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Title: Friction damping of flutter in gas turbine engines

This thesis investigates the feasibility of using friction dampers to control flutter in gas turbine engine rotor stages. First, the stabilizing effects of blade-to-ground dampers were studied on the basis of a single degree of freedom model of an isolated blade. To simulate aerodynamic instability, the viscous damping associated with each blade was taken to be negative. The following issues were addressed: the range of initial conditions over which the response is stable; the maximum negative damping that can be stabilized; the effect of external excitation; and the determination of optimum damper parameters. Secondly, the physical concepts and mathematical techniques required to analyze and understand the effects of friction dampers on aerodynamically unstable rotor stages were developed. A lumped parameter model was chosen for the rotor stage and the viscous damping associated with each blade is again taken to be negative. Results for 3, 4, and 5 bladed disks are discussed. Lastly, the influence of friction on the torsional blade flutter is examined, using Whitehead's model of incompressible fluid flow. On the basis of the results for 3, 6, 9, and 12 bladed disks, the use of friction dampers in controlling flutter appears promising.
Authors:
Publication Date:
OSTI Identifier:
6360947
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Publisher:
Carnegie-Mellon Univ.,Pittsburgh, PA, USA
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; GAS TURBINE ENGINES; AERODYNAMICS; ROTORS; MECHANICAL VIBRATIONS; DAMPING; TURBINE BLADES; CALCULATION METHODS; FRICTION; SIMULATION; ENGINES; FLUID MECHANICS; HEAT ENGINES; INTERNAL COMBUSTION ENGINES; MECHANICS 421000* -- Engineering-- Combustion Systems