The compressor of a gas turbine engine is extremely vulnerable on upstream duct-
induced flow non-uniformities whether the duct is an engine intake or an
interconnecting duct. This is justified by its position being literally an
extension of the duct flow path, coupled to the fact that it operates under
adverse pressure gradients. In particular, this study focuses on performance
deviations between installed and uninstalled compressors. Test results acquired
from a test bed installation will differ from those recorded when the compressor
operates as an integral part of an engine. The upstream duct, whether an engine
intake or an inter-stage duct, will affect the flow-field pattern ingested into
the compressor. The case study presented here aims mostly at qualifying the
effect of boundary layer growth along the upstream duct wall on compressor
performance. Additionally, the compressor performance response on blade lean
angle variation is also addressed, with the aim of acquiring an understanding as
to how compressor blade lean angle changes interact with intake-induced flow
non-uniformities. Such studies are usually conducted as part of the preliminary
design phase. Consequently, experimental performance investigation is excluded
at this stage of development, and therefore, computer-aided simulation
techniques are used if not the only option for compressor performance
prediction. Given the fact that many such design parameters need to be assessed
under the time pressure exerted by the tight compressor development programme,
the compressor flow simulation technique needs to provide reliable results while
consuming the least possible computational time. Such a low computational time
compressor flow simulation method, among others, is the two-dimensional
streamline curvature (SLC) method, being also applied within the frame of
reference of the current study. The paper is introduced by a brief discussion on
SLC method. Then, a reference is made to the radial equilibrium equation, which
is the mathematical basis of SOCRATES, a turbomachinery flow simulation tool
that was used in this study. Subsequently, the influence of the upstream duct on
the compressor inlet radial flow distribution is being addressed, with the aim
of adjusting the compressor blade inlet lean angle, in order to minimize
compressor performance deterioration. The paper concludes with a discussion of
the results