The validation and coupling of computational fluid dynamics and finite element codes for solving 'industrial problems'
A modern gas turbine must be designed quicker, be more reliable, produce less
emissions than its predecessors and yet the engine manufacturer must still make a
profit. In order to sell their engines to the airlines, the manufacturer must show that
their engines meet strict safety and reliability requirements. The creation of finite
element models used for predicting temperatures and displacements of the engine
component's is part of this design cycle.
This thesis addresses the use of computational fluid dynamics (CFD) as a tool that
can help in the prediction of iiietal temperatures for use with "industrial" problems
and the associated requirements of accuracy and time-scales. The definition of 'industrial"
accuracy and time-scales in this thesis is the accuracy required to enhance
the modelling capability of a thermal engineer in design time-scales.
A method is developed for using a commercial CFD code. FLUENT, for predicting
flow and heat transfer. The code has been validated against several benchmark
test cases and has shown good predictive capability and mesh independence for flow
and heat transfer in the cavity between a rotating and stationary disc with and
without through-flow. For cavities between co-rotating discs with radial througliflow,
the predictions are acceptable, but some sensitivity of the heat transfer results
to mesh spacing has been identified. The code has also been validated against some
"industrial" test cases where experimental data has been available. The effects of
buoyancy in the centrifugal force field are discussed and are related to a buoyancy
The next part of the thesis develops a method of solving the heat transfer problem
by coupling a finite element code, SC03, with FLUENT. The ideas are developed on
two simple test cases and the problems of what information is to be passed across
the coupling boundary and convergence issues are discussed. The results show that
passing heat transfer coefficients and local air temperatures achieves the best convergence. The coupled method is their tested against two 'industrial problems. It
is concluded that the method has considerable potential for use in design although
some difficulties in applying the method are identified. Although not demonstrated,
the method developed is not specific to SC03 or FLUENT and ally heat traiisfer/
CFD codes could be used.