scholarly journals High-Speed Rotor Suspension Formed by Fully Floating Hydrodynamic Radial and Thrust Bearings

1963 ◽  
Author(s):  
Juraj Dworski
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Critical Speed ◽  
Vibrational Excitation ◽  
Turbine Rotor ◽  
Continuous Operation ◽  
Flexible Rotor ◽  
Actual System ◽  
Apparent Absence ◽  
Thrust Bearings

The hydrodynamic suspension of a 44,000-rpm gas-turbine rotor is described with emphasis on interaction between the flexible rotor and its supports. Bearings with relatively large clearances are shown to allow continuous operation at the rotor first critical speed of 22,000 rpm. The apparent absence of hydrodynamic system instabilities is attributed to the use of simple floating-sleeve bearings. A parametric study of the influence of bearing clearances upon vibrational excitation relief is presented together with test data collected on actual system hardware.

High-Speed Rotor Suspension Formed by Fully Floating Hydrodynamic Radial and Thrust Bearings

1964 ◽  
Vol 86 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Juraj Dworski
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Critical Speed ◽  
Vibrational Excitation ◽  
Turbine Rotor ◽  
Continuous Operation ◽  
Flexible Rotor ◽  
Actual System ◽  
Apparent Absence ◽  
Thrust Bearings

The hydrodynamic suspension of a 44,000-rpm gas turbine rotor is described with emphasis on interaction between the flexible rotor and its supports. Bearings with relatively large clearances are shown to allow continuous operation at the rotor first critical-speed of 22,000 rpm. The apparent absence of hydrodynamic system instabilities is attributed to the use of simple floating-sleeve bearings. A parametric study of the influence of bearing clearances upon vibrational excitation relief is presented together with test data collected on actual system hardware.

Optimization Design and Experimental Study of a Two-disk Rotor System Based on Multi-Island Genetic Algorithm

2019 ◽  
Vol 36 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Jingjing Huang ◽  
Longxi Zheng ◽  
Chris K Mechefske ◽  
Bingbing Han
Keyword(s):  
Genetic Algorithm ◽  
Vibration Amplitude ◽  
High Speed ◽  
Optimization Design ◽  
Critical Speed ◽  
Optimization Method ◽  
Rotor System ◽  
Flexible Rotor ◽  
Optimum Position ◽  
Transient Experiments

Abstract Based on rotor dynamics theory, a two-disk flexible rotor system representing an aero-engine with freely supported structure was established with commercial software ANSYS. The physical model of the two-disk rotor system was then integrated to the multidisciplinary design optimization software ISIGHT and the maximum vibration amplitudes experienced by the two disks when crossing the first critical speed were optimized using a multi-island genetic algorithm (MIGA). The optimization objective was to minimize the vibration amplitudes of the two disks when crossing the first critical speed. The position of disk 1 was selected as the optimization variable. The optimum position of disk 1 was obtained at the specified constraint that the variation of the first critical speed could not exceed the range of ±10 %. In order to validate the performance of the optimization design, the proof-of-transient experiments were conducted based on a high-speed flexible two-disk rotor system. Experimental results indicated that the maximum vibration amplitude of disk 1 when crossing the first critical speed declined by 60.9 % and the maximum vibration amplitude of disk 2 fell by 63.48 % after optimization. The optimization method found the optimum rotor positions of the flexible rotor system which resulted in minimum vibration amplitudes.

Technology for Straightening the Bent GT Rotor

2011 ◽  
Author(s):  
Yongxiang Zhu ◽  
Jinming Leng ◽  
Shidong Tang
Keyword(s):  
Detailed Analysis ◽  
Gas Turbine ◽  
High Speed ◽  
Turbine Rotor

The GT rotor is composed of a plurality of discs and two shafts. The GT gas turbine rotor may be bent after assembled because of each part has its geometric tolerance.The scheme must be carry out to straight the bend rotor. In oder to get well high speed balance, the surface of each disc excircle, torque tube and disc adaptor can’t be remachine on lath after assemble. We can machine the journal of the shaft on horizontal lathe to straight the slightly bended rotor. For the serious bended rotor, we must disassemble the rotor and change the parallelism of two side of the disc flange on vertical lathe to get a straight rotor. This attic detailed analysis these two schemes and proposed specific actions measures, then the problem of how to straight a bent GT rotor get well solution.

Repair and Rejuvenation of a Severely Damaged 16-Stage Steam Turbine Rotor

2009 ◽  
Author(s):  
S. Ingistov ◽  
R. K. Bhargava ◽  
G. Doerksen
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
Repair Process ◽  
Turbine Rotor ◽  
Recent Experience ◽  
Replacement Cost ◽  
Flexible Rotor ◽  
Steam Turbine Rotor ◽  
Corrosion Pitting ◽  
Center Section

This paper describes the recent experience with the extensive overhaul and repairs of a long and flexible 16-stage steam turbine rotor of an integral design. An integral design steam turbine rotor is one where the shaft and disks are machined from a single forging. The steam turbine had sustained a crack at the base of the 11th stage disk as well as moderate to extensive corrosion pitting throughout the center section (stages 5 to 8) of the rotor. The rim of the 6th stage disk also required rebuilding because of the excessive damage due to corrosion and pitting. The steps required to optimize the repair process and minimize repair time as well as precautions taken during the repairs are discussed in this paper. To ensure reliability of the rebuild work, including newly manufactured blades for the 6th stage disk, stress analysis using Finite Element Method (FEM) was used to verify that stress levels are within acceptable limits in the blade’s root-to-dovetail groove, the results of such an analysis are included here. Finally, results of high speed balancing, critical for such a large flexible rotor are presented and discussed. This repair and rejuvenation work allowed salvaging the severely damaged rotor in approximately 5 months (compared to up to 2 years delivery for a new rotor) and at about one-fourth the rotor replacement cost.

The Dynamic Analysis of SFD-Sliding Bearing Flexible Rotor System Based on Optimization Design

2012 ◽  
Vol 159 ◽  
pp. 355-360
Author(s):  
Ji Yan Wang ◽  
Rong Chun Guo ◽  
Xu Fei Si
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Critical Speed ◽  
Structural Parameters ◽  
Rotor System ◽  
Flexible Rotor ◽  
Optimization Analysis ◽  
Sliding Bearing ◽  
Critical Speeds ◽  
Design Variables

The paper establishes the mechanical model of SFD-sliding bearing flexible rotor system, adopting Runge-Kutta method to solve nonlinear differential equation, thus acquiring the unbalanced response curve and then gaining the first two critical speeds of the system. Meanwhile, the paper analyzes the sensitivity of the system on the first two critical speeds towards structural parameters, offering design variables to optimization analysis. Based on sensitivity analysis, genetic algorithm is employed to give an optimization analysis on critical speed, which aims to remove critical speed from working speed as much as possible. The critical speed ameliorates after the optimization which supplies theoretical basis as well as theoretical analysis towards the dynamic stability of high-speed rotor system and provides reference for the design of such rotor system.

Stability of High Speed Rotors With Internal Friction

1974 ◽  
Vol 96 (3) ◽  
pp. 960-968 ◽  
Author(s):  
J. M. Vance ◽  
J. Lee
Keyword(s):  
Internal Friction ◽  
Differential Equations ◽  
Numerical Solution ◽  
High Speed ◽  
Critical Speed ◽  
Rotating Machinery ◽  
Rigid Foundation ◽  
Flexible Rotor ◽  
Mathematical Methods ◽  
The Stability

The problem of nonsynchronous whirl induced by internal friction is shown to be important when rotating machinery is designed for operation at supercritical speeds. Mathematical methods are used to determine the stability speed threshold of nonsyncronous whirl instability for an unbalanced flexible rotor on a rigid foundation. This threshold of instability is shown to be the same as the threshold for balanced rotors established by previous investigations. The location of the external damping (foundation or rotor) is shown to be important in determining stability when the foundation is made very rigid. The effect of shaft stiffness orthotropy on nonsynchronous whirl induced by internal friction is also investigated. Results from the stability analyses are verified by numerical solution of the differential equations. It is concluded that rotors can be safely operated up to speeds about eighty percent above the significant critical speed if the external damping is larger than the internal friction, and that shaft stiffness orthotropy has an insignificant effect on friction-induced whirl.

scholarly journals Progress on the Advanced Turbine Technology Applications Project (ATTAP), and Automotive Gas Turbine Outlook

1992 ◽  
Author(s):  
Philip J. Haley
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Turbine Rotor ◽  
Department Of Energy ◽  
General Motors ◽  
Heat Management ◽  
Static Structure ◽  
Durability Test ◽  
Refractory Fiber ◽  
Injection Molded

Of the four key technology areas attendant to the automotive gas turbine (ACT), structural ceramic components are the prime focus of the Department of Energy (DOE)-sponsored, NASA-managed ATTAP. The General Motors (GM) ATTAP team first focused on the ceramic gasifier turbine rotor, and in 1990 achieved full design temperature (2500°F TIT) at 100%N1 (gasifier speed). Four generations of axial-rotor design have led to such success, which also includes demonstrated resistance to foreign object impact; functionality after impact and minor damage; survivability in high-speed tip rub; and a 1000-hour durability demonstration. The ceramic gasifier turbine static structure, comprising scroll and vaneset (plus other support components), has also been successfully demonstrated at full (2500°F) design conditions, including successful completion of a 100-hour durability test of an all-ceramic gasifier stage. This major contractual milestone was completed during 1991. These successes represent fundamental technology progress, not only in the GM designs, but in the materials and processes implemented by the Kyocera Corporation, Norton/TRW Ceramics, and GTE Labs. Heat management (regenerator system and thermal insulation) and combustion are other key AGT technologies. Ceramic regenerator disk efforts with Corning focus on developing extrusion technology in concert with evaluation of four ceramic material systems, to provide a disk with the requisite geometry, strength, survivability, and cost characteristics. Insulation activities with Manville target developing a ceramic refractory fiber-based system, which is wet injection molded directly in-place, and has the required thermal, adhesion, durability, and erosion properties. During 1991 a turbine engine component was successfully injection molded with this system. Some ATTAP effort has been directed toward design of a prevaporizing/premixing combustor to meet the California 0.2 gm/mile NOx standard.

Eccentricity and Rotational Speed Effect on the Rotor-Bearing

2013 ◽  
Vol 274 ◽  
pp. 237-240
Author(s):  
Bing Dai ◽  
Guang Bin Yu ◽  
Jun Peng Shao ◽  
Long Huang
Keyword(s):  
Periodic Motion ◽  
High Speed ◽  
Element Model ◽  
Turbine Rotor ◽  
Radial Deformation ◽  
Force Model ◽  
Actual System ◽  
Non Linear ◽  
Rotor Bearing ◽  
Bearing System

Bearing dimensionless nonlinear oil film force model is deduced based on Capone theory of cylindrical bearings in this paper. Jeffcot rigid rotor-bearing system dynamic equations are built based on nonlinear dynamics, bifurcation, chaos theory. Eccentricity increases with the speed of the system by writing MATLAB codes. It appears the periodic motion, times of periodic motion and a series of non-linear kinetics. The system eccentricity increases with a series of emergence of non-linear dynamics when speed conditions is fixed, which is the actual system design’s basis. The finite element model of gas turbine rotor-bearing system is built by ANSYS software platform in this paper. The radial bearing deformation relationship are obtained by deformation theory of centrifugal force at high speed bearing radial deformation.

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