Abstract
Highly loaded nozzle blades of steam turbines are developed. The pitch-chord ratio of these nozzles increases by 14% compared to one of conventional nozzles. And the increase of the stage efficiency is about 0.35% at the design point. This reason is that the strong adverse pressure gradient along blade suction surface is avoided in spite of the increase of blade loading, because the blade loading is equally distributed to the whole blade and the curvature of suction surface are optimized. In the first step of development, the nozzles are designed by the aid of computational fluid dynamics technique. In the next step, the aerofoil performances are tested by the use of linear cascade test facility. In the final step, the increases of stage efficiency are assured by the air turbine test results.
