Cooled Pads for Tilting-Pad Journal Bearings

Abstract

Tilting-pad journal bearings (TPJBs) are widely installed in rotating machines owing to their high stability, but some drawbacks can be noted, such as higher cost with respect to cylindrical journal bearings and thermal issues. High temperatures in the pads correspond to low oil-film thicknesses and large thermal deformations in the pads. Therefore, the restriction of the maximum temperature of the bearing is a key aspect for oil-film bearings. The temperature reduction is generally obtained by adopting higher oil inlet flowrates or suitable oil nozzles. In this paper, the idea of using cooled pads with internal channels in which an external cooling fluid is circulated will be applied to a TPJB for the first time. The three-dimensional TEHD model of the TPJB, equipped with a cooled pad, will be introduced, and the results of the numerical simulations will be discussed. Several analyses have been performed in order to investigate the influence of cooling conditions, such as the type, flowrate, inlet temperature and number of cooled pads. Two types of pad geometry with different cross-sections of the cooling circuit, namely, circular and six-square multi-channel sections, have been compared to the reference bearing with solid pads. Simple experimental tests were performed by means of a test rig equipped with a cooled pad bearing obtained with the additive manufacturing process, thus showing the effectiveness of the solution and the agreement with the predictions.

Investigation of PEEK Lined Pads for Tilting-Pad Journal Bearings

“…Convective boundary conditions with the convection coefficients q oil = 50 W/m 2 .K for all the surfaces in contact with the lubricating oil at supply temperature of T supply = 40 • C and q air = 20 W/m 2 .K for the surfaces of the two portions of the shaft in contact with the air at room temperature T room = 30 • C have been assumed. More details about the thermal model can be found in [21].…”

Static Characteristics of a Tilting Five-Pad Journal Bearing with an Asymmetric Geometry

“…− ( ) = 0 Readers are strongly recommended to refer to [11,29] for a detailed description of the model. Each pad consists of two different parts: a base part (steel) and an anti-friction layer (Babbit metal with a thickness of 3 mm).…”

“…In this study, a convection boundary condition with a constant coefficient of q = 50 W/(m 2 •K) is applied on the pad surfaces contacting lubricating oil at supply temperature (T supply = 40 • C and q air = 20 W/(m 2 •K)) in order to evaluate the distribution of the pad temperature. The constant convection coefficient q = 50 W/(m 2 •K) was also used in some previous publications [11,29,31,32]. Actually, this value is not uniform at the pad peripheries and it changes with the conditions of the oil flow around the pad [19].…”

“…Cooled pads in five-pad TPJBs instrumented with several internal channels were presented in [11]. The fluid system was circulated for the purpose of external cooling.…”

Cooled pads with bioinspired gyroid lattice for tilting pad journal bearings: Experimental validation of numerical model for heat transfer

“…To overcome the production complexities of the cooling circuit, Additive Manufacturing (AM) technologies can be used. Chatterton et al in [16] address this topic, by considering a journal bearing and a cooled pad with an M-shaped channel. Firstly, they created an advanced Thermo-Elastic-Hydro-Dynamic model to compare the performances of different channel cross sections and then they made a functional prototype of the component [17].…”