Design and Stress Analysis of Extraterrestrial ... - The Black Vault

Vibrational stability is determined by the speed of the rotor
at which, as a result of vibrations, the completeness of the fluid
film in the bearing is disturbed and a ccntact between shaft and
bearing occurs. The higher stiffness of hydrostatic bearings
potentially determines their higher resistance to vibration.
With greater revolutions of a rotor installed on hydrostatic
bearings (10,000-30,000 rpm), we should consider the influence of
dynamic effect (the load-lifting capacity of such a bearing is
somewhat higher with rotation taken into account than it is without
accounting for rotation) and more strictly define the zone of
rotor equilibrium, taking into account vibrational stabilLty.
The sensitivity of hydrostatic bearings to the direction of
the external load, as was found, is substantially less than 1hat
of hydrodynamic bearings, in which it depends upon both the point
of supply of the lubricating liquid and the relative motion of the
rubbing surfaces which form the liquid wedge.
The effect of the supersaturation of vapor
and its condensation on turbine operations
Along with the difficulties involved in solving purely structural
questions in the planning of turbines for extraterrestrial power
plants, there is also the difficulty of solving such questions as
the supersaturation of vapor expanding on the turbine blades and
its condensation inside the turbine.
The essence of supersaturation is the fact that with the rapid
expansion the working medium does not manage to be condensed and
can be presented in the form of vapor although, according to the
condition of thermodynamic equilibrium, partial condensation should
occur. This reduces the efficiency of the turbine.
The radial extent of the turbine blades for the oversaturated
state of vapor should be less than for equilibrium. Therefore,
a turbine cascade designed with partial condensation taken into
account passes more of the working medium.
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