Damage to the lipskin of an engine nacelle can have a significant impact on engine performance and safety, especially in combination with other sources of inlet flow distortion. While the degradation of performance in aircraft propulsion systems as a result of inlet distortion has been well-studied, the impact of lipskln damage upon inlet distortion levels is not well understood. Current practice can result in the grounding of aircraft in order to perform repairs if the damage exceeds the specified tolerance in size and the position on the lip, with these tolerances varying from aircraft to aircraft. If these tolerances are overly conservative, aircraft operating times may be adversely affected. The effect of lipskin damage upon the performance of the inlet of the CF34-3A engine has been investigated using the commercial Computational Fluid Dynamics Package ANSYS CFX in a nacelle model which included the fan. The fan was included in order to capture the interaction between the blades and the upstream distortion. The fan was found to have a stabilising effect upon the flow upstream of the fan, reducing the inlet distortion due to a redistribution of the flow. Other sources of inlet distortion have also been studied, with the effects of high angles of attack and crosswinds having been modelled in isolation, and combined with cases of lipskin damage. A typical take-off configuration was primarily used to assess the effect of the damage due to this being the most critical segment of the flight envelope. The resulting distortion levels have been compared to the engine manufacturers limits in order to assess the severity of the damage.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:557636 |
| Date | January 2011 |
| Creators | Kennedy, Stefan Andrew |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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