A Novel Variable Impedance Hydrodynamic Oil-Film Bearing: Part 1: Theoretical Modelling

Abstract

A novel bearing design is presented. The bearing consists of a partial arc bearing into which two recesses are machined. Attached to the two recesses, via remote-controlled valves, are two accumulators. The ability to be able to open and close the valves gives the new bearing design four independent operating modes. Steady state operating characteristics for the bearing were predicted using a finite difference solution to Reynolds' equation. A new mathematical model is proposed for the recess boundary. The model is based on flow continuity and enables afinite difference node to be positioned on the recess boundary. It is demonstrated that the theoretical model proposed predicts steady state characteristics which agree favourably with previously published work and with experimental data. The model was further utilized, in a pressure perturbation algorithm, to obtain predictions of the bearing's dynamic operating characteristics. It is demonstrated that by switching the valves from open to closed, or vice versa, the bearing's characteristics can be altered in situ. I t is also demonstrated that the inclusion of the recesses and accumulators has little effect on the steady state characteristics whencompared to those of a conventional partial arc bearing. It is suggested that the bearing design proposed in this paper has major advantages to offer the rotating machine designer. Use of the bearing enables the operator to vary support characteristics without major re-machining. Furthermore, support characteristics may be varied in situ, without signifcant cost penalties and with little additional maintenance overheads.

An active control for hydrostatic journal bearing using optimization algorithms

“…The active lubrication helps to improve static/dynamics characteristics for hydrostatic bearings. Several authors have done the research for active devices for hydrostatic bearings such as; piezoelectric pushers for bearing (Palazzolo et al, 1989), magneto-hydrostatic lubrication as active lubrication is used by (Kumar and Sharma, 2019), giant magnetostrictive material (GMM) based actuators (Lau et al, 2009), a membrane restrictor (Sha et al, 2020), servo-hydraulic actuators (Rehman et al, 2019c;Rehman et al, 2018), bearings with variable impedance (Ogrodnik et al, 1996), magneto-hydrostatic lubrication under different types of recess shapes (Kumar and Sharma, 2019), a novel piezoelectric membrane restrictor is proposed by (Liu et al, 2016), a high-speed solenoid valve is used to main fluid film gap (Rehman et al, 2019b). Active fluid lubrication is proposed as a solution for modern rotating equipments where demand is clean environment and high speed.…”

Computational analysis of the steady state performance of an adjustable/controllable multi-pad bearing profile under LBP orientations

“…To improve the operational efficiency of high-speed rotating machineries, there is a growing demand in the development of active bearing devices which could control the machine’s operation. Active bearing configurations consisting of hydraulic servo systems, 1 controlled lubrication mechanism through pad orifices, 2–7 variable impedance bearings 8,9 and bearing with piezoelectric pushers, 10–17 movable flexible sleeve 18–22 and adjustable pads 23–28 are developed by various researchers. These bearing configurations were designed to be implemented in industrial applications to overcome the limitations of conventional fluid film bearings in controlling the journal motion during operation.…”

“…Based on the adjustability concept, Ogrodnik et al. 8,9 developed a variable impedance bearing capable of switching the bearing to four different operating modes using two attached accumulators. Similarly, Palazzolo et al.…”

Fuzzy logic–based intelligent control for hydrostatic journal bearing

“…The higher demand of sophistication has made it critical to improve performance of rotating machines by developing active devices that aim to improve dynamic behavior and control vibrations. Researchers have proposed different types of active devices such as active bearing with flexible sleeves, 1 hydraulic actuator bearings, 2 piezoelectric bearings, 3 magnetic bearings, 4 variable impedance bearings, 5,6 and active lubricated bearings. 7,8 Active lubrication is thought to be the ultimate solution for high-speed and clean environment by some researchers.…”