Investigation of Blade and Disc Vibrations on the Upgraded Power Turbine for the THM 1304 Gas Turbine

2004 ◽  
Author(s):  
D. Frank ◽  
A. Kleinefeldt ◽  
U. Orth ◽  
W. Cline
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Turbine Blades ◽  
Mode Shapes ◽  
Experimental Investigations ◽  
Numerical Predictions ◽  
Power Turbine ◽  
Temperature Capability ◽  
Blade System ◽  
High Level

As part of an ongoing uprating and upgrading program of the THM 1304 gas turbine directed towards increasing power output and efficiency as well as further improving the high level of availability, major design modifications were made on the power turbine (PT). New blades and vanes were designed for increased aerodynamic efficiency, improved high temperature capability, higher power output and higher nominal operating speed. This report presents the analytical and experimental investigations made on the vibration modes and frequencies of blades with pre-loaded interlocking tip shrouds. One focus is upon observed families of mode shapes at different nodal diameters. A comparison of finite-element results with test data shows how good predictions are in the case of coupled blade vibrations. The value of testing the vibration behavior of power turbine blades in the actual machine, over the complete speed range, becomes evident as an important addition to the numerical predictions and laboratory tests. Another focus is on the method of testing, including the telemetry system used and the problem of optimum placement of strain gages on the blades. The selected strain gage positions are crucial to the value and meaningfulness of the test results. The observed strain vibration amplitudes were compared with high-cycle-fatigue (HCF) data available for the blade material. It was shown that measured amplitudes were significantly below allowable levels over the complete range of operating power and speed. The analytical and experimental methods employed to determine blade mode shapes and frequencies for a blade system with pre-loaded tip shrouds are presented in detail.

Development and Fabrication of Silicon Nitride Components for Ceramic Gas Turbine

1997 ◽  
Author(s):  
Keisuke Makino ◽  
Ken-Ichi Mizuno ◽  
Toru Shimamori
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
High Strength ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Spark Plug ◽  
Power Turbine

NGK Spark Plug Co., Ltd. has been developing various silicon nitride materials, and the technology for fabricating components for ceramic gas turbines (CGT) using theses materials. We are supplying silicon nitride material components for the project to develop 300 kW class CGT for co-generation in Japan. EC-152 was developed for components that require high strength at high temperature, such as turbine blades and turbine nozzles. In order to adapt the increasing of the turbine inlet temperature (TIT) up to 1,350 °C in accordance with the project goals, we developed two silicon nitride materials with further unproved properties: ST-1 and ST-2. ST-1 has a higher strength than EC-152 and is suitable for first stage turbine blades and power turbine blades. ST-2 has higher oxidation resistance than EC-152 and is suitable for power turbine nozzles. In this paper, we report on the properties of these materials, and present the results of evaluations of these materials when they are actually used for CGT components such as first stage turbine blades and power turbine nozzles.

An Experimental Investigation of the Flow in a 1½ Stage Axial Turbine With Regard to a High Level of Cooling-Air Injection

1999 ◽  
Author(s):  
U. Reinmöller ◽  
H. E. Gallus
Keyword(s):  
Film Cooling ◽  
Turbine Blades ◽  
Gas Injection ◽  
Leading Edge ◽  
Experimental Investigations ◽  
Flow Angle ◽  
Turbine Cooling ◽  
Flow Mixing ◽  
Reference Measurements ◽  
High Level

Experimental investigations of flow mixing due to film cooling of turbine blades have been performed. In a 1½-stage axial air turbine cooling gas (cool nitrogen down to −130 °C) was blown directly onto the leading edge of the first stator by special gas injector devices. In order to provide a database for the verification of numerical codes and to give an impression of the mixing process the gas has been injected at different radial positions. Furthermore the cooling massflow and cooling temperature were varied. The measuring data were obtained using pneumatic 5-hole probes with temperature sensors. The presented experimental data were simultaneous acquired in the planes behind both stators and the rotor. The results are compared and, discussed with reference measurements without cooling gas injection. It is shown that the effect of cooling gas injection is apparent in the wake of the first stator where it causes a small decrease in the pressure distribution as a result of increased flow mixing. Behind the first stator differences in the circumferentially averaged pitchwise flow angle due to the injected gas were not measured. Furthermore, temperature measurements clearly show the effect of the cooling gas injection in all planes. Even behind the second stator the different magnitudes of the temperature distribution are caused by the various injection of cooling gas.

Coupled Thermo-Mechanical Fatigue Tests for Simulating Load Conditions in Cooled Turbine Parts

2011 ◽  
Author(s):  
Roland Mu¨cke ◽  
Klaus Rau
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Mechanical Load ◽  
Fatigue Tests ◽  
Temperature Fields ◽  
Hot Gas ◽  
Mechanical Fatigue ◽  
Numerical Predictions ◽  
Temperature Capability ◽  
Load Conditions

Modern heavy-duty gas turbines operate under hot gas temperatures that are much higher than the temperature capability of nickel superalloys. For that reason, advanced cooling technology is applied for reducing the metal temperature to an acceptable level. Highly cooled components, however, are characterised by large thermal gradients resulting in inhomogeneous temperature fields and complex thermo-mechanical load conditions. In particular, the different rates of stress relaxation due to the different metal temperatures on hot gas and cooling air exposed surfaces lead to load redistributions in cooled structures, which have to be considered in the lifetime prediction methodology. In this context, the paper describes Coupled Thermo-Mechanical Fatigue (CTMF) tests for simultaneously simulating load conditions on hot and cold surfaces of cooled turbine parts, Refs [1, 2]. In contrary to standard Thermo-Mechanical Fatigue (TMF) testing methods, CTMF tests involve the interaction between hot and cold regions of the parts and thus more closely simulates the material behaviour in cooled gas turbine structures. The paper describes the methodology of CTMF tests and their application to typical load conditions in cooled gas turbine parts. Experimental results are compared with numerical predictions showing the advantages of the proposed testing method.

Centenary of the First Gas Turbine to Give Net Power Output: A Tribute to Ægidius Elling

2004 ◽  
Author(s):  
Lars E. Bakken ◽  
Kristin Jordal ◽  
Elisabet Syverud ◽  
Timot Veer
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Water Injection ◽  
Power Delivery ◽  
Compressed Air ◽  
Turbine Engine ◽  
Power Turbine ◽  
Clear Vision ◽  
Turbine Design ◽  
Net Power Output

The paper presents the work of the Norwegian engineer Ægidius Elling (ref. Figure 1), from his gas turbine patent in 1884 to the first gas turbine in the world producing net power in 1903. It traces the subsequent patents, until his final experiments in 1932. Focus is placed on an engineer with a clear vision of the potential of the gas turbine engine and the capability to realize his ideas, in spite of the lack of industrial financial support. In 1903, Elling noted in his diary that he thought he had built and operated the first gas turbine that could give net power delivery. The power delivery of this very first gas turbine was extracted as compressed air. The net power delivery was modest, only the equivalent of 11 hp. The reason for producing air was the accelerating use of pneumatic tools. Refinements to the gas turbine design soon followed, such as water injection for compressor cooling and recuperation of exhaust gas heat. In 1904, the power output of Elling’s gas turbine had increased to 44 hp. Elling also abandoned the production of compressed air in favor of electric power generation. In a patent from 1923, Elling described a multi-shaft engine with intercooling and reheat, with an independent power turbine. He improved this gas turbine in the period up to 1932, when the engine reached a power output of approximately 75 hp. In 1933, Elling wrote prophetically, “When I started to work on the gas turbine in 1882 it was for the sake of aeronautics and I firmly believe that aeronautics is still waiting for the gas turbine.” Unfortunately, Elling was never to take part in this development, although he pursued his work on the gas turbine until his death in 1949.

Analysis of the Scatter of the Elastic Properties in Conventionally Cast Nickel Base Superalloys: Quantification, Modeling and Evaluation of the Impact on Gas Turbine Blade Design

2014 ◽  
Author(s):  
Andrea Riva ◽  
Andrea Bessone
Keyword(s):  
Gas Turbine ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Turbine Blades ◽  
Mode Shapes ◽  
Elastic Behavior ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
The Impact

Cast nickel-base superalloys elastic properties have a very large scatter, mainly because of the coarse grain microstructure and in-grain anisotropy. This high dispersion must be taken into account in the design of gas turbine blades, in particular when evaluating phenomena directly linked to the elastic behavior, such as blades vibration. This source of elastic properties scatter becomes even more important on specimens for material characterization because of their inferior size, which entails a lesser number of grains (i.e. a larger scatter). In this paper a model aimed to quantify such scatter is proposed. The performances of the model in predicting the standard deviation of the Young’s modulus (and consequently of the eigenfrequencies) are also shown, both for tested specimens and blades excited on clamps. Finally, a sensitivity FEM modal analysis is performed in order to evaluate how the elastic property dispersion might affect the blade eigenfrequencies and the relative mode shapes, with particular emphasis on the case of a specific region of a geometrically complex component affected by an anomalous Young’s modulus. Besides, the influence of the blade mass is evaluated through both experimental clamp impact tests and FEM analyses. The effect on blades of such source of scatter is then compared to the effect of the elastic properties dispersion. ANSYS program has been used for the simulations.

scholarly journals Investigating of Turbine Blades Geometrical Change Effects on Dynamic Performance of IGT-25 Gas Turbine

2019 ◽  
Author(s):  
Nima Zamani Meymian ◽  
Hossein Rabiei
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Turbine Blades ◽  
Gas Generator ◽  
Air Compressor ◽  
Power Turbine ◽  
Geometrical Change

In the paper, the effect of gas generator turbine blades’ geometrical change has been studied on the overall performance of a twin-shaft 25MW gas turbine with industrial application, under dynamic conditions. Geometrical changes include change of thickness and height of gas generator turbine blades which in turn would result in the change in the mass flow rate of passing hot gas, as well as isentropic efficiency in each stage of the turbine. Gas turbine modeling in the paper is zero-dimensional and takes place with consideration of dynamic effects of volume on air compressor components, combustion chamber, gas generator turbine, power turbine, fuel system, as well as effects of heat transfer dynamics between blades, gas path, and effects of operators on inlet guide vanes, fuel valves, and air compressor discharge valve. In the mathematical model of each of the components, steady-state characteristics curves have been used, extracted from 3-Dimensional computational fluid dynamics (CFD). To do so, characteristic curves of the first and second stages of the four-stage turbine have been updated through 3-D fluid dynamic analysis so that the effect of geometrical changes in turbine blades would be applied. Results from effects of these changes on characteristics of transient gas flow including output power of gas generator turbine and power turbine, inlet and outlet temperatures of turbine stages, as well as air and fuel mass flow rates have been provided from the start-ups until reaching the nominal load would be achieved.

scholarly journals Gas Turbine Blade Stress Analysis and Mode Shape Determination Using Thermoelastic Methods

2008 ◽  
Vol 13-14 ◽  
pp. 281-287 ◽  
Author(s):  
David Backman ◽  
R.J. Greene
Keyword(s):  
Stress Analysis ◽  
Gas Turbine ◽  
Surface Stress ◽  
Infrared Detector ◽  
Turbine Blades ◽  
Thermoelastic Stress ◽  
Mode Shapes ◽  
Gas Turbine Blades ◽  
Cyclic Displacement ◽  
Selection Of

The efficacy of thermoelastic stress analysis for use in the study of moderately curved gas turbine blades is considered over a frequency range of 68 Hz to 3.4 kHz. A selection of blades, both industrial examples and simplified planar laboratory specimens, are excited at their natural vibration frequencies using both electromagnetic shakers and piezoelectric stack actuators, in order to develop a cyclic displacement of the blade surface and hence a cyclic variation in surface stress condition. Results are shown using both snapshot array and rolling array infrared detector systems, and the data then used to generate maps of normalized principal surface stress sum, and hence the mode shapes of vibration, including the first four excitation modes.

Design Optimization and Validation of a Power Turbine Blade for an Aero-Derivative Gas Turbine Upgrade

2008 ◽  
Author(s):  
Paolo Del Turco ◽  
Michele D’Ercole ◽  
Nicola Pieroni ◽  
Massimiliano Mariotti ◽  
Francesco Gamberi ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Material Selection ◽  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Industrial Applications ◽  
Initial Assessment ◽  
Limiting Factor ◽  
Cycle Fatigue ◽  
Power Turbine

Major limitations for power turbine blades for oil & gas and industrial applications are Creep and HCF (High Cycle Fatigue). Power Turbine blades, being normally uncooled, are generally not affected by high temperature gradients; therefore LCF (Low Cycle Fatigue) doesn’t constitute their main limiting life factor. If creep is often not a limiting factor for aircraft engines blades, where inspection, maintenance and replacement intervals are more frequent, it becomes one of the key drivers for an industrial gas turbine where required flow path components life is at least one order larger. To avoid HCF failures, it would be desirable to avoid stimuli crossing natural frequencies in the entire operative range. However, due to the wide operative range and high number of stimuli present, the avoidance of potential resonance crossings is often not possible. This is the one of the reasons why a prototype validation campaign is usually performed, where, during the test, vibratory stress levels are compared to HCF endurance limits. This paper describes the processes used in GE Infrastructure Oil&Gas to verify, design, develop and test a PT (Power Turbine) blade for an upgraded 35 MW-class aero-derivative gas turbine. Initial assessment phases, new material selection, concurrent engineering efforts, bench testing characterization and final validation on FETT (First Engine to Test) are described. A particular focus is given to the analytical tools (i.e. modal cyclic symmetry analysis) used during the design phase and validation tests.

Power Turbine Dynamics: An Evaluation of a Shear-Mounted Elastomeric Damper

1983 ◽  
Author(s):  
E. S. Zorzi ◽  
J. Walton ◽  
R. Cunningham
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Roller Bearing ◽  
Turbine Rotor ◽  
Mode Shapes ◽  
Squeeze Film ◽  
Axial Thrust ◽  
Turbine Engine ◽  
Power Turbine ◽  
Damper Design

The safe and reliable operation of high-speed rotating machinery often requires the use of devices that dissipate undesirable rotor vibrations. As an alternative to the more conventional squeeze-film bearing damper designs, a Viton-70 shear-mounted, elastomeric damper was built and tested in a T-55 power turbine high-speed balancing rig. This application demonstrated, for the first time, the feasibility of using elastomers as the primary rotor damping source in production turbine engine hardware. The shear-mounted damper design was selected because of its compatibility with actual gas turbine engine radial space constraints, its accommodation of both the radial and axial thrust loads present in gas turbine engines, and its capability of controlled axial preload. The shear-mounted damper was interchangeable with the production T-55 power turbine roller bearing support so that a direct comparison between the shear damper and the production support structure could be made. Test results showed that the Viton-70 elastomeric damper operated successfully and provided excellent control of both synchronous and nonsynchronous vibrations through all phases of testing to the maximum rotor speed of 1676 rad/s (16,000 rpm). Excellent correlation between the predicted and experienced critical speeds, mode shapes, and log decrements for the power turbine rotor and elastomer damper assembly was also achieved.

Variable Regimes Operation of Cogenerative Gas-Turbine Engine With Overexpansion Turbine

2010 ◽  
Author(s):  
V. Matviienko ◽  
V. Ocheretianyi
Keyword(s):  
Gas Turbine ◽  
Electrical Power ◽  
Electrical Energy ◽  
High Energy ◽  
Gas Turbine Engine ◽  
Energetic Efficiency ◽  
Turbine Engine ◽  
Power Turbine ◽  
Turbo Compressor ◽  
High Level

High energetic efficiency of cogenerative gas-turbine engine (GTE) is due to by deep utilization of exhaust gases heat and greater portion of produced electrical energy, with is achieved by complication of Brayton cycle application of overexpansion in turbine. Such method is realized in GTE with turbo-compressor utilizer (TCU) attached to exhaust of the engine. TCU consists of the overexpansion turbine, exhaust compressor and gas cooler between them. Gas cooler in TCU is used as a water boiler-utilizer. This paper presents characteristics of GTE with TCU in variable regimes of loading. It is found, that GTE with TCU at nominal and partial loadings has higher efficiency, than simple cycle GTE. Construction of GTE with TCU can be performed with free TCU and blocked TCU, which is mechanically linked to power turbine. High energy efficiency of GTE with free TCU is proved, enabling to maintain overall efficiency on high level on decrease of electrical power. It is suggested that GTE with free TCU is more efficient for energy supply of municipal objects, and its constructive scheme provides stable delivery of heat energy to consumer upon significant variation of electric loading.

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