Influence of tip shroud cavity detailing on turbine blade forcing calculations
2014 (English)In: ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, ASME Press, 2014, Vol. 7B, V07BT35A021- p.Conference paper (Refereed)
Forced response in turbomachinery refers to the vibration of a component due to an excitation originating from another component. Obstacles, such as struts and blade rows in the upstream and downstream flow path of a turbomachine engine lead to engine order (EO) excitations. To be able to predict the severity of these excitations, both aerodynamic and structural calculations are performed. There is a risk of critical high cycle fatigue (HCF) failure when the force acts at a resonance frequency. Customarily, forcing calculations exclude detailing features, such as leakage flows. The current investigation uses a two stage subsonic model steam turbine configuration with shrouded rotor blades to demonstrate the influence of neglecting flow through seal cavities for blade forcing predictions. Upstream and downstream vanes are the excitation sources on the rotor blade. Calculation results are compared for a configuration including and excluding the tip shroud cavity. Computed data is compared to available pressure data from tests in the model turbine. The investigation shows for the first blade passing excitation at design point that the axial and circumferential rotor forcing change by +22%, respectively +4% when including the tip shroud cavity for the investigated configuration. The change in forcing arises from the interaction of the leakage flow with the main stream flow. For highly loaded designs this can be of importance if there is a critical excitation.
Place, publisher, year, edition, pages
ASME Press, 2014. Vol. 7B, V07BT35A021- p.
Engines, Excited states, Fatigue of materials, Leakage (fluid), Steam turbines, Stream flow, Turbomachine blades, Calculation results, Critical excitation, Downstream flow, Excitation sources, Forced response, High cycle fatigue, Resonance frequencies, Structural calculations
IdentifiersURN: urn:nbn:se:kth:diva-160680DOI: 10.1115/GT2014-26724ISI: 000362240200079ScopusID: 2-s2.0-84922237083ISBN: 9780791845776OAI: oai:DiVA.org:kth-160680DiVA: diva2:790989
ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, GT 2014, Dusseldorf, Germany, 16 June 2014 through 20 June 2014
FunderSwedish Energy Agency
QC 201502262015-02-262015-02-262015-10-28Bibliographically approved