A SIMPLE PROCEDURE TO REDUCE SECONDARY FLOW EFFECT IN TURBINE NOZZLE GUIDE VANES

摘要

Secondary flow contributes about one-third of the total loss in turbine nozzle. Although secondary flow characteristics are well understood, it is still a challenge to mitigate the secondary flow effect. Several methods have been proposed to reduce secondary flow loss in turbine blade rows. They include: blade 3D stacking, blade 3D design, and end wall contouring, either axisymmetric and non-axisymmetric. The latter approach produces fully 3D end wall geometry, in contrast to the conventional axisymmetric shape. Several authors have applied elaborated procedure to adjust the end wall geometry of turbine blade rows. In this paper, we present a simple method to modify the hub wall of a turbine nozzle guide vane row with a single function. This function requires 2 geometry parameters which are established by CFD. The numerical results for a high work turbine nozzle guide vane show that a reduction in secondary kinetic energy is possible.