Experimental Investigation of a Large Tilting-Pad Journal Bearing—Comparison of a Flooded and Non-Flooded Design

Abstract

In tilting-pad journal bearings (TPJB), power loss corresponds to the internal friction in the shearing of the oil. Besides the lubrication gap, intermediate spaces between the pads account for a notable amount of frictional losses. Against the background of increasing demands for efficiency and sustainable use of resources, the reduction of power loss takes a key position in the further development of bearings. In our research, we compare two bearing lubrication concepts of a five-pad TPJB. Our objective is to work out the influence of different lubrication methods and bearing housing designs on the bearing operation characteristics. We conduct experimental testing of a 500mm TPJB in two different bearing configurations with respect to the lubrication concept: an oil-flooded and non-flooded bearing design. In the flooded bearing design, oil is supplied via spray-bars and axial seals ensure the inter-pad spaces to be completely filled with oil. The non-flooded design comes without axial seals but oil drain channels to avoid oil accumulation in the bearing. In the latter design, oil is fed in via leading edge grooves (LEG). For the non-flooded bearing design, the experimental data show that the unloaded pads are not completely filled with oil and therefore, no pressure build-up occurs. The absence of additional load on the lower pads compared to the flooded design results in an increase of minimum film thickness. With the non-flooded design, power loss at high speeds is reduced to almost half. As a result, the efficiency of the entire turbomachinery application can be considerably improved.

Turbulence Effects in Tilting Pad Journal Bearings: A Review

“…The tested bearings reported in Table 2 can be grouped by size with the smaller diameters ranging from 100 to 200 mm [39,44,[46][47][48]56,64,65,69,71,72] and the larger ones from 280 to 580 mm [8,43,45,49,55,[66][67][68]70,73,74]. The length to diameter ratio goes from a minimum of 0.3 [56] to a maximum of 1.33 [39].…”

“…The experimental facility used by Hopf and Schüler [8], and other researchers after them [49,66,68], deserves particular mention for the high resolution of measurements of oil film thickness and pressures and shaft temperatures. The hollow shaft is equipped with two capacitive distance sensors, two piezoelectric pressure sensors and several thermocouples.…”

Experimental Study on Low Speed Lubrication Characteristics of Large Tilting Pad Bearings

“…With the development of computer and testing technology, the problems of tilting pad bearings in practical applications are found, dealt with and a new model to solve the problem is established. The mathematical model of fluid lubrication of tilting pad bearings is developed from a simple two-dimensional thermo hydrodynamic analysis model to a complex three-dimensional thermo hydrodynamic analysis model, and further to a complex three-dimensional thermoelastic hydrodynamic analysis model, whose computational accuracy and speed have been continuously improved [6] [7] .The effects of turbulence effect [19] [20] , rotor tilting and misalignment [17] [18] , and cavitation effect on the bearing performance such as power consumption, lubrication characteristics, temperature rise of bearing shell, and dynamic characteristics at high speeds are also considered in the theoretical analysis.…”

Advances in Lubricated Bearings

“…Solving the issues appearing during operation of all of these bearings in complex drive trains requires innovative approaches based on the experience and the physical understanding of the particular phenomena by tribology engineers. This Special Issue (SI) contributes to the latest steps in understanding bearing operating behavior [1][2][3][4][5][6], its interaction with lubricants [7,8], and its role as a component in the drive train [9][10][11][12].…”

“…Stottrop et al [1] and Buchhorn et al [2] investigate the operating behavior of original size large turbine tilting-pad bearings on a special test rig. The first study [1] compares the performance of the same test bearing with different lubrication designs provoking flooded conditions in the first case and non-flooded ones in the second case. The non-flooded design exhibits higher film thickness and lower power loss while the temperature level does not change significantly.…”