流体中における回転車軸の危険速度

概要

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The critical speed of a shaft rotating in fluid contained in a casing is differ from that in vacuum. In this paper the effects of fluid upon the critical speed are calculated and compared with the experimental results. Let ω be the angular velocity at which a shaft whirls with an eccentricity of d and Ω be the angular velocity at which the shaft revolves about its own axis. Then the critical speed in fluid (1) drops for the range [numerical formula] and has a minimum value at. [numerical formula] when [numerical formula] (2) also drops as r_i/r_o tends to unity at a certain value of ω/Ω in the above range (3) rises up for ω/Ω and (4) drops as the ratio of the density of the material of the shaft to that of the fluid becomes small, where r_i is the radius of the shaft and r_o is that of a casing. This calculated results well coincide with the results experimented at ω/Ω=1 and can be applied to about [numerical formula] When [numerical formula], the effects of fluid are negligibly small. Taking the gyroscopic effects into considerations, the frequency of the shaft drops as the outward force due to fluid acts on it.
1959-03-25