The evolution of the secondary flow field in cases of axial turbine bladings is examined in the present work.
Our secondary flow calculation method is successfully used, in an improved form including the complete meridional vorticity transport equation, to predict common viscous flow phenomena in axial turbines, such as high turning of the flow direction and jet-like velocity profiles.
The method used, although close to the parabolized Navier-Stokes approach, preserve several integral approximations thus minimizing the computer time required as compared to equivalent differential approaches. Our method provide fast and reliable tools for industrial applications with results comparable to those obtained by the differential solutions of the Navier-Stokes equations.
Several test cases, covering a wide deflection angle and acceleration ratio range, are analyzed. The results, concerning the secondary flow field, are very encouraging and Justify the choice of using approximate methods to estimate viscous phenomena in axial turbines.