Title page for ETD etd-11282001-190912


Type of Document Dissertation
Author Huang, Xinming
Author's Email Address xihuang2@vt.edu
URN etd-11282001-190912
Title Development of Reduced-Order Flame Models for Prediction of Combustion Instability
Degree PhD
Department Electrical and Computer Engineering
Advisory Committee
Advisor Name Title
Baumann, William T. Committee Chair
Kachroo, Pushkin Committee Member
Saunders, William R. Committee Member
Vandsburger, Uri Committee Member
VanLandingham, Hugh F. Committee Member
Keywords
  • limit cycle
  • combustion instability
  • reduced-order model
  • describing function
Date of Defense 2001-09-21
Availability unrestricted
Abstract
Lean-premixed combustion has the advantage of low emissions for modern gas turbines, but it is susceptible to thermoacoustic instabilities, which can result in large amplitude pressure oscillations in the combustion chamber. The thermoacoustic limit cycle is generated by the unsteady heat release dynamics coupled to the combustor acoustics. In this dissertation, we focused on reduced-order modeling of the dynamics of a laminar premixed flame. From first principles of combustion dynamics, a physically-based, reduced-order, nonlinear model was developed based on the proper orthogonal decomposition technique and generalized Galerkin method. In addition, the describing function for the flame was measured experimentally and used to identify an empirical nonlinear flame model. Furthermore, a linear acoustic model was developed and identified for the Rijke tube experiment. Closed-loop thermoacoustic modeling using the first principles flame model coupled to the linear acoustics successfully reproduced the linear instability and predicted the thermoacoustic limit cycle amplitude. With the measured experimental flame data and the modeled linear acoustics, the describing function technique was applied for limit cycle analysis. The thermoacoustic limit cycle amplitude was predicted with reasonable accuracy, and the closed-loop model also predicted the performance for a phase shift controller. Some problems found in the predictions for high heat release cases were documented.
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 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  Appendix.pdf 726.33 Kb 00:03:21 00:01:43 00:01:30 00:00:45 00:00:03
  Bibliography.pdf 128.18 Kb 00:00:35 00:00:18 00:00:16 00:00:08 < 00:00:01
  Chapter1.pdf 149.08 Kb 00:00:41 00:00:21 00:00:18 00:00:09 < 00:00:01
  Chapter2.pdf 245.14 Kb 00:01:08 00:00:35 00:00:30 00:00:15 00:00:01
  Chapter3.pdf 853.46 Kb 00:03:57 00:02:01 00:01:46 00:00:53 00:00:04
  Chapter4.pdf 594.54 Kb 00:02:45 00:01:24 00:01:14 00:00:37 00:00:03
  Chapter5.pdf 349.02 Kb 00:01:36 00:00:49 00:00:43 00:00:21 00:00:01
  Chapter6.pdf 506.66 Kb 00:02:20 00:01:12 00:01:03 00:00:31 00:00:02
  Chapter7.pdf 110.45 Kb 00:00:30 00:00:15 00:00:13 00:00:06 < 00:00:01
  Frontmatter.pdf 279.94 Kb 00:01:17 00:00:39 00:00:34 00:00:17 00:00:01

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