At the Large Scale Turbine Rig (LSTR) at Technische
Universiẗat Darmstadt the aerothermal interaction of combustor
exit flow conditions on the subsequent turbine stage is
examined. The rig resembles a high pressure turbine and is
scaled to low Mach numbers. A baseline configuration with
axial inflow and a swirling inflow representative for a lean
combustor is modeled by swirl generators, whose clocking
position towards the NGV leading edge can be varied. A
staggered double-row of cylindrical film cooling holes on the
endwall is examined.
The effect of swirling inflow on heat transfer and film
cooling effectiveness is studied, while the coolant mass flux
rate is varied. Nusselt numbers are calculated using infrared
thermography and the auxiliary wall method. Boundary
layer, turbulence and five-hole probe measurements as
well as numerical simulations complement the examination.
The results for swirling inflow show a decrease of film
cooling effectiveness of up to 40 % and an increase of Nusselt
numbers of 10-25% in comparison to the baseline case
for low coolant mass flux rates. For higher coolant injection,
the heat transfer is on a similar level as the baseline.
The differences vary depending on the clocking position. The
turbulence intensity is increased to 30 % for swirling inflow.