The Use of Electrostatic Charge Measurements as an Early Warning of Distress in Heavy-Duty Gas Turbines

2001 ◽  
Author(s):  
G. L. Lapini ◽  
M. Zippo ◽  
G. Tirone
Keyword(s):  
Monitoring System ◽  
Early Warning ◽  
Gas Turbines ◽  
Electrostatic Charge ◽  
Electric Utility ◽  
Operating Conditions ◽  
System Response ◽  
Jet Engines ◽  
Heavy Duty ◽  
Demonstration Program

The idea of measuring the electrostatic charge associated with the debris contained in the exhaust gases of a gas turbine (sometimes named EDMS, Engine Debris Monitoring System, or EEMS, Electrostatic Engine Monitoring System) has been demonstrated by several authors as an interesting diagnostic tool for the early warning of possible internal distresses (rubs, coating wear, hot spots in combustors, improper combustion, etc.) especially for jet engines or aeroderivative gas turbines. While potentially applicable to machines of larger size, the possibility of transferring this monitoring technology to heavy-duty gas turbines, which have exhaust ducts much bigger in size and different operating conditions, should be demonstrated. The authors present a synthesis of their experience and of the most significant data collected during a demonstration program performed on behalf of ENEL, the main Italian electric utility. The purpose of this program was to test this concept in real operating conditions on large turbines, and hence to evaluate the influence of the operating conditions on the system response and to assess its sensitivity to possible distresses. A good amount of testing has been performed, during this program, both on a full scale combustion rig, and on two machines rated at about 120 MW, during their normal and purposely perturbed operating conditions in a power plant. The authors, on the basis of the encouraging results obtained to date, comment on the work still required to bring this technology to full maturity.

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.

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.

scholarly journals A SVDD and K-Means Based Early Warning Method for Dual-Rotor Equipment under Time-Varying Operating Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhinong Jiang ◽  
Minghui Hu ◽  
Kun Feng ◽  
Hao Wang
Keyword(s):  
Test Data ◽  
Early Warning ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Cluster Center ◽  
Time Varying ◽  
Fixed Threshold ◽  
Alarm Threshold ◽  
Rotor Equipment

Under frequently time-varying operating conditions, equipment with dual rotors like gas turbines is influenced by two rotors with different rotating speeds. Alarm methods of fixed threshold are unable to consider the influences of time-varying operating conditions. Hence, those methods are not suitable for monitoring dual-rotor equipment. An early warning method for dual-rotor equipment under time-varying operating conditions is proposed in this paper. The influences of time-varying rotating speeds of dual rotors on alarm thresholds have been considered. Firstly, the operating conditions are divided into several limited intervals according to rotating speeds of dual rotors. Secondly, the train data within each interval is processed by SVDD and the allowable ranges (i.e., the alarm threshold) of the vibration are determined. The alarm threshold of each interval of operating conditions is obtained. The alarm threshold can be expressed as a sphere, whose controlling parameters are the coordinate of the center and the radius. Then, the cluster center of the test data, whose alarm state is to be judged, can be extracted through K-means. Finally, the alarm state can be obtained by comparing the cluster center with the corresponding sphere. Experiments are conducted to validate the proposed method.

Numerical and Experimental Investigation of Secondary Flows and Influence of Air System Design on Heavy-Duty Gas Turbine Performance

2012 ◽  
Author(s):  
Luca Bozzi ◽  
Enrico D’angelo
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Combined Cycle ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Turbine Performance ◽  
Air System ◽  
Secondary Air

High turn-down operating of heavy-duty gas turbines in modern Combined Cycle Plants requires a highly efficient secondary air system to ensure the proper supply of cooling and sealing air. Thus, accurate performance prediction of secondary flows in the complete range of operating conditions is crucial. The paper gives an overview of the secondary air system of Ansaldo F-class AEx4.3A gas turbines. Focus of the work is a procedure to calculate the cooling flows, which allows investigating both the interaction between cooled rows and additional secondary flows (sealing and leakage air) and the influence on gas turbine performance. The procedure is based on a fluid-network solver modelling the engine secondary air system. Parametric curves implemented into the network model give the consumption of cooling air of blades and vanes. Performances of blade cooling systems based on different cooling technology are presented. Variations of secondary air flows in function of load and/or ambient conditions are discussed and justified. The effect of secondary air reduction is investigated in details showing the relationship between the position, along the gas path, of the upgrade and the increasing of engine performance. In particular, a section of the paper describes the application of a consistent and straightforward technique, based on an exergy analysis, to estimate the effect of major modifications to the air system on overall engine performance. A set of models for the different factors of cooling loss is presented and sample calculations are used to illustrate the splitting and magnitude of losses. Field data, referred to AE64.3A gas turbine, are used to calibrate the correlation method and to enhance the structure of the lumped-parameters network models.

Improvement of Conventional Seals for Stator-Rotor Cavities of Heavy-Duty Gas Turbines by Application of Interstage Brush-Seals

2013 ◽  
Author(s):  
Marco Mantero ◽  
Alessandro Vinci ◽  
Luca Bozzi ◽  
Enrico D’Angelo
Keyword(s):  
Gas Turbines ◽  
Operating Conditions ◽  
Design Flow ◽  
Heavy Duty ◽  
Labyrinth Seals ◽  
Flow Process ◽  
Brush Seal ◽  
Temperature And Pressure ◽  
Brush Seals ◽  
Secondary Air

In order to achieve significant secondary air savings in heavy duty gas turbines, a remarkable item of improvement is the reduction of seal flows for turbine stator-rotor cavities. The optimization of such flows allows to avoid waste of air, obligatory with standard labyrinth seals, to ensure the minimum sealing flow rate in all operating conditions. Based on the experience gained in the design of sealing system of stator-rotor cavities with standard seals, the project of installation of inter-stage brush-seals was undertaken incorporating such devices into the vane seal rings of 2nd and 3rd turbine stages of a AE94.3A Gas Turbine (GT). The paper offers a detailed description of the installation project. The following describes in detail the design flow process and the calculation methodologies used, step by step, to define the geometry of brush-seals in order to ensure mechanical integrity and durability, needed in the commercial operation, without thereby affecting the performance. The first prototype of brush-seal devices has been installed on a AE94.3A4 unit of the Ansaldo fleet. In order to verify the behavior of stator-rotor sealing system, in particular in terms of temperature and pressure variations, vane seal rings have been equipped with special instrumentation. A series of tests to optimize the set points of bleed control valves was carried out.

Developments and Experiences With Pulsation Measurements for Heavy-Duty Gas Turbines

2007 ◽  
Author(s):  
Hanspeter Zinn ◽  
Michael Habermann
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Optimal Operation ◽  
Operating Conditions ◽  
Probe Design ◽  
Heavy Duty ◽  
Engine Operation ◽  
Accuracy Measurement ◽  
Operation Conditions

The dynamical combustion processes (pulsations) of heavy-duty gas turbines must be supervised by suitable instrumentation for optimal operation of the engine regarding emissions and component life. But the hostile environment of the combustor makes it difficult to perform the measurements. There are two possible approaches to measure the combustor pulsations. Either a high temperature sensor is placed as close as possible to the combustion chamber to measure the acoustics directly (Cavity Type Probe), or the acoustic signal is led to the outside of the engine by means of a reflection free waveguide, where a dynamic pressure sensor picks up the passing signal (Long Line Probe). Both approaches were developed and investigated in detail. This paper describes the past and current efforts in refining the probe designs for use in the harsh operational environment while maintaining sensor accuracy, measurement range and lifetime as a rugged probe. Theoretical and laboratory investigations were undertaken to increase the useable frequency range of the Cavity Type Probe up to 8kHz under engine operation conditions. This was made possible with a smaller high temperature transducer, which is the result of a cooperative development project with a sensor manufacturer. Experiences with both probe concepts on Alstom’s GT26 Test Power Plant in Birr and on field engines provided clear confirmation that the Cavity Type Probe design with an advanced sensor now fulfils all initially defined requirements of acoustic combustion measurements on heavy-duty gas turbines. On the contrary, the waveguide design principle has fundamental limitations in the direct measurement of the combustion acoustics at gas turbine operating conditions.

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.

An Efficient Procedure for the Analysis of Heavy Duty Gas Turbine Secondary Flows in Different Operating Conditions

2010 ◽  
Author(s):  
Matteo Cerutti ◽  
Luca Bozzi ◽  
Federico Bonzani ◽  
Carlo Carcasci
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Efficient Procedure ◽  
Air System ◽  
Secondary Air ◽  
Flow Functions

Combined cycle and partial load operating of modern heavy-duty gas turbines require highly efficient secondary air systems to supply both cooling and sealing air. Accurate performance predictions are then a fundamental demand over a wide range of operability. The paper describes the development of an efficient procedure for the investigation of gas turbine secondary flows, based on an in-house made fluid network solver, written in Matlab® environment. Fast network generation and debugging are achieved thanks to Simulink® graphical interface and modular structure, allowing predictions of the whole secondary air system. A crucial aspect of such an analysis is the calculation of blade and vane cooling flows, taking into account the interaction between inner and outer extraction lines. The problem is closed thanks to ad-hoc calculated transfer functions: cooling system performances and flow functions are solved in a pre-processing phase and results correlated to influencing parameters using Response Surface Methodology (RSM) and Design of Experiments (DOE) techniques. The procedure has been proved on the secondary air system of the AE94.3A2 Ansaldo Energia gas turbine. Flow functions for the cooling system of the first stage blade, calculated by RSM and DOE techniques, are presented. Flow functions based calculation of film cooling, tip cooling and trailing edge cooling air flows is described in details.

Remote Monitoring and Diagnostics System for GE Heavy Duty Gas Turbines

2000 ◽  
Author(s):  
Dincer Ozgur ◽  
Arkalgud N. Lakshminarasimha ◽  
Richard Rucigay ◽  
Mahesh Morjaria ◽  
S. Sanborn
Keyword(s):  
Remote Monitoring ◽  
Gas Turbines ◽  
Power Plants ◽  
Operating Conditions ◽  
Success Factor ◽  
Heavy Duty ◽  
Potential Problems ◽  
Power Generation Equipment ◽  
Heavy Duty Gas Turbine ◽  
Diagnostics System

The paper describes GE’s Remote Monitoring and Diagnostic (RM&D) system, its operation, its unique features and our experiences in applying it to improve performance and availability of heavy-duty gas turbine fleet worldwide. A key success factor of the system is that it relies upon an effective combination of advanced computer automation complemented by technical experts who have an in-depth understanding of the power generation equipment to achieve its objectives. The RM&D system enables GE experts to remotely access operational data of power plants operating world wide, and exercise sophisticated algorithms, which can detect abnormal operating conditions. The experts, with ready access to the design information, operation and maintenance information and in-depth knowledge about the turbines, identify and track operational signatures, which may indicate potential problems. The real key is to be able to distinguish false indications from the ones that are true early indicators of potential problems. In this paper we describe a design approach for developing a successful RM&D system. We illustrate our approach through various examples of performance, vibration and combustion diagnostics scenarios.

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).

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