Performance Studies of Powder-Lubricated Journal Bearing Having Different Pocket Shapes at Cylindrical Bore Surface

Abstract

It becomes impossible to use conventional fluid film journal bearings in the hot working environments (500–800 °C) due to rapid thermal degradation of lubricating oils. Under this situation, powder lubricants prove beneficial in spite of high friction values associated with them in comparison to lubricating oils. Thus, reduction of friction in powder-lubricated journal bearings is an essential task for making the operation energy efficient. Hence, the objective of this paper is to explore the reduction of coefficient of friction in a powder-lubricated journal bearing employing different pocket shapes (elliptical, parabolic, rectangular, and trapezoidal) placed on bore surface. Based on the investigations reported herein, it is found that the journal bearing having rectangular pocket yields least coefficient of friction among all the cases.

Stability of rotor supported on powder lubricated journal bearings with surface pockets

“…Moreover, the tribological performance of bearings are also improved by surface modifications of bearings using texturing, pocketing, grooving etc. 2,[20][21][22][23][24] Therefore, the objective of this paper is to investigate the dynamic characteristics of powder lubricated journal bearing with pockets of different shapes (rectangular, trapezoidal, elliptical, and parabolic) on the bearing surface. It is observed that pocketed bearing may increase the threshold speed of instability of rotor in comparison with smooth bearing if proper extent of pocket is chosen.…”

“…Substituting equations ( 13) and ( 14) in the continuity equation (2) and integrating along film thickness, the Reynold's equation is obtained as;…”

“…Powder or granular materials can serve as alternative lubricants in extreme environments. [1][2][3][4] Heshmat 5 reported that the pressure developed inside a powder lubricated bearing is remarkably similar to that of a liquid lubricant. Heshmat and his co-researchers have extensively studied the behaviour of powder lubricants in several powder lubricated devices such as dampers, journal bearings, and slider bearings [6][7][8][9][10][11][12][13] etc.…”

Performance analysis of thrust pad bearing using micro-rectangular pocket and bionic texture

“…This enhances the operational reliability of the lubricated interfaces. 18,19,[23][24][25][26][27][28] It is worth noting here that the extent and positioning of textures, microgeometries' shape and size, 20,22,24,[27][28][29][30] and dimple/pocket area density 20,22,29 over pad surface play a significant role in the performance behaviors of bearings. It has been pointed out that the nonoptimized textures may deteriorate the performances of the slider/thrust pad bearings.…”

“…18,19 It has been reported that the presence of certain textures on the bearing surfaces enhance the minimum film thickness and reduce the friction coefficient. [20][21][22][23][24] It has been noticed that the performance behaviors of textured surfaces happen to be strong function of operating parameters, i.e. load, speed, film thickness ratio, and viscosity of oil.…”