A slotted pocket gas damper seal has been experimentally evaluated on a flexible rotor test rig for rotor vibration reduction properties. For unbalance response tests, the experiments were conducted at several seal inlet pressures out to 14.5 bar (210 psia), and the rotor speed ranged up to 8,000 rpm, which was well above the damped first critical speed of the flexible rotor. The influence of gas pre-swirl and seal eccentricity on the seal dynamic performance was investigated in the tests. Experimental results showed that the slotted pocket damper seal provided high positive damping and small positive stiffness in the tested pressure range. Comparisons of seal dynamic characteristics and leakage were made between the slotted pocket damper seal and a conventional pocket damper seal tested previously on the same test stand. The stability characteristics of the slotted pocket gas damper seal were also experimentally evaluated at 12,000 rpm, the maximum operating speed of this test rig. Test conditions involved three inlet pressures up to 20.7 bar (300 psia) and intentional pre-swirl gas flows. Experimental results demonstrated that the slotted pocket damper seal was rotordynamically stable at high speeds without any subsynchronous vibration in the frequency spectrum measured using proximity probes for the test rotor.
An experimental program was conducted to measure film temperature in all the pads of a 127-mm (5-inch) diameter five-shoe tilting-pad journal bearing, load-between-pad configuration. Film tempemture measurements were taken both in the circumferential and mial directions of the pads at dqferent speeds, loadr, and jlows. The tests were conducted in speeds ranging from 3000 to 13 000 rpm, unit bearing load range of 34.5 x 1 o4 to 172.4 x 1 o4 ~l m ' (50 to 250 psi) and at flows of 0.177, 0.252 and 0.379 Lls (2.8, 4.0, and 6.0 gpm). The actual power losses have also been compared to the theoretical power losses.Results of these tests are presented in this paper.
An experimental program was conducted to relate bearing film temperatues to oil discharge temperature. Results for a five-shoe tilting-pad journal bearing show that film temperatures are substantially higher and more sensitive to load and speed changes than is discharge oil temperature. Conversely, film temperature is less sensitive to changes in flow. It was also noted that the rate of change of film temperature is significantly greater than the rate of change of discharge oil temperature when the bearing is subjected to load change, which is a desirable characteristic for a monitoring and control system. These results should provide a more rational basis for the evaluation of bearing performance when film temperatures are reported.
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