CFD evaluation of a turbine rear structure with an integrated heat exchanger
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Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The expanding aviation industry is currently experiencing a substantial transition
in order to become more sustainable. A more environmentally friendly alternative
to traditional jet fuel is liquid hydrogen, an option that has been investigated by
GKN Aerospace among others. Employing liquid hydrogen imposes many engineer ing challenges, one of which is the design on the turbine rear structure part (TRS) of
the engine. This section of an aeroplane engine is of special interest to GKN as it is
one of their main products. As liquid hydrogen has to be kept at low temperatures
in order to remain in its liquid state, a state most suited for use in aircraft due to
the low energy density of gases, and as the air exiting an engine is typically very
hot this opens the possibility, if not necessity of heat exchange between the fluids.
A model of a heat exchanger that can be used for this purpose was constructed
by GKN and tested at Chalmers university of technology where the hydrogen was
replaced by heated water. A patent for the heat exchanger model had been filed but
not obtained during the thesis work which meant that the exact geometry of it was
omitted from the thesis.
In this thesis the tests at Chalmers were used in order to perform CFD simulations of
the turbine rear structure with an integrated heat exchanger. The results obtained
from the CFD were then validated by comparing turbulence models and boundary
condition specification methods after which the results were compared to the test
data. The validity of the used CFD model was confirmed using tests and reasoning
although the CFD model was shown to over predict the magnitude of separation
zones. The measured outlet temperature of the water was shown to be accurately
predicted by the CFD simulations. Additional simulations of a TRS without the heat
exchanger were also carried out to highlight the difference between using and not
using a heat exchanger. Finally the performance of the heat exchanger was assessed
by calculating its effectiveness for the different simulations which gave indications
for the optimal air flow through it.
Beskrivning
Ämne/nyckelord
Heat Exchanger, CFD, TRS, Liquid Hydrogen, Aeroplane Engine, GKN Aerospace, OGV, high BPR turbofan, Turbulence modelling