Title page for ETD etd-10232000-10320002

Type of Document Master's Thesis
Author Liljenberg, Scott Alan
Author's Email Address liljenbe@vt.edu
URN etd-10232000-10320002
Title Modeling and Stability Analysis of Thermoacoustic Instabilities in Gas Turbine Combustor Sections
Degree Master of Engineering
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Saunders, William R. Committee Chair
Vandsburger, Uri Committee Co-Chair
West, Robert L. Jr. Committee Member
  • Combustion
  • Stability
  • Linear Systems
  • Acoustics
  • Thermoacoustic Instabilities
  • Time Delay
Date of Defense 2000-10-05
Availability unrestricted

In order to predict the linear stability of combustion systems in industrial-scale gas turbines, a stability analysis was completed using models generated for each of the major dynamic components. Changes in the combustion process of gas turbines to reduce emissions has resulted in large amplitude pressure oscillations associated with a coupling between the natural acoustic modes of the combustor and the unsteady heat release from the flame. Detailed models of the acoustics and the heat release processes were created and assembled, with a time delay element and the appropriate scaling, into a system block diagram to investigate the stability of the system using linear system theory. Wherever possible the analytical models were validated with experimental data. The main goal of this work was to create a design methodology which could be used by industry to predict where instabilities were likely to occur during the design phase. Results show that the system based stability analysis can predict some of the instability frequencies seen in the experimental data, but more refined models are needed to predict every instability. Future work will involve designing experiments to validate and refine the dynamic models already developed.

  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  Chap1.pdf 139.21 Kb 00:00:38 00:00:19 00:00:17 00:00:08 < 00:00:01
  Chap2.pdf 18.23 Kb 00:00:05 00:00:02 00:00:02 00:00:01 < 00:00:01
  Chap3.pdf 1.48 Mb 00:06:50 00:03:31 00:03:04 00:01:32 00:00:07
  Chap4.pdf 623.12 Kb 00:02:53 00:01:29 00:01:17 00:00:38 00:00:03
  Chap5.pdf 128.68 Kb 00:00:35 00:00:18 00:00:16 00:00:08 < 00:00:01
  Chap6.pdf 309.12 Kb 00:01:25 00:00:44 00:00:38 00:00:19 00:00:01
  Intro.pdf 31.54 Kb 00:00:08 00:00:04 00:00:03 00:00:01 < 00:00:01
  References.pdf 11.56 Kb 00:00:03 00:00:01 00:00:01 < 00:00:01 < 00:00:01

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