TY - THES ID - 146390487 TI - Final work : Assessment of throughflow closure models for a modern axial compressor AU - Ruis, Bart AU - Terrapon, Vincent AU - Hillewaert, Koen AU - Budo, Arnaud PY - 2021 PB - Liège Université de Liège (ULiège) DB - UniCat KW - Throughflow method KW - Navier-Stokes based KW - Computational Fluid Dynamics KW - Time-marching KW - Profile loss KW - Deviation angle KW - Tip leakage flows KW - Ingénierie, informatique & technologie > Ingénierie aérospatiale UR - https://www.unicat.be/uniCat?func=search&query=sysid:146390487 AB - This master’s thesis is dedicated to the assessment of various closure models for Navier-
Stokes-based throughflow modelling. This is done in the context of a high-subsonic flow
compressor with highly loaded blades of three-dimensional design.
The averaging cascade of Adamczyk is employed to identify the unclosed terms in the
Navier-Stokes throughflow equations. The terms of major importance are identified based
on the literature and related to the physical flow features that they represent. Empirical
models for the blade profile loss, deviation angle, tip leakage loss, and end-wall boundary
layer are then selected from the literature.
The accuracy of these models is assessed through three approaches. First, two-dimensional
blade-to-blade computational fluid dynamics simulations of a stator blade row are performed
to analyse various empirical models for profile loss and deviation. This analysis
confirms that compressibility effects need to be accounted for at elevated Mach number,
particularly for prediction at off-design incidence angle. The profile loss model of König is
shown to be more accurate than the model of Lieblein in this respect. The deviation angle
models of Carter, Lieblein and Wu Dong-Run are shown to give reasonable predictions at
design incidence angle.
The second approach is to feed the empirical models with circumferentially averaged
results of three-dimensional computational fluid dynamics simulations of the entire compressor.
This reveals the deficiency of König’s model for incidence angles much smaller
than the predicted minimum loss incidence angle. Two tip leakage models of Lakshminarayana
are also assessed in this context.
In the third approach, the empirical models are implemented in a Navier-Stokes throughflow
model. The resulting radial distributions of loss and deviation are analysed for all
blade rows at nominal operating conditions. Finally, the results are discussed in terms of
isentropic efficiency, pressure ratio, and total temperature ratio of the entire compressor
operating at off-design conditions. ER -