A Full Navier-Stokes Analysis of Flow and Heat Transfer in Steady Two-Dimensional Transonic Cascades
Fluid flow and heat transfer in a turbine blade row were investigated numerically using the two-dimensional, steady-state Navier-Stokes equations and the energy equation with dissipation. The finite-volume integration approach was employed to discretize the fully elliptic governing equations. A non-staggered grid system in the boundary-fitted coordinates was used and the compressible version of the SIMPLE was employed to solve extra equations. An ‘O-C-H’ type grid system was applied owing to its advantages of easily treating the blunt trailing edge and of producing less skewness in the boundary layer region. For an accurate prediction of the heat transfer coefficient at the turbine blade, the first numerical node from the wall was placed at y+∼3 so that it was embedded inside the viscous sublayer. The influence of the turbulence was analyzed with a new free-stream turbulence model which accounts for the free-stream turbulence and flow acceleration. Also the laminar-turbulent transition model was improved. Computations were performed for the low solidity Allison C3X turbine cascade. Present results showed good agreement with available experimental data in terms of the surface pressure and the heat transfer coefficient. Especially much improved distribution of the heat transfer coefficient was obtained in the vicinity of the leading and trailing edges. For practical purposes, the aerodynamic performance and the behavior of the heat transfer coefficient were analyzed by varying the inflow angle.