Numerical simulations to assess the performance of scoop based lubrication devices for use in aero-engines
In civil aircraft aero engine bearing chambers it is sometimes difficult to feed oil to bearings using the traditional under-race or targeted jet approaches. In such situations one proposed solution is that of a scoop delivery system. Published experimental investigations into scoop performance show...
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| Format: | Thesis (University of Nottingham only) |
| Language: | English |
| Published: |
2019
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| Online Access: | https://eprints.nottingham.ac.uk/56685/ |
| Summary: | In civil aircraft aero engine bearing chambers it is sometimes difficult to feed oil to bearings using the traditional under-race or targeted jet approaches. In such situations one proposed solution is that of a scoop delivery system. Published experimental investigations into scoop performance show that scoop collection efficiency (the percentage of oil delivered by the scoop system to its destination compared to that supplied by the feed jet) is a function of many operational and geometric parameters. However even with high speed imaging it is impossible to experimentally determine in detail the factors that most contribute to reduction in capture efficiency and it is here particularly that a Computational Fluid Dynamics (CFD) investigation has value.
In the work of this thesis CFD investigations using ANSYS FLUENT are used to investigate the performance of scoop based lubrication devices. The computational domain, a 2D slice through the chosen scoop system, is discretized utilizing ANSYS Meshing. The Volume of fluid (VOF) model is used to model the multiphase flow of oil and air in the system and the RNG k-ε turbulence model is employed to account for the effects of turbulence. Comparison of numerical results with experimental results indicate good agreement. Results achieved from analytical modelling also support the results obtained from CFD and experiments. The effect of vortex shedding from the tip of scoops and different scoop geometries on the capture efficiency have also been investigated. A computationally efficient model for assessing the performance of scoops has been developed in this PhD. |
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