Methods of Research of Foil Bearings in START-STOP Cycle in the Presence of Working Medium

Abstract

A method for testing sliding bearings with an elastic bearing liner was presented in the paper with a focus on the issue of selection of particular time intervals of the START-STOP test cycle. Then, results of the tests carried out according to the selected material combinations were presented. The working cycle of foil bearings tested on the test stand was performed in an automatic mode at the set number of sequences start-work-rundown-stop. Due to the highest use of sliding bearings during start and rundown of a machine, this type of tests is essential for selection of relevant sets of material for bearing elements. The article also presents the use of a thermo-visual camera for identification of additional thermal loads and manners of temperature stabilization in the test chamber.

Experimental Study of the Thermal and Wear Characteristics of a Foil Bearing Lubricated with a Low-Boiling Liquid

“…Start/stop tests concerning foil bearings are important because the main reason for the foil bearing wear is the friction between working parts of the bearing, mainly between the top foil and the shaft journal, occurring during the start-up and run-down of the rotating machine and at the instantaneous bearing overloads. Studies into foil bearings in a start/stop cycle allow determining the durability of wear parts of the bearing, especially top and bump foils, as well as journal [41][42][43].…”

Methodology of Testing Foil Bearings in the Start-Stop Cycle in the Presence of a Working Medium - Stabilization of Temperature in the Test Chamber

“…Figure 2. Image from the thermal imaging camera (Moczulak and Miąskowski, 2019) When actions aiming at stabilization of temperature inside the test chamber during the test cycles were undertaken without using any specialistic systems of intake of the generated heat (e.g. Peltier links) it was decided to perform forced air convection around the test chamber.…”

“…In order to determine the temperature rise curve as a function of the number of test cycles, the initial measurements for 200 cycles were performed according to the previously established time interval (Moczulak and Miąskowski, 2019) for selected material pairs. The cycle of foil bearing operation on the test stand was carried out in the automatic mode for the sequence run-up -work -rundown -break (Tr = 3 (s), Tp = 3 (s), Tw = 3 (s), Tn = 10 (s)).…”