Patent ID: 8695345

Claim:
A calculation method for calculating an amount of moisture loss in a steam turbine generated when a steam condition in the steam turbine becomes wet steam, the moisture loss comprising loss elements including (1) supersaturation loss generated when steam expands so as to supersaturate at a blade cascade, (2) condensation loss generated when steam around water droplets condenses, (3) acceleration loss generated due to a difference in velocity between water droplets and steam, (4) braking loss generated when water droplets collide against suction sides of rotor blades, (5) capture loss generated when water droplets collide against surfaces of stationary and rotor blades, and (6) pumping loss generated when water droplets adhere to the surfaces of the rotor blades, wherein a computer is configured to store information to permit selection from among the loss elements on a basis of a calculated wetness fraction, the calculation method comprising: calculating, via the computer, a wetness fraction at each of an inlet and an outlet of each of a stationary blade cascade and a rotor blade cascade; selecting, via the computer, relevant loss from among the loss elements so as to calculate the amount of moisture loss based on the calculated wetness fractions and the information stored in the computer; calculating, via the computer, an amount of each loss selected from among the loss elements; and calculating, via the computer, the amount of moisture loss at each blade cascade on a basis of each calculated amount of each loss selected from among the loss elements.