Numerical simulation of heat transfer around film-cooled
gas
turbine blades
G. Medic and P.A. Durbin
Three-dimensional numerical simulation of film-cooling phenomena is becoming a part
of the complex procedure of gas turbine blade design and is slowly replacing more simplistic
two-dimensional
methods. However, the correct prediction of film-cooling and associated heat transfer is directly related
to the prediction of cross-flow jet mixing, which represents the major difficulty.
The majority of turbulence models fails for this configuration. Because of the presence of multiscale
flow
phenomena,
more fundamental approaches such as LES or DNS are computationally
impractical.
Another alternative is the improvement of existing (simpler) eddy-viscosity models in order to take into
account the effects present for this configuration and achieve more accurate predictions of film-cooling.
These results can then be used for optimal
blade design.
Here at FPCD, Stanford University, we
have conducted the preliminary analysis of an experimentally
documented film-cooling test case using different turbulence models, with the final goal of proposing
an improvement of existing models for this configuration.
The future step is to link the improved flow prediction code with the optimizitation procedure in order
to achieve an optimal shape or/and positioning of film holes.
Figure 1. Film cooling, pressure side cooling, jets penetrates into the mainstream.
Test case:
- VKI experiment (Camci & Arts, 1985),
- film-cooled gas turbine rotor blade,
- double row of staggered cooling holes,
- heat transfer along the suction side of the blade.
- transonic flow, inflow conditions:
Ma = 0.25, Re_c = 8.5e5, TU = 5 %,
T = 409.5 K, inflow angle = 30 deg,
- wall temperature: T_w = 298 K,
- variable coolant temperatures and blowing rates,
- heat transfer coefficient h comparisons,
Numerical computations:
References:
Downloads:
- STARCD user subroutine sorkep.f implementing Kato-Launder
k-epsilon model with two-layer formulation
- STARCD user subroutines sorkep.f and
vistur.f implementing Kato-Launder
k-epsilon model with two-layer formulation, as well as limitors
for the time scale T (effecting turbulent viscosity). When using limitors
for the time scale (through user defined turbulent viscosity
together with k-epsilon model),
SWITCH 12 in STARCD has to be set on. These files are
provided by
Jeong Min Seo
(FPCD, Stanford University).
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