A Novel Method to Achieve Fast Multi-Objective Optimization of Hydrostatic Porous Journal Bearings Used in Hydraulic Turbomachine

Abstract

The hydrostatic journal bearing equipped with a carbon-fibre-reinforced carbon-based porous bushing is employed in the hydraulic turbomachine. The bearing exhibits high load capacity, but may unduly consume pressurized lubricant. This study aims to maximize the load capacity and minimize the feeding power. The journal radius, nominal clearance, porous bushing length, porous bushing thickness, feeding pressure and material permeability are selected to optimize. A fast optimization method is proposed, integrating an in-house porous journal bearing solver (PBS), sampling method, surrogate model and genetic algorithm. Behind PBS, a theoretical flow model based on the Reynolds lubrication equation and the Darcy equation is established, and a new numerical method based on the finite difference method is proposed. PBS substitutes ANSYS FLUENT by calculating bearing performances accurately and instantly, which is the first novelty to facilitate optimization. Then, artificial neural networks are trained as error-free and time-efficient surrogate models to produce bearing objectives in the evolution, which is the second acceleration highlight. The running time is reduced significantly. The load capacity is improved by 68.1%, whereas the feeding power declines by 50.5%. In the optimized case, a sharp pressure hump leads to greater load capacity, while the radial velocity decreases, resulting in reduced feeding power.

Identifying the influence of design parameters of a hydrostatic bearing in an aircraft fuel pump on its static characteristics

“…An unconventional arrangement of load-bearing chambers on the working surface of a hydrostatic bearing is proposed. The above analysis of the influence of design parameters on the static characteristics of a hydrostatic bearing was not considered in [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The results allow for a more rational design of hydrostatic bearings and show the possibility of their use in aircraft fuel pumps.…”

“…However, the cited work does not pay attention to the turbulent flow of lubricant, which is typical for low-viscosity fluids and can have a significant impact on the characteristics of the bearing. Paper [3] discusses a new method for optimizing hydrostatic porous plain bearings used in hydraulic turbomachines. The hydraulic turbine machine uses a hydrostatic plain bearing equipped with a porous carbon-based bushing reinforced with carbon fiber.…”

“…In the literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], there is no information on the study of the influence of the circumferential arrangement of load-bearing chambers on the working surface of a bearing on its load-bearing capacity and flow of working fluid. The influence of changes in the temperature of the working fluid at different positions of the load-bearing chambers in the bearing on its load-bearing capacity and fluid flow has also not been considered.…”

Study of the effects of modified draft tube with inclined conical diffuser on draft tube and upstream region

“…64%Qbep. A non-slip boundary condition was applied to the walls [19,20]. The SIMPLEC algorithm was chosen to achieve the coupling of velocity and pressure equations.…”