A commercial Navier-Stokes flow solver has been employed for simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stato...A commercial Navier-Stokes flow solver has been employed for simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stator of a high pressure steam turbine. For comparison, we have studied the effects of bowed blades on the wakes of stator trailing edge and horse shoe vortex in the rotor. It was found that the position of wakes for bowed blades is shifted toward the blade suction side. Also, we have discussed and compared the entropy generation and energy loss caused by dissipation mechanism within the boundary layers on the hub and shroud; and temperature gradient in meridional plane.展开更多
In order to examine the fundamental characteristics of corner separation in a decelerating cascade flow,the experimental apparatus was made and separations around a NACA65 blade in a decelerating channel flow were exa...In order to examine the fundamental characteristics of corner separation in a decelerating cascade flow,the experimental apparatus was made and separations around a NACA65 blade in a decelerating channel flow were examined.Two-dimensional calculations show that the NACA65 cascade flow that has 45 deg.of turning,1.24 of solidity and 17 deg.of stagger angle is equivalent to the channel flow that has 14 deg.of stagger angle in terms of pitchwise blade force.Experimental investigation by five-hole probe shows that the accumulations of low energy fluid can be seen around the corner part and the overturning flow due to the secondary flow exists.And,as the periodicity of the blade wake in a pitchwise direction is comparably good,the wake of this channel flow is similar to the wake of the cascade flow for two pitch portion.PIV measurement results shows that a vortex pattern can be seen in the momentary streamline on the suction surface of the blade and in the averaged streamline on the perpendicular to both the suction surface and the endwall.展开更多
文摘A commercial Navier-Stokes flow solver has been employed for simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stator of a high pressure steam turbine. For comparison, we have studied the effects of bowed blades on the wakes of stator trailing edge and horse shoe vortex in the rotor. It was found that the position of wakes for bowed blades is shifted toward the blade suction side. Also, we have discussed and compared the entropy generation and energy loss caused by dissipation mechanism within the boundary layers on the hub and shroud; and temperature gradient in meridional plane.
文摘In order to examine the fundamental characteristics of corner separation in a decelerating cascade flow,the experimental apparatus was made and separations around a NACA65 blade in a decelerating channel flow were examined.Two-dimensional calculations show that the NACA65 cascade flow that has 45 deg.of turning,1.24 of solidity and 17 deg.of stagger angle is equivalent to the channel flow that has 14 deg.of stagger angle in terms of pitchwise blade force.Experimental investigation by five-hole probe shows that the accumulations of low energy fluid can be seen around the corner part and the overturning flow due to the secondary flow exists.And,as the periodicity of the blade wake in a pitchwise direction is comparably good,the wake of this channel flow is similar to the wake of the cascade flow for two pitch portion.PIV measurement results shows that a vortex pattern can be seen in the momentary streamline on the suction surface of the blade and in the averaged streamline on the perpendicular to both the suction surface and the endwall.
