Combustion instability represents a significant problem in the application of low emission lean premixed combustion for gas turbines and has become one of the primary concerns in modern gas turbine industry. Effusion cooling has become common practice in gas turbine combustors and when calibrated, perforated combustor liners are able to attenuate combustion instability within a wide frequency range. However, the acoustic attenuation effect of perforated liner absorbers varies with a considerable number of flow and geometry influencing factors. The traditional approach of designing perforated combustor liners relies heavily on expensive and lengthy trial-and-error experimental practice. Computational fluid dynamics (CFD), especially large eddy simulation (LES) method has gained recognition as a viable tool for the simulation of unsteady flows and the phenomenon of combustion instability in gas turbine combustors. However, detailed resolution of the many small scale features, such as effusion cooling holes, is computationally very expensive and restricts the routine simulation of detailed engine geometries. In this thesis, a novel homogenous porous media model is proposed for the simulation of acoustic attenuation effect of gas turbine perforated liners. The model is validated against a number of well-acknowledged experiments and is shown to be able to predict acoustic attenuation properties of gas turbine liners both in the linear and non-linear absorption regimes and also the effect of bias flow, grazing flow and the temperature of flow on the acoustic properties of the liners. The model is applied to a large eddy simulation of a lab-scale premixed combustor "PRECCINSTA" and is demonstrated to successfully represent noise attenuation effects of perforated liner absorbers in both cold flow and reacting flow conditions. This model is able to provide a significant reduction in the overall computational time in comparison to directly resolved geometries, and can be applied as such a viable option for routine engineering simulation of perforated combustor liners.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:733013 |
| Date | January 2017 |
| Creators | Wang, Jianguo |
| Contributors | Rubini, Philip A. |
| Publisher | University of Hull |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hydra.hull.ac.uk/resources/hull:16076 |
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