| 摘要 |
PROBLEM TO BE SOLVED: To reduce a time necessary for measuring an area change of a throat area. SOLUTION: This area calculation method for the throat area takes nozzle blade data in a 3DCAD (step S1), divides a coordinate space into ten spaces in the height direction of the nozzle blade (step S2), vertically projects a boundary curve between a belly of one nozzle blade and a trailing edge on a back face of the other nozzle blade in each divided area to form a projection curve (step S7), generates an outer passage and an inner passage connecting both the upper ends and both the lower ends of the boundary curve and the projection curve (step S8), finds a nearly trapezoidal area surrounded by the boundary curve, the projection curve, the outer passage and the inner passage (step S9), and adds the calculated areas to calculate the area of the throat area (step S10). By use of the area calculation method, a ratio of the area of the throat area based on the data on the nozzle blade whose angle is changed by a prescribed throat adjustment angle and a design state is calculated and is displayed as the area ratio of the throat area.
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