On the future of controllable fluid film bearings

This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric actuators are used. The ideas of combining control techniques, informatics with hydrodynamic, thermo-hydrodynamic, elasto-hydrodynamic and thermo-elasto-hydrodynamic lubrication techniques are carefully explored in this paper, considering theoretical as well as experimental aspects. The main goal of using controllable fluid film bearings is to improve the overall machine performance by: controlling the lateral vibration of rigid and flexible rotating shafts; modifying bearing dynamic characteristics, such as stiffness and damping properties; increasing the rotational speed ranges by enhancing damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing start-up torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable fluid film bearings can act as “smart” machine components and be applied to rotating and reciprocating machines with the goal of avoiding unexpected stops of plants, performing rotor dynamic tests and identifying model parameters “on site”. Emphasis is given to the controllable lubrication (hybrid and active) applied to different types of oil film bearings under different lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted, trying to foresee the future trends of such mechatronic devices

Comparative analysis of neural network and regression based condition monitoring approaches for wind turbine fault detection

This paper presents the research results of a comparison of three different model based approaches for wind turbine fault detection in online SCADA data, by applying developed models to five real measured faults and anomalies. The regression based model as the simplest approach to build a normal behavior model is compared to two artificial neural network based approaches, which are a full signal reconstruction and an autoregressive normal behavior model. Based on a real time series containing two generator bearing damages the capabilities of identifying the incipient fault prior to the actual failure are investigated. The period after the first bearing damage is used to develop the three normal behavior models. The developed or trained models are used to investigate how the second damage manifests in the prediction error. Furthermore the full signal reconstruction and the autoregressive approach are applied to further real time series containing gearbox bearing damages and stator temperature anomalies.The comparison revealed all three models being capable of detecting incipient faults. However, they differ in the effort required for model development and the remaining operational time after first indication of damage. The general nonlinear neural network approaches outperform the regression model. The remaining seasonality in the regression model prediction error makes it difficult to detect abnormality and leads to increased alarm levels and thus a shorter remaining operational period. For the bearing damages and the stator anomalies under investigation the full signal reconstruction neural network gave the best fault visibility and thus led to the highest confidence level

On The Adjusting Of The Dynamic Coefficients Of Tilting-pad Journal Bearings

This paper gives a theoretical and experimental contribution to the problem of active modification of the dynamic coefficients of tilting-pad journal bearings, aiming to increase the damping and stability of rotating systems. The theoretical studies for the calculation of the bearing coefficients are based on the fluid dynamics, specifically on the Reynolds equation, on the dynamics of multibody systems and on some concepts of the hydraulics. The experiments are carried out by means of a test rig specially designed for this investigation. The four pads of such a bearing are mounted on four flexible hydraulic chambers which are connected to a proportional valve. The chamber pressures are changed by means of the proportional valve, resulting in a displacement of the pads and a modification of the bearing gap. By changing the gap, one can adjust the dynamic coefficients of the bearing. With help of an experimental procedure for identifying the bearing coefficients, theoretical and experimental results are compared and discussed. The advantages and the limitation of such hydrodynamic bearings in their controllable form are evaluated with regard to application on the high-speed machines.38370070

Mancal Segmentado Com Filme De óleo Ativo

Patente de Invenção "MANCAL SEGMENTADO COM FILME DE ÓLEO ATIVO". A presente invenção se refere a um mancal segmentado com um sistema de controle hidráulico para reduzir as vibrações das turbinas utilizadas em sistemas rotativas. O mancal, ora proposto, é composto de quatro segmentos móveis, dois na direção horizontal (1a) e (1c) e dois na direção vertical (1b) e (1c), compostos de duas peças (2) e (3) fixadas e seladas uma a outra, através dos parafusos (4) e do conjunto vedante (5), ditas peças (2) e (3) formam um pequeno reservatório (6), onde o par da horizontal (6a) e (6c) é conectado a urna servoválvula (7a) na horizontal e o par da vertical (6b) e (6d) é conectado a uma servoválvula (7b) na vertical, sendo os segmentos dotados de superfícies sobre as quais desliza o rotor (8) e onde são construídos dos orifícios igualmente espaçados (9), ditos orifícios (9) atravessam e peça (3) estabelecendo uma ligação entre a folga radial (10) do mancal e o pequeno reservatório (6), sendo o mancal dotado, ainda de sensores de deslocamento (11a) e (11b) e de sensores de pressão (12a), (12b), (12c) e (12d).BR9403084 (A)F16C32/06F16C32/06BR19949403084F16C32/06F16C32/0

Medidor MecatrÈnico De Perfil De Pista Para Utilização Na Indústria Automobilìstica.

Compreendendo uma massa suspensa (1), eixo de guiagem da massa suspensa (2), base do eixo de guiagem da massa suspensa (3), eixo de escalonamento (4), viga transversal de sustentação frontal (5), viga transversal de sustentação intermediária (6), viga transversal de sustentação traseira (7), viga longitudinal de sustentação (8), cruzeta de medidor de perfil de pista (9), viga longitudinal do medidor de perfil de pista (10), sistema de guiagem da mola do medidor de perfil de pista (11), roletes de contato ou apalpadores do medidor de perfil de pista (12), lâmina flexível (mola torsional) (13), mola de compreensão do medidor de perfil de pista (14), e mola de sustentação da massa principal (15).BR9804468 (A)G01C7/04G01C7/04BR19989804468G01C7/04G01C7/0