Authors
Abstract
The accuracy of computer codes for turbo-machinery turbulent flow field
calculations relies strongly on the type and behavior of the turbulence model used
in the computations. Analysis of different Reynolds Average Navier-Stokes
Equation (RANS) based turbulence models was applied to predict the flow field in
the linear first stage gas turbine cascade blade. The experimental investigation is
also introduced to validate the accuracy of turbulence models. This was done by
using five linear cascade blades tested in an open jet type low-speed subsonic wind
tunnel. The static pressure distribution was measured at the midspan of cascade
middle blade by using static pressure taps. The numerical results obtained from
different turbulence model simulations is individually reviewed for the correctness
of its predictions and compared with the experimental data in terms of integrated
flow parameters, such as static pressure coefficient distribution on both blade sides.
The results show that RNG k-e turbulence model gave the best prediction of
pressure distribution when compared with the experimental data. Prediction of
standard k-ε and k-ω turbulence models fail to predict accurately the flow field
parameters in cascade passage. Prediction of (k-ε) turbulence model overestimate
the turbulence kinetic energy values, especially in the regions of high velocity at
blade suction side, also not accurately predict the flow separation on the blade
suction side.
Keywords
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