
Heavy Duty Gas Turbine

Unsteady stator-rotor interaction in gas turbines has been investigated experimentally and numerically for some years now. Most investigations determine the pressure fluctuations in the flow field as well as on the blades. So far, little attention has been paid to a detailed analysis of the blade pressure fluctuations. For further progress in turbine design, however, it is mandatory to better understand the underlying mechanisms. Therefore, computed space–time maps of static pressure are presented on both the stator vanes and the rotor blades for two test cases, viz the first and the last turbine stage of a modern heavy duty gas turbine. These pressure fluctuation charts are used to explain the interaction of potential interaction, wake-blade interaction, deterministic pressure fluctuations, and acoustic waveswith the instantaneous surface pressure on vanes and blades. Part I of this two-part paper refers to the same computations, focusing on the unsteady secondary now field in these stages. The investigations have been performed with the flow solver ITSM3D which allows for efficient simulations that simulate the real blade count ratio. Accounting for the true blade count ratio is essential to obtain the correct frequencies and amplitudes of the fluctuations.

Three-Dimensional Time-Resolved Flow Field in the First and Last Turbine Stage of a Heavy Duty Gas Turbine: Part I — Secondary Flow Field

2000 ◽  
Author(s):  
Martin von Hoyningen-Huene ◽  
Wolfram Frank ◽  
Alexander R. Jung
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Companion Paper ◽  
Heavy Duty ◽  
Turbine Stage ◽  
Time Resolved ◽  
Heavy Duty Gas Turbine ◽  
Secondary Flow Field

Unsteady stator-rotor interaction in gas turbines has been investigated both experimentally and numerically for some years now. Even though the numerical methods are still in development, today they have reached a certain degree of maturity allowing industry to focus on the results of the computations and their impact on turbine design, rather than on a further improvement of the methods themselves. The key to increase efficiency in modern gas turbines is a better understanding and subsequent optimization of the loss-generation mechanisms. A major part of these are the secondary losses. To this end, this paper presents the time-resolved secondary flow field for the two test cases computed, viz the first and the last turbine stage of a modern heavy duty gas turbine. A companion paper referring to the same computations focuses on the unsteady pressure fluctuations on vanes and blades. The investigations have been performed with the flow solver ITSM3D which allows for efficient calculations that simulate the real blade count ratio. This is a prerequisite to simulate the unsteady phenomena in frequency and amplitude properly.

Trapped Vortex Combustor Performance for Heavy-Duty Gas Turbines

2008 ◽  
Author(s):  
Joel M. Haynes ◽  
Daniel Micka ◽  
Ben Hojnacki ◽  
Craig Russell ◽  
John Lipinski ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Nox Reduction ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Reactor Model ◽  
Emission Performance ◽  
Lean Premixed ◽  
Heavy Duty Gas Turbine ◽  
Trapped Vortex

The application of the trapped vortex combustor (TVC) concept to heavy-duty gas turbine conditions has been explored. Combustor stability, lean blow out, and emission performance requirements limit design options for conventional lean premixed combustors. The TVC concept has demonstrated reduced emissions and high turndown with liquid fuels and could overcome existing lean premixed performance constraints as well. The present study examines premixed injection of natural gas into the TVC at heavy-duty gas turbine conditions. The emission performance is measured over a range of operating conditions. The combustor turndown and dynamics performance are also presented. To forecast the performance potential of the TVC combustor a chemical reactor network model was developed. The model was anchored with experimental data and implemented in the prediction of TVC combustor emissions and turndown performance. The reactor model confirms that NOx reduction greater than 60% is possible using a trapped vortex combustor (TVC).

scholarly journals A Different Approach to Gas Turbine Exhaust Silencing

1974 ◽  
Author(s):  
Marv Weiss
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Unique Method ◽  
Acoustic Testing ◽  
Gas Turbine Exhaust ◽  
Attenuation Values ◽  
Turbine Exhaust

A unique method for silencing heavy-duty gas turbines is described. The Switchback exhaust silencer which utilizes no conventional parallel baffles has at operating conditions measured attenuation values from 20 dB at 63 Hz to 45 dB at higher frequencies. Acoustic testing and analyses at both ambient and operating conditions are discussed.

Protective Systems for Gas Turbines in Industry

1974 ◽  
Author(s):  
J. N. Shinn
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Comprehensive System ◽  
Heavy Duty ◽  
Protective System ◽  
System Philosophy ◽  
Heavy Duty Gas Turbine ◽  
Protective Systems

Modern heavy-duty gas turbine installations employ a comprehensive system of protective circuits to provide needed equipment protection without jeopardizing plant reliability. The design of these circuits and the overall protective system philosophy are discussed to illustrate how protection and reliability are maximized. Experience gained to date on the application of these protective circuits also is reviewed.

scholarly journals Maintenance of Industrial Gas Turbines

1975 ◽  
Author(s):  
R. H. Knorr ◽  
G. Jarvis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heavy Duty ◽  
Factors Affecting ◽  
Maintenance Program ◽  
Industrial Gas Turbines ◽  
Heavy Duty Gas Turbine ◽  
Maintenance Requirements

This paper describes the maintenance requirements of the heavy-duty gas turbine. The various inspections and factors affecting maintenance are defined, and basic guidelines are presented for a planned maintenance program.

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