University of Cambridge
The Impact of Combustor Turbulence on Loss Mechanisms in the High Pressure Turbine
Abstract
dc:description.abstractA blade row which is located downstream of a combustor has an extremely high turbulence intensity at inlet, typically above 10%. The peak turbulent length scale is also high, at around 20% of the chord of the downstream blade row. In a combustor, the turbulence is created by impinging jets in cross flow. This may result in the turbulence being anisotropic in nature. The aim of this thesis is to investigate the effect of combustor turbulence on the loss mechanisms which occur in a turbine blade row. The thesis has a number of important findings. The combustor turbulence is characterised and is shown to be isotropic in nature. It shows that, when no pressure gradient is present, combustor turbulence increases the loss of a turbulent boundary layer by 22%. The mechanism responsible for this change is shown to be a deep penetration of the turbulence into the boundary layer. It shows that the presence of combustor turbulence increases profile loss and endwall loss in the turbine cascade studied by 37% and 38%, respectively. The presence of combustor turbulence also introduces a freestream loss resulting in the total loss of the turbine cascade rising by 47%. When these loss mechanisms were applied to the vane, of an engine-representative high pressure turbine stage, it was found to result in a 1.3% reduction in stage efficiency.
Degree
thesis:*- Level dc:type.qualificationlevel
- Doctoral
- Grantor dc:publisher.institution
- University of Cambridge
- Year dc:date.issued
- 2019
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Folk, Maria
- Advisor dc:contributor.advisor
-
- Miller, Rob
Subjects
dc:subject × 6Rights
dc:rightsIdentifiers
dc:identifier.*- DOI dc:identifier.doi
- https://doi.org/10.17863/CAM.52404
- OAI identifier oai:identifier
- oai:www.repository.cam.ac.uk:1810/305319