A. M. Mikula, Research Engineer
Kingsbury, Inc., Philadelphia. Pa. 19154
Member, ASLE
An analysis of tilting-pad thrust bearing operating temperatures
is described. The analysis includes an evaluation of various temperature
locations based on their ability to reflect bearing operating
conditions. Experimental results for a 267-mm (1O.5-in) 8-pad
thrust bearing indicates that while a babbitt location on the trailing
edge of a pad is often the hottest, the 75/75 percent location provides
temperature data on the high-pressure region of the pad. Babbitt
temperatures also provide a convenient indicator of the transition
from laminar to turbulent flow in the oil film.
Introduction
Bearing temperatures generated during the operation of
a tilting-pad thrust bearing can provide a convenient means
of assessing bearing performance. Widespread use of thermocouples
and resistance temperature detectors (RTD's)
has made possible the collection of this potentially valuable
temperature data. Unfortunately, selecting the proper location(s) to place these devices is complicated by the numerous candidates within the bearing or lubricant. Unless the proper location(s) is monitored, the temperature measurements
made will prove to be very poor indicators of
overall bearing performance. Selection should be based on
the ability of the selected location to reflect actual operating
conditions, and not on the ease of installation of the measuring
device.
This paper presents the results of a series of tests conducted
on a tilting-pad thrust bearing to investigate the
temperature behavior of various locations. Thermocouples
were employed to measure the temperatures of the bearing
pads and the lubricant.
The bearings were evaluated using a light turbine oil with
a viscosity of 0.027 Pa·s @ 37.8°C and 0.006 Pa·s @ 98.9°C
(150 ssu @ 100°F and 43 ssu @ 210°F) supplied at 46°C
(115°F), for applied loads ranging from 0-3.45MPa (0-500 psi) and shaft speeds ranging from 4000 to 13,000 rpm.
The influence of lubricant supply method and flow rate are
also evaluated. By reporting the influence of operating conditions
on various locations within the bearing and lubricant,
it is hoped that this paper will provide the information
necessary to select the proper location to monitor bearing
performance.
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