| 1. |
- Gezork, Tobias, et al.
(author)
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Unsteady blade force computation sensitivity in a transonic turbine to rotor tip gap, hub and shroud cavity model detail
- 2015
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In: Proceedings of the 14th International Symposium on Unsteady Aerodynamics, Aeroacoustics & Aeroelasticity of Turbomachines.
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Conference paper (peer-reviewed)abstract
- The influence of including geometric detailing features on blade forcing predicted by CFD calculations is investigated. Various features such as rotor tip gap, rotor tip shroud cavity with substantial leakage flow and large rotor upstream hub rim cavity are investigated. The test case is based on a single stage transonic test turbine rig in which the unsteady aerodynamics and blade forcing have previously been investigated numerically.Including the tip gap and the tip shroud leakage in the computational model resulted in an overall increase in unsteady forcing. The change in forcing is mainly due to a change in secondary flow structure, but also due to a change of the stage flow condition. Conversely, it is shown that including the hub cavity in the computational model, even without the presence of purge-flow, reduces the unsteady force. Lastly, even though there are changes in unsteady blade loading, the blade response amplitude is only changed marginally (maximum 7%) due to forcing variations alone.
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| 2. |
- Gutierrez, Mauricio, et al.
(author)
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Forced response analysis of a transonic turbine using a free interface component mode synthesis method
- 2015
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In: 11th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2015. - : European Conference on Turbomachinery (ETC).
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Conference paper (peer-reviewed)abstract
- Assessing forced response is crucial during the design phase of turbomachines. Since the analyses are computationally expensive and time-consuming when using full models, Reduced Order Models (ROM) are utilized to decrease the number of Degrees Of Freedom (DOF) and consequently analysis time and cost. The ROM used in the current analysis belongs to the component mode synthesis (CMS) method with a free-interface approach known as Craig-Chang. A transonic high pressure turbine is investigated featuring large ranges of disk and blade dominated modes depending in the Nodal Diameter (ND). The free-interface approach will be assessed in the disk and blade dominated regions with a detailed study of the frequencies and mode shapes. In addition, a forced response analysis within the blade dominated region is evaluated in the paper. Moreover, a study of the amount of modes required in the basis for the reduced order transformation matrix is presented.
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