抄録
This paper describes the unsteady force acting on steam turbine
buckets which is induced by a potential field and a wake. A new
method is proposed that can separate a potential field interaction
and a wake interaction from the unsteady viscous flow computation.
The new method does two computations for one model to get
inviscid and viscous flow solutions. Then the quantitative effects of
the factors that influence the unsteady force acting on the turbine
buckets are clarified.
The nozzle-bucket axial gap length is adopted for the factor to be
studied and the proposed method is used to calculate the unsteady
force of the bucket sections with different bucket heights in the
same stage. The simple relationships between the nozzle-bucket
axial gap length and the unsteady force are found to give easy and
reliable prediction of the force.
