Inlet Guide Vanes (IGVs) are used to deliver a
defined preswirl for the following rotor and can be
used to adjust the stage’s aerodynamic
performance. Using Variable Inlet Guide Vanes
(VIGVs) the preswirl can be varied in a wide range
in order to control the compressor’s operating
point. Figure 1 shows a VIGV as applied in
multishaft compressors. These machines are used
for compression of gases in several industrial fields
like fertilizer industry, oil and gas or power
generation ([12], [13]). They provide a pressure
ratio up to 150 and in most applications they run
with a constant shaft speed. Hence, these
compressors are adjusted basically by VIGVs (see
[3]). Vanes with symmetric profiles are often found
as their stagger angle can be changed in both
positive and negative direction without preference
of one of the turning directions. Disadvantages of
symmetric VIGVs are high losses at relatively
small turning angles and eventually a high
sensitivity for stall occurrence ([5], [9]). In order to
reduce the losses and to optimize the blade
performance, it is essential to know details of the
flow on the vane (e.g. the presence of a laminar or
turbulent boundary layer, flow separation,
transition etc.). Experimental investigations with a
VIGV linear cascade have been conducted at the
Institute of Jet Propulsion at the Universität der
Bundeswehr München. The effects of varying
stagger angle and Reynolds number on the profile
losses are investigated and the detailed analysis is
supported by measurements inside the boundary
layers on the vane surface. For this reason a Preston
probe was used to determine the near wall flow
and to perform traverses along the boundary layer.
«Inlet Guide Vanes (IGVs) are used to deliver a
defined preswirl for the following rotor and can be
used to adjust the stage’s aerodynamic
performance. Using Variable Inlet Guide Vanes
(VIGVs) the preswirl can be varied in a wide range
in order to control the compressor’s operating
point. Figure 1 shows a VIGV as applied in
multishaft compressors. These machines are used
for compression of gases in several industrial fields
like fertilizer industry, oil and gas or power
genera...
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