Evaluation of a Gas-Lubricated Foil Bearing for Control of Gas Turbine Engine Rotor Critical Speeds

1975 ◽  
Author(s):  
R. H. Badgley ◽  
J. Reddecliff
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Critical Speeds ◽  
Foil Bearing ◽  
Engine Rotor

Effect of long service on the fine structure of the surface of gas turbine engine rotor blades

1977 ◽  
Vol 9 (10) ◽  
pp. 1257-1261
Author(s):  
O. I. Marusii ◽  
Yu. I. Koval' ◽  
E. N. Kaspruk ◽  
V. N. Torgov
Keyword(s):  
Fine Structure ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Rotor Blades ◽  
Turbine Engine ◽  
Engine Rotor

Three-Dimensional Structural Evaluation of a Gas Turbine Engine Rotor

2014 ◽  
Author(s):  
Partha S. Das
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Complex Geometries ◽  
Turbine Engine ◽  
Industrial Gas Turbine ◽  
Engine Rotor ◽  
Engine Rotors ◽  
Critical Locations

Engine rotors are one of the most critical components of a heavy duty industrial gas turbine engine, as it transfers mechanical energy from rotor blades to a generator for the production of electrical energy. In general, these are larger bolted rotors with complex geometries, which make analytical modeling of the rotor to determine its static, transient or dynamic behaviors difficult. For this purpose, powerful numerical analysis approaches, such as, the finite element method, in conjunction with high performance computers are being used to analyze the current rotor systems. The complexity in modeling bolted rotor behavior under various loadings, such as, airfoil, centrifugal and gravity loadings, including engine induced vibration is one of the main challenges of simulating the structural performance of an engine rotor. In addition, the internal structural temperature gradients that can be encountered in the transient state as a result of start-up and shutdown procedures are generally higher than those that occur in the steady-state and hence thermal shock is important factor to be considered relative to ordinary thermal stress. To address these issues, the current paper presents the steady-state & quasi-static analyses (to approximate transient responses) of two full 3-D industrial gas turbine engine rotors, SW501F & GE-7FA rotor, comprising of both compressor & turbine sections together. Full 3-D rotor analysis was carried out, since the 2-D axisymmetric model is inadequate to capture the complex geometries & out of plane behavior of the rotor. Both non-linear steady-state & transient analyses of a full gas turbine engine rotor was performed using the general purpose finite element analysis program ABAQUS. The paper presents in detail the FEA modeling technique, overall behavior of the full rotor under various loadings, as well as, the critical locations in the rotor with respect to its strength and life. The identification of these critical locations is needed to help with the repair of the existing rotors and to improve and extend the operational/service life of these rotors.

Small Gas Turbine Engine Operating With High-Temperature Foil Bearings

2006 ◽  
Author(s):  
Hooshang Heshmat ◽  
Michael J. Tomaszewski ◽  
James F. Walton
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Critical Speed ◽  
Ball Bearing ◽  
Gas Turbine Engine ◽  
System Stability ◽  
Exhaust Gas ◽  
Turbine Engine ◽  
Foil Bearing ◽  
Bearing Life

A 134 Newton thrust class, 120,000 rpm turbojet was redesigned to incorporate a high-temperature compliant foil bearing aft of the turbine rotor and a compliantly mounted ball bearing forward of the centrifugal compressor–cold section. Two rotor-bearing system configurations were evaluated, one for operation above the bending critical speed and one for rigid rotor operation. Required characteristics for the foil bearing and ball bearing equipped with compliant foil damper mount were determined through a series of design tradeoff studies evaluating critical speeds and system stability. Following the design studies, the necessary hardware was fabricated, the engine assembled and operation to full speed achieved. Engine speed, rotor vibrations, compressor discharge pressure, exhaust gas temperature, thrust and fuel consumption were all recorded for both a baseline fluid lubricated ball bearing supported engine and the new turbojet engine using the hybrid foil bearing support system. Issues related to high-speed operation above the bending critical speed are identified and recommendations offered. Engine test data show that approximately 10% less fuel is consumed by the hybrid foil bearing mount system than the baseline conventional design. It is also shown that the foil bearing life was longer than the ball bearing life even though the foil bearing operated in the exhaust gas stream at temperatures exceeding 800°C. The results of this program demonstrate the feasibility of developing a completely oil-free foil bearing gas turbine engine.

The Potential Impact of Multiplane-Multispeed Balancing on Gas Turbine Production and Overhaul Costs

1975 ◽  
Vol 97 (3) ◽  
pp. 347-353 ◽  
Author(s):  
R. H. Badgley
Keyword(s):  
Gas Turbine ◽  
Cost Effective ◽  
Gas Turbine Engine ◽  
Single Step ◽  
Potential Cost ◽  
Turbine Engine ◽  
Critical Speeds ◽  
Cost Effective Method ◽  
Bearing Assembly ◽  
Potential Impact

This paper describes recent advances in the development of a practical, cost-effective method for balancing, in a single step, a final shaft-bearing assembly simultaneously in a number of planes and at a number of speeds. This method is capable of overcoming assembly-introduced unbalance, and will permit rotor operation through critical speeds in which component elastic axis bending occurs. Detailed results of test efforts are presented in order to illustrate the effectiveness of the method. The procedure by which the method may be applied to gas turbine engine shafts, and the potential cost advantages expected to accrue therefrom, are described and discussed.

Optimization of a Gas Turbine Engine Rotor Disc Using Case-Based Reasoning and the GATE Genetic Algorithm

2010 ◽  
Author(s):  
S. Dominique ◽  
J.-Y. Tre´panier
Keyword(s):  
Genetic Algorithm ◽  
Gas Turbine ◽  
Structural Design ◽  
Gas Turbine Engine ◽  
Pattern Search ◽  
Case Based Reasoning ◽  
Turbine Engine ◽  
Local Searches ◽  
Case Based ◽  
Engine Rotor

The implementation of an automated decision support system in the field of structural design and optimization can give a significant advantage to any industry working on mechanical design. Such a system can reduce the project cycle time or allow more time to produce a better design by providing solution ideas to a designer or by upgrading existing design solutions while the designer is not at work. This paper presents an approach to automating the process of designing a gas turbine engine rotor disc using case-based reasoning (CBR), combined with a new genetic algorithm, the Genetic Algorithm with Territorial core Evolution (GATE). GATE was specifically created to solve problems in the mechanical structural design field, and is essentially a real number genetic algorithm that prevents new individuals from being born too close to previously evaluated solutions. The restricted area becomes smaller or larger during optimization to allow global or local searches when necessary. The CBR process uses a databank filled with every known solution to similar design problems. The closest solutions to the current problem in terms of specifications are selected, along with an estimated solution from an artificial neural network. Each solution selected by the CBR is then used to initialize the population of a GATE island. Our results show that CBR may significantly upgrade the performance of an optimization algorithm when sufficient preliminary information is known about the design problem. It provides an average solution 5.0% lighter than the average solution found using random initialization. The results are compared to other results obtained for the same problems by four optimization algorithms from the I-SIGHT 3.5 software: the sequential quadratic programming algorithm (SQP), the insular genetic algorithm (GA), the Hookes & Jeeves generalized pattern search (HJ) and POINTER. Results show that GATE can be a very good candidate for automating and accelerating the structural design of a gas turbine engine rotor disc, providing an average disc 18.9% lighter than SQP, 11.2% lighter than HJ, 23.9% lighter than GA and 4.3% lighter than POINTER, even when starting with the same solution set.

Application of an Advanced Hybrid Rotordynamics Model to the Complete Structure of a Marine Gas Turbine Engine

1988 ◽  
Vol 110 (4) ◽  
pp. 578-584 ◽  
Author(s):  
B. D. Thompson ◽  
R. H. Badgley
Keyword(s):  
Gas Turbine ◽  
Structural Response ◽  
Gas Turbine Engine ◽  
Mode Shapes ◽  
Structural Flexibility ◽  
Turbine Engine ◽  
Critical Speeds ◽  
Structural Support ◽  
Engine Vibration ◽  
Vibration Problems

Extensive fleet experience with the LM2500 marine gas turbine engine has identified it as an engine that exhibits wear-accelerating vibration effects. The critical speeds and associated mode shapes were not well understood by U.S. Navy engineers. To help deal with vibration-related problems, an analytical model was developed to calculate engine rotordynamic and structural response. The procedure is a multilevel, multirotor hybrid extension of the classical Myklestad-Prohl method. Presented herein are some of the model’s predictions, and correlations with actual engine vibration measurements. The model predicted in excess of 20 different critical speeds in the engine’s operating range. Because of the engine’s structural flexibility, most of the critical speeds were engine casing and structural support resonances, driven by imbalance or misalignment in one or both of the engine rotors. Rotor-bending critical speeds were found to be strongly influenced by engine casing and support structure stiffness and mass. Using the model’s predicted mode shapes, new mounting locations for accelerometers could be selected to determine vibration severity at various frequencies better. This has given the U. S. Navy new insights into fleet vibration problems, and provides a useful tool for achieving reduced engine removals.

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