Fundamental Studies of Turbulent Boundary Layers with Injection or Suction through Porous Wall : 4th Report, Application of Fundamental Theoretical Analysis to Cascaded Blades with Injection or Suction and Cascade Tests

Abstract

In the present paper, the authors intend to discuss the applicability of the analytical method for a turbulent boundary layer having pressure gradients with injection or suction treated in the previous papers to the boundary layer on the cascaded blade surfaces with injection or suction all over them and to investigate the influence of the injection or the suction on the cascaded blade characteristics by the cascade tests. The following main results are obtained: (1) The analytical method for a turbulent boundary layer having pressure gradients with injection or suction treated in the previous papers is applicable to the boundary layer on the blade surfaces with injection or suction all over them. (2) Judging from the total pressure loss coefficient, though the optimum injection ratio must be determined after due consideration of the cooling characteristics of the blade, m the available injection ration in the fluid dynamic characteristics if ν₀/u₀≦0.004. And the effect of the suction all over the blade surfaces is found little for a high performance cascade (such as NACA A₃K₇).