A Novel Variable Impedance Hydrodynamic Oil-Film Bearing: Part 2: Experimental Identification of the Steady State and Dynamic Characteristics

Abstract

A novel form of hydrodynamic oil-flm bearing has been examined experimentally to establish both steady state and dynamic characteristics. The novel bearing design is based on a 120" partial arc bearing but contains two recesses to which are attached accumulators. The facility to open or close a valve located between the accumulator and the recesses enables the engineer to effectively tune the in situ. This bearing also has the benefit of being similar in cost to a standard bearing. The oil-film coeficients were obtained F y om t efrequency response function obtained when the system was excited by a pseudo random binary sequence signal. The use of the generalized matrix inversion method to determine the oil-film coefficients from thefrequency response function was found to be some 10 per cent faster than the least squares curve-jitting method. Both methods were shown to produce reliable estimates to extract oil-film coefficients.

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.…”