Multiharmonic Analysis of Nonlinear Whole Engine Dynamics With Bladed Disc-Casing Rubbing Contacts

Author(s):  
E. P. Petrov

A method has been developed for frequency domain analysis of steady state forced response in gas turbine engines in the presence of rubbing and snubbing contacts between bladed discs and casing and between other rotor and stator engine components. The multiharmonic contact interface elements have been derived for modelling the nonlinear contact interactions: (i) at bearings and (ii) bladed disc-casing rubbing contacts with using flexible models for rotor and stator structures. The elements allow for the asymmetry of the casing, the discrete blade contacts with casing, individual blade-casing gap values, nonlinear dependency of the contact forces on rotor-stator incursion and friction forces, intermittent contacts between blades and the casing. High accuracy and computational efficiency of the methods and models developed has been demonstrated on a set of test cases and on an example of analysis of a realistic gas turbine structure.

Author(s):  
Edward M. House

Four Textron Lycoming TF40B marine gas turbine engines are used to power the U.S. Navy’s Landing Craft Air Cushion (LCAC) vehicle. This is the first hovercraft of this configuration to be put in service for the Navy as a landing craft. The TF40B has experienced compressor blade pitting, carbon erosion of the first turbine blade and hot corrosion of the hot section. Many of these problems were reduced by changing the maintenance and operation of the LCAC. A Component Improvement Program (CIP) is currently investigating compressor and hot section coatings better suited for operation in a harsh marine environment. This program will also improve the performance of some engine components such as the bleed manifold and bearing seals.


1985 ◽  
Vol 107 (1) ◽  
pp. 205-211 ◽  
Author(s):  
J. H. Griffin ◽  
A. Sinha

This paper summarizes the results of an investigation to establish the impact of mistuning on the performance and design of blade-to-blade friction dampers of the type used to control the resonant response of turbine blades in gas turbine engines. In addition, it discusses the importance of friction slip force variations on the dynamic response of shrouded fan blades.


Author(s):  
Youry A. Nozhnitsky ◽  
Youlia A. Fedina ◽  
Anatoly D. Rekin ◽  
Nickolai I. Petrov

For years of time there have been conducted the investigations of gas-turbine engine parts made of carbon-carbon and ceramic materials. This paper presents mainly the results of works done to create engine components of ceramic materials. There are given the investigation results on development of equipment and methods intended for use in determining the characteristics of heat-resistant non-metallic materials under ultra high temperature conditions. The unique tooling is developed to be used for conducting mechanical tests in different conditions (vacuum, protective medium, air) at temperatures up to 2200°C. There are considered three possible fields of application of ceramic materials, that are, turbine (1), combustion chamber and other stator components operating at high temperatures (2), bearings (3). Different ceramic elements are designed and manufactured, their structural strength is investigated in the laboratory faculties and also as part of engine gas generators.


Author(s):  
Sanford Fleeter ◽  
Patrick B. Lawless

Abstract This paper is directed at providing the smart structure technology community an introduction to aircraft gas turbine engines issues that might be addressed, i.e. smart/active propulsion systems. Specifically, in gas turbine engines, smart structures can (1) influence performance, stability, noise and high cycle fatigue by providing airfoil aerodynamic control, (2) alleviate or avoid high cycle fatigue due to flutter and forced response by introducing damping intra structures, and (3) provide health monitoring. However, the benefits-to-cost ratio of the added complexity of incorporating smart materials into gas turbine engines must be large as smart materials and actuator/control systems are not a simple solution to complex problems. The prime selling point of smart structure technology to current state-of-the-art gas turbine engines may be adaptability to age, mission, and the environment.


Author(s):  
Michael P. Enright ◽  
R. Craig McClung ◽  
Luc Huyse

Rare anomalies may be introduced during the metallurgical or manufacturing processes that may lead to uncontained failures of aircraft gas turbine engines. The risk of fracture associated with these anomalies can be quantified using a probabilistic fracture mechanics approach. In this paper, a general probabilistic framework is presented for risk assessment of gas turbine engine components subjected to either inherent or induced material anomalies. A summary of efficient computational methods that are applicable to this problem is also provided.


Author(s):  
A. V. Soudarev ◽  
E. D. Vinogradov ◽  
Ju. I. Zakharov

The results of experimental elaboration of engineering approaches relating to environmental update of combustors for the GTK-10 10 MW, GTG-1500 1.5 MW and GT-100 100 MW gas turbine engines are presented. The combustor update was carried out by a technique of directed dosed air blow into the maximum temperature zone with in the fire space. The advantages of the technique are as follows: • feasibility of reduction of Nox concentration in waste gases to 50 ppm; • simplicity and adaptability to manufacture of the structure; • no need in changing the design of the engine components and systems; • short-time outage of the unit at update.


2005 ◽  
Vol 127 (4) ◽  
pp. 806-815 ◽  
Author(s):  
J. U. Schlüter ◽  
X. Wu ◽  
S. Kim ◽  
S. Shankaran ◽  
J. J. Alonso ◽  
...  

Full-scale numerical prediction of the aerothermal flow in gas turbine engines are currently limited by high computational costs. The approach presented here intends the use of different specialized flow solvers based on the Reynolds-averaged Navier-Stokes equations as well as large-eddy simulations for different parts of the flow domain, running simultaneously and exchanging information at the interfaces. This study documents the development of the interface and proves its accuracy and efficiency with simple test cases. Furthermore, its application to a turbomachinery application is demonstrated.


Author(s):  
J. R. Palmer ◽  
Yong-Gen Gu

This paper presents a computer model called ‘TURBOTEST’ which is applicable both to analysis of gas turbine engine rig tests and to simulation of engine steady-state performance. As with the earlier ‘TURBOFLEXI’ model a wide range of gas turbine engines can be simulated, using any kind of hydrocarbon fuel, and allowing for chemical dissociation of the gas, and for the effect of air humidity. In addition, however, for the particular requirements of rig test analysis, the following new features have been developed and incorporate:- (a) It can carry out rig test analysis for a wide range of gas turbine engines if all the necessary test data are presented. (b) If the test data is incomplete, a computer simulation of the engine can be used to complete the analysis. (c) Performance deterioration of engine components can be detected by comparing the results of a test analysis and of a parallel simulation using stored characteristics of engine components in the “as new” condition. The program has been tested on simulated test data generated by engine models such as a turbojet and a turbofan. The results show it has close and repeatable agreement with design values. Further tests of the model have been carried out by applying it to the actual engine rig test data.


Author(s):  
A. F. McLean

This paper reviews the limitations today’s superalloys exercise on the realization of the potential of the gas turbine engine. Ceramic materials are suggested as a means of achieving lower cost and higher turbine inlet temperature in small gas turbine engines. The paper serves to introduce ceramic materials and processing techniques and identifies silicon nitride, silicon carbide and lithium-alumina-silicate as promising materials for high temperature turbine engine components.


Author(s):  
N. Sourial

Today’s high technology gas turbine engines incorporate the world’s most exotic alloys and are built to some of the most precise dimensional tolerances encountered in any industry. The constant drive for increased performance while substantially reducing fuel consumption and weight has pushed engine components and their designers to limits never before realized. To achieve these limits new methods and materials have evolved; not exclusively in the production of the engines but also in the repair and maintenance of them. The typical problems encountered in repair and maintenance are numerous and varied as are their solutions. This paper, however, will concentrate on one in particular and that is the typical damage encountered on a first stage power turbine vane ring and the technology employed to repair such damage. The vane ring was chosen because it is representative of a common problem encountered by all gas turbine engine manufacturers and simultaneously involves some of the most up to date repair techniques to restore it.


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