Wj. Han et al., EFFECTS OF LEANING AND CURVING OF BLADES WITH HIGH TURNING ANGLES ON THE AERODYNAMIC CHARACTERISTICS OF TURBINE RECTANGULAR CASCADES, Journal of turbomachinery, 116(3), 1994, pp. 417-424
To understand the effects of the origination and development of centra
lized vortices on the aerodynamic characteristics of turbine rectangul
ar cascades with high turning angles, experiments with five-hole micro
spherical probes, accompanied by color helium bubble flow displays, we
re carried out. The measurement planes are arranged as three before, s
ix in, and one after the cascade. The experiments reveal that the orig
ination and development of horseshoe vortices and passage vortices as
well as the interaction of the latters almost dominate the whole flow
field of traditional linear cascades. Lean linear cascades favor the h
orseshoe vortices and passage vortices in the acute angle zone, and im
pede those in the obtuse angle zone. So it is a logical result to adop
t the negatively curved blades, whose pressure surfaces and both endwa
lls compose both obtuse angles, respectively, to improve the cascade a
erodynamic characteristics.