Evaluation of Foil Bearing Performance and Nonlinear Rotordynamics of 120 kW Oil-Free Gas Turbine Generator

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Daejong Kim ◽  
An Sung Lee ◽  
Bum Seog Choi
Keyword(s):  
Frequency Domain ◽  
Gas Turbine ◽  
Turbine Rotor ◽  
Gas Generator ◽  
Turbine Generator ◽  
Element Analysis ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Nonlinear Transient ◽  
Stiffness And Damping

This paper presents a design approach of air foil bearings (AFBs) for a 120 kWe gas turbine generator, which is a single spool configuration with gas generator turbine and alternator rotor connected by a diaphragm coupling. A total of four radial AFBs support the two rotors, and one set of double acting thrust foil bearing is located inside the gas generator turbine. The rotor configuration results in eight degree of freedom (DOF) rotordynamic motions, which are two cylindrical modes and two conical modes from the two rotors. Stiffness of bump foils of candidate AFB was estimated from measured structural stiffness of the bearing, and implemented to the computational model for linear stiffness and damping coefficients of the bearing and frequency-domain modal impedances for cylindrical and conical modes. Stiffness of the diaphragm coupling was evaluated using finite element analysis and implemented to nonlinear rotordynamic analyses of the entire engine. Analyses show the conical mode of the turbine rotor is the main source of instability of the entire engine when AFB clearance is not selected properly. Optimum AFB clearance is suggested from frequency domain modal analyses and nonlinear transient analyses.

Evaluation of Foil Bearing Performance and Nonlinear Rotordynamics of 120kW Oil-Free Gas Turbine Generator

2013 ◽  
Author(s):  
Daejong Kim ◽  
An Sung Lee ◽  
Bum Seog Choi
Keyword(s):  
Frequency Domain ◽  
Gas Turbine ◽  
Turbine Rotor ◽  
Gas Generator ◽  
Turbine Generator ◽  
Element Analysis ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Nonlinear Transient ◽  
Stiffness And Damping

This paper presents design approach of air foil bearings (AFBs) for 120kWe gas turbine generator, which is a single spool configuration with gas generator turbine and alternator rotor connected by a diaphragm coupling. Total four radial AFBs support the two rotors, and one set of double acting thrust foil bearing is located inside the gas generator turbine. The rotor configuration results in eight degree of freedom (DOF) rotordynamic motions, which are two cylindrical modes and two conical modes from the two rotors. Stiffness of bump foils of candidate AFB was estimated from measured structural stiffness of the bearing, and implemented to computational model for linear stiffness and damping coefficients of the bearing and frequency-domain modal impedances for cylindrical and conical modes. Stiffness of the diaphragm coupling was evaluated using finite element analysis and implemented to non-linear rotordynamic analyses of entire engine. Analyses show conical mode of turbine rotor is the main source of instability of entire engine when AFB clearance is not selected properly. Optimum AFB clearance is suggested from frequency domain modal analyses and nonlinear transient analyses.

Test Experience With Turbine-End Foil Bearing Equipped Gas Turbine Engines

1983 ◽  
Author(s):  
F. J. Suriano ◽  
R. D. Dayton ◽  
Fred G. Woessner
Keyword(s):  
Gas Turbine ◽  
Thermal Environment ◽  
Full Range ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Engine Test ◽  
Gas Generator ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Foil Bearing

The Garrett Turbine Engine Company, a Division of the Garrett Corporation, authorized under Air Force Contract F33615-78-C-2044 and Navy Contract N00140-79-C-1294, has been conducting development work on the application of gas-lubricated hydrodynamic journal foil bearings to the turbine end of gas turbine engines. Program efforts are directed at providing the technology base necessary to utilize high-temperature foil bearings in future gas turbine engines. The main thrust of these programs was to incorporate the designed bearings, developed in test rigs, into test engines for evaluation of bearing and rotor system performance. The engine test programs included a full range of operational tests; engine thermal environment, endurance, start/stops, attitude, environmental temperatures and pressures, and simulated maneuver bearing loadings. An 88.9 mm (3.5-inch) diameter journal foil bearing, operating at 4063 RAD/SEC (38,800 rpm), has undergone test in a Garrett GTCP165 auxiliary power unit. A 44.4 mm (1.75-inch) diameter journal foil bearing, operating at 6545 RAD/SEC (62,500 rpm) has undergone test in the gas generator of the Garrett Model JFS190. This paper describes the engine test experience with these bearings.

The Application of Gas- and Oil-Lubricated Foil Bearings for the ERDA/Chrysler Automotive Gas Turbine Engine

1976 ◽  
Author(s):  
S. Gray ◽  
N. Sparks ◽  
J. McCormick
Keyword(s):  
Gas Turbine ◽  
Cost Savings ◽  
Turbine Rotor ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Rotor Bearing ◽  
Dynamic Simulator ◽  
And Performance ◽  
Engine Rotor

A design study has been made of a resilient hydrodynamic foil bearing support system for a 58,500-rpm automotive gas turbine rotor utilizing an air-lubricated journal bearing at the hot turbine end and an oil-lubricated journal and thrust bearing at the compressor end. The paper includes a review of earlier engine rotor/bearing systems and lists the potential advantages of the foil bearings. Design analysis of the bearings and rotordynamics is given including critical speeds, rotor unbalance response, bearing performance, and temperature distributions to confirm the feasibility. The study shows that potential improvements to the overall system in terms of cost savings, reliability, and performance are possible. Full-scale dynamic simulator testing of the rotor bearing system as designed is in progress.

Development US Navy Gas Turbine Vibration Analysis Expertise: LM2500 Vibration and Trim Balance

2012 ◽  
Author(s):  
Bruce D. Thompson ◽  
Jurie Grobler
Keyword(s):  
Gas Turbine ◽  
Turbine Rotor ◽  
Gas Generator ◽  
Engine Operation ◽  
Engine Design ◽  
Power Turbine ◽  
Us Navy ◽  
Continued Use ◽  
Integrated Performance ◽  
Mean Time

Although generally reliable in-service and with an ever increasing mean time between removal, it was identified in the mid to late 1980’s that the LM2500 gas turbine in US Navy service had a problem with self generated vibration; this was principally due to imbalance in the gas generator or power turbine rotor, however, other non-synchronous sources for vibration were discovered to be important as well. The initial method for resolving this problem was to remove and repair, at a depot, the engines that exceeded the in-service alarm level. This turned out to be a very expensive approach and it was found that most engines that had excessive vibration levels in other respects (performance, etc.) were perfectly acceptable for continued use without repair. Raising the vibration alarm level was tried for a time. However, it became clear that prolonged engine operation with higher levels of vibration were detrimental to the mechanical integrity of the engine. This paper discusses the systematic approach developed to reduce LM2500 self generated vibration levels. This included monitoring system improvements, engine design & hardware improvements and the development and implementation of in-place trim balance. This paper also discusses some of the analysis and practical difficulties encountered reducing and maintaining low LM2500 vibration levels through trim balance and by other means. Also discussed is the present implementation of remotely monitoring LM2500 operating parameters, in particular vibration, through the Integrated Performance Analysis Reports (IPAR) and the Maintenance Engineering Library Server (MELS).

Turbine Rotor Tooth Head and Stress Analysis of Wedge

2013 ◽  
Vol 395-396 ◽  
pp. 856-861
Author(s):  
Li Li Zhao
Keyword(s):  
Structural Design ◽  
Turbine Rotor ◽  
Structure Modification ◽  
Ansys Software ◽  
Turbine Generator ◽  
Element Analysis ◽  
Generator Rotor ◽  
The Stability ◽  
Rotor Tooth ◽  
Rotor Structure

The turbine generator rotor and the wedge is an important part of the turbogenerator. In order to ensure the stability and reliability of the steam turbine during operation, it needs to calculate and analyze the strength of the generator rotor and the wedge. In this paper, we did the study of the turbine generator rotor and the strength of the wedge by finite element analysis. by using ANSYS software, when in operating speed and speeding, we compared to the results of the calculation of plane and solid elements, and found that the safety factor of the plane was lower. Based on the results of two calculations, we got the generator rotor structure modification and optimization of the structural design, which improve the strength of the generator rotor tooth head and wedge.

scholarly journals Analisis Efektivitas Gas Turbine Generator dengan Metode Overall Equipment Effectiveness

2019 ◽  
Vol 5 (1) ◽  
pp. 7
Author(s):  
M. Sayuti ◽  
Silvira Maulinda
Keyword(s):  
Production Process ◽  
Gas Turbine ◽  
Chemical Industry ◽  
Business Processes ◽  
Gas Generator ◽  
Turbine Generator ◽  
Large Space ◽  
Turbine Generators ◽  
Production Effectiveness ◽  
Main Production

Increasing effectiveness is very important for companies to obtain success in their business processes. One example of increasing effectiveness is by evaluating the performance of production facilities in the company. PT. X is one of the chemical industry companies whose main production is urea fertilizer. One of the supporting processes of the production process is the Gas Turbine Generator (GTG) in the utility unit. In supporting the production process, GTG often experiences problems that directly hinder the production process. This study aims to analyze the effectiveness of Gas Turbine Generators by using the Overall Equipment Effectiveness (OEE) method. The results of the analysis show that the Turbine Gas Generator effectiveness level is 68.39% which indicates that the value of production effectiveness is considered reasonable, but shows there is a large space for improvement.

A new computational method for predicting the thermal bow of a rotor

2018 ◽  
Vol 233 (12) ◽  
pp. 4372-4380 ◽  
Author(s):  
M Zhuo ◽  
LH Yang ◽  
K Xia ◽  
L Yu
Keyword(s):  
Analytical Solution ◽  
Gas Turbine ◽  
Turbine Rotor ◽  
Computational Method ◽  
Practical Significance ◽  
Complex Structures ◽  
Heavy Duty ◽  
Element Analysis ◽  
First Order ◽  
Heavy Duty Gas Turbine

In a heavy-duty gas turbine, when hot rotor is left cooled in standstill condition, thermal bow occurs due to natural convection, which may result in high vibrations in a subsequent restart. Usually, a turning gear is immediately started after shutdown of gas turbine to slowly roll and uniformly cool the rotor in order to prevent thermal bow, which is called turning gear operation. The minimum turning time and the acceptable temperature of wheel space are two important indexes of turning gear operation, and their determination highly depends on accurate prediction of thermal bow. This paper proposes an analytical method to predict the thermal bow behavior of rotors with complex structures and investigates the effect of turning time on thermal bow. First, the general form of analytical solution of rotor thermal bow is derived and validated through both finite element analysis and experiments. Then the analytical solution is applied in a heavy-duty gas turbine to predict the most severe thermal bow behavior of the rotor with no turning gear in operation before standstill. Finally, the effect of turning time on thermal bow is investigated, and the indexes to achieve acceptable thermal bow are discussed. Results show that the shape of thermal bow of the gas turbine rotor is close to the first-order mode shape; the peak of the most severe thermal bow reaches 0.7 mm after 3.8 h of cooling and the decrease of thermal bow is much slower than the increase. Besides, the maximum thermal bow of the rotor due to insufficient turning gear operation presents an exponential decay with turning time and lies in linear relationship with the temperature of the same location. These two relationships help determine the minimum turning time and acceptable temperature of wheel space to attain an acceptable bow and thus have practical significance to develop and optimize turning gear operations.

A Comparison of the Steady-State and Dynamic Performance of First- and Second-Generation Foil Bearings

2010 ◽  
Author(s):  
M. J. Conlon ◽  
A. Dadouche ◽  
W. M. Dmochowski ◽  
R. Payette ◽  
J.-P. Be´dard
Keyword(s):  
Steady State ◽  
Experimental Evaluation ◽  
First Generation ◽  
Second Generation ◽  
Load Capacity ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Stiffness And Damping

Oil-free foil bearing technology has advanced intermittently over the years, driven by research efforts to improve both steady-state and dynamic performance characteristics, namely: load capacity, stiffness, and damping. Bearing designs are thus classified according to “generation”, with first-generation bearings being the most primitive. This paper presents an experimental evaluation of a first- and a second-generation foil bearing, and aims to provide the high-fidelity data necessary for proper validation of theoretical predictive models of foil bearing performance. The aforementioned test bearings were fabricated in-house, and are both 70mm in diameter with an aspect ratio of 1; bearing manufacturing details are provided. The work makes use of a facility dedicated to measuring both the steady-state and dynamic properties of foil bearings under a variety of controlled operating conditions. The bearing under test is placed at the midspan of a horizontal, simply-supported, stepped shaft which rotates at up to 60krpm. Static and dynamic loads of up to 3500N and 450N (respectively) can be applied by means of a pneumatic cylinder and two electrodynamic shakers. The bearings’ structural (static) stiffnesses are highly nonlinear, and this affects the accuracy of the dynamic coefficient determination. Both dynamic stiffness and damping are found to vary nonlinearly with excitation frequency, and are over-predicted by a structural experimental evaluation — the film plays an important role in bearing dynamics. The second-generation bearing is found to have a higher load capacity, dynamic stiffness, and damping than the first-generation bearing.

Effect of Circumferential Location of Radial Injection on Rotordynamic Performance of Hybrid Air Foil Bearings

2018 ◽  
Author(s):  
Behzad Zamanian Yazdi ◽  
Daejong Kim
Keyword(s):  
Time Domain ◽  
High Speed ◽  
Substantial Improvement ◽  
Reliable Operation ◽  
Foil Bearings ◽  
Damping Coefficients ◽  
Foil Bearing ◽  
Radial Injection ◽  
Parametric Studies ◽  
Stiffness And Damping

Air foil bearings (AFBs) are introduced as promising bearings for oil-free turbomachinery applications. AFBs provide reliable operation at high speed and high temperature with negligible power loss. Hybrid Air Foil Bearing (HAFB) technology utilizes the radial injection of externally pressurized air into the traditional hydrodynamic AFB’s film thickness through orifices attached to the top foil. Previous studies have reported enhancement in the rotordynamic stability of HAFBs compared to traditional hydrodynamic AFBs. HAFBs have several orifices distributed in the circumferential direction. In this study, the effect of the circumferential location of radial injection on the rotordynamic performance of the rotor-HAFB is studied. Analytical and experimental evaluations of the rotordynamic performance of a rotor supported by two single-pad HAFBs are presented. Parametric studies are conducted using three sets of single-pad HAFBs. The circumferential locations of orifices are different for each set. The presented simulation analyses consist of time-domain orbit simulation and frequency-domain modal analysis. Imbalance responses of rotor-HAFB were measured with various orifice locations and the results agree well with predictions. Comparison of the rotordynamic performance of HAFBs with different orifice configurations demonstrate substantial improvement in rotordynamic stability as well as enhancement in the stiffness and damping coefficients of HAFBs by choosing the best circumferential location for radial injection to control rotor eccentricity and attitude angle.

Dynamic Stiffness and Damping of Foil Bearings for Gas Turbine Engines

1993 ◽  
Author(s):  
Walter L. Meacham ◽  
R. M. Fred Klaass ◽  
Ron Dayton ◽  
Ed Durkin
Keyword(s):  
Gas Turbine ◽  
Dynamic Stiffness ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Foil Bearings ◽  
Stiffness And Damping
Sign in / Sign up

Export Citation Format

Share Document