| 摘要 |
PURPOSE:To increase a safety factor in case of a slanted nozzle resonating with a nozzle wake by providing a nozzle or a stationary blade having a slant angle in terms of a nondimensional quantity made larger than a specific value. CONSTITUTION:Expressing the height of a nozzle as HN, an average pitch as PN, and a slant angle as beta, a slant angle alpha of the nozzle satisfies alpha=HN.tanbeta/PN. Hereby, magnification of a resonance response with respect to said alpha is established, whereby the alpha is limited so as to permit a safety factor to be increased when the nozzle resonates with a nozzle wake. Namely, the nondimensional quantity indicative of the slant angle is made larger than 1.3. Hereby, the magnification of the resonance response becomes less than 1 as to resonance of a second mode, whereby a safety factor of the same order or more as in a case of the nozzle being not slanted can be assured, while the magnification becomes less than one third in first mode resonance, and hence the safety factor more than three times of the case of the nozzle being not slanted can be secured. |
