Abstract
A hybrid computational method using fluid dynamics has been proposed and developed for the blade design of steam turbines. It is composed of three main block: the quasi 3-dimensional through-flow calculation block, the fully 3-dimensional flow calculation block, and the mixing plane block. The hybrid computational method was applied to a 4-stage low-pressure steam turbine, where the rotating blade of the second stage was simulated in a fully 3-dimensional shape. The error in the steam mass flow rate across the mixing plane was confirmed to be sufficiently small, less than 0.5%. Primary design parameters such as the degree of reaction, Mach number and wetness mass fraction distributions were confirmed to be in good agreement with parameters for the fully 3-dimensional calculation of single turbine stage. In addition, the calculation time for four turbine stages was reduced by 40% as compared to the fully 3-dimensional calculation for single turbine stage. The developed hybrid method was judged as useful in the blade design of steam turbines.
