A notable characteristic of electro-rheological (ER) fluid is the variation of its apparent viscosity with the application of an electric field. The application of this characteristic to the performance of squeeze film damper of a flexible rotor is investigated in this paper. It is shown experimentally that by controlling the supporting damping capacity continuously, rotor vibration can be reduced remarkably a wide range of rotating speed. Moreover, the study indicates experimentally that there exists an optimum supporting damping for every vibration mode.

The temperature distributions in full circular bearings were measured in a test rig. The effects of journal speed, lubricant viscosity, and clearance ratio on the maximum bearing temperature and its location were discussed. The results were compared with the theoretical analysis by the present authors and good agreement was obtained over the wide range of operating conditions. The maximum bearing temperature is found to increase considerably with the increase of speed or lubricant viscosity and also with the decrease of clearance ratio. Its angular position is found to vary with speed and clearance ratio. These phenomena can be explained by the characteristics of maximum film temperature in the oil film.

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This paper deals with a theoretical and experimental investigation on the cooling effect of supply oil in a circular journal bearing. Bearing frictional torque, temperature distribution in the bearing bush as well as on the journal surface, eccentricity ratio, oil temperatures at the inlet and outlet, and oil flow rate were measured. A transparent plastic bearing was also used to observe the film flow near the oil groove as well as in the cavitation region. The mixing coefficient was introduced into the thermohydrodynamic analysis in order to determine the initial temperature distribution of the film just behind the inlet. The mixing coefficient was obtained experimentally and its value mainly ranges from 0.4 to 0.8.For the film temperature distribution, the following energy equation is obtained: 414/Vol. 105, JULY 1983 Transactions of the ASME Copyright © 1983 by ASME Downloaded From: http://tribology.asmedigitalcollection.asme.org/ on 06/25/2015 Terms of Use: http://asme.org/terms

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