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Development of a Thermoacoustic Model for Evaluating Passive Damping Strategies

  • Author(s): Rehman, Syed
  • Eldredge, Jeff D.
  • et al.
Abstract

Lean premixed prevaporized (LPP) gas turbine generators have become popular in energy conversion applications to meet strict emission requirements. Because the combustion process is very lean, combustion instabilities due to acoustic perturbations are more likely to occur than in a less lean fuel combustion process. Current design of damping strategies for mitigating these instabilities is often based on empirical trial and error, which precludes the possibility of determining an optimal configuration. A combustion system whose elements consist of flames, passive dampers, and ducts must be optimized to reduce or completely eliminate combustion instabilities. Hence, a modular simulation tool is developed to examine the interaction of plane acoustic waves with typical combustion system elements. The simulation tool represents these interactions in the form of transfer matrices, which can be modularly arranged for exploring a variety of configurations. In this work, a heuristic gain-delay flame model is represented as a transfer matrix, which can be used to test damping devices. Similarly, transfer matrices representing a Helmholtz resonator and a perforated liner with bias flow are developed, and preliminary results are obtained.

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