Entropy and vorticity wave generation in realistic gas turbine combustors
| Autor: | Nedunchezhian Swaminathan, Ivan Langella, Ann P. Dowling, Bernhard Semlitsch, Tom Hynes |
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| Přispěvatelé: | Semlitsch, Bernhard [0000-0001-7715-863X], Swaminathan, Swami [0000-0003-3338-0698], Apollo - University of Cambridge Repository |
| Rok vydání: | 2019 |
| Předmět: |
Physics
Gas turbines 020301 aerospace & aeronautics Indirect Combustion Noise Mechanical Engineering Aerospace Engineering Combustion 02 engineering and technology Mechanics Vorticity Fuel injection 7. Clean energy 01 natural sciences Turbine Compressible flow 010305 fluids & plasmas Unsteady flow Fuel Technology 0203 mechanical engineering Space and Planetary Science 0103 physical sciences Combustor Large eddy simulation |
| Popis: | Understanding the nature of the unsteady flow at the combustor exit is required to accurately simulate time dependent phenomena in the turbine entry, such as indirect noise generation. Using Large Eddy Simulations of the combustion process in a realistic geometry, we analyse the flow at its exit. Two realistic, near-ground certification operating conditions are considered. Different mechanisms for large-scale flow and thermal structure generation are described, which are ejected into the turbine. Modal decomposition methods are used to extract the spatial and temporal scales at the turbine entry. We find that, depending on the operating condition, the entropy waves convect as elongated streaks in the core of the combustor annulus or the proximity of the walls. The dominant unsteady character of the fluctuations exhibits different spectral properties, i.e. low-frequency in the core and high-frequency towards walls. At the combustor exit, the vortical field is dominated by the swirl in the air inlet, which is found to have little influence on the entropy perturbations. Further, the importance of considering the interaction of multiple fuel injectors and combustion zones in an annular combustor is investigated. It is shown that pulsating circumferential vorticity modes can occur in multi-sector annular combustors but these, however, do not affect the entropy wave distribution. |
| Databáze: | OpenAIRE |
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