Numerical analysis on the start behavior of rough journal bearings during the gear pump meshing cycle

Abstract

<jats:p> In this paper, the transient lubrication characteristics of hydrodynamic journal bearings during the external gear pump meshing cycle are studied. In the bearings lubrication calculation part, a numerical model is developed to assess the transient lubrication during the initial start-up of an aero gear pump. The model takes into account the effects of surface topography, asperities contact, and pump start-up speed. In the pump simulation part, the flow inside pump and bearing load environment are analyzed by a computational fluid dynamics model. Then a simulation method is presented to solve the problem of pump-bearings system, considering the pump’s influence during bearings lubrication calculation. To gain insight, results of a series of simulations with illustrative examples are presented. The variation of the startup lubrication performance under load conditions corresponding to the pump internal flow field is acquired. The results show that bearings operate from mixed-lubrication to hydrodynamic-lubrication state with changed load-supporting effects during the startup. The load-supporting effects and film rupture boundary are directly related to the pump load fluctuation, but the center trace is slightly influenced except on the hydrodynamic-lubrication state. </jats:p>

Identifying the influence of design parameters of single-chamber hydrostatic bearing of fuel pump on its main characteristics

“…A scheme of a hydrostatic bearing with one supporting chamber located under the line of action of the external force is proposed. The above analysis of the influence of the design parameters of a single-chamber hydrostatic bearing on its characteristics was not considered in [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The calculation results show the possibility of using a single-chamber hydrostatic bearing in fuel pump supports.…”

“…However, the work does not pay attention to the use of hydrostatic effects in the model built, which would eliminate the influence of surface roughness on the operation of the sliding bearing. Paper [7] studied the transient lubrication characteristics of hydrodynamic journal bearings during the external gearing cycle of a gear pump. A numerical model is constructed to evaluate transient lubrication during initial startup of an aircraft gear pump.…”

“…However, the work does not pay attention to the use of hydrostatic bearing designs, which can significantly reduce the temperature of the lubricant. Work [10] examines the transient characteristics of the lubrication of plain bearings inside an aviation fuel gear pump under complex variable loads. A model for calculating transient processes has been built.…”