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Investigation of Premixed V-shaped Flame Response to Acoustic Oscillations

Nabatian, Negar | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40065 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Farshchi, Mohammad
  7. Abstract:
  8. Low emissions combustion V-flame combustors are exceptionally prone to combustion instabilities. These systems for land based gas turbines rely on a premixed or partially premixed combustion process. As V-flames do not anchored on the lip of combustor, an experimental study of the transfer function of these flames shows that they are more sensitive to fuel oscillations and in the range of frequencies, they behave like an amplifier. This paper presents an experimental study of the transfer function of a ducted, laminar, premixed V and M-flames. V-flame, laminar, propane/air premixed flame stabilised at the rim of the burner. The limit of M and V-flame are identified without excitation, then The flame is excited by incident acoustic waves generated by a loud speaker, placed upstream over a range of forcing frequencies. The fluctuations of heat release due to corrugation of the flame by the acoustic wave is measured using CCD camera, while the flow pressure fluctuation is determined by considering microphone. In this work by using theoretical model for V-flame, dominant parameters controlling the flame behavior are identified. Then by simulating in MATLAB image processing amplitude, phase are obtained. Also, deformation in flame shape and intensity of flame are acheived in one cycle of oscillation. Due to the results, It is shown that the multidimensionality of the acoustic field, the response of the flame to flow perturbations, and the production of vorticity all play important roles in these interactions. By using Transform Function instability conditions of combustor could be predicted. Investigation of flame behavior in one cycle identified in which phase, the fluctions of heat release due to velocity oscillations is maximum and also shows how nonlinear parameters effect in flame response.
  9. Keywords:
  10. Transfer Function ; Premixed Flame ; M-Flame ; V-Flame

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