A novel idea of using giant magnetostrictive material (GMM) based actuators for journal bearing control is presented in this paper. Frequency response tests on GMM actuators and a journal bearing system were examined. The performances of the system running at various journal shaft rotational speeds under control were investigated. With the aid of GMM actuators, the performances on journal shaft...

High power industrial machinery such as steam turbines and large pumps use journal bearings as rotor supports because this type of bearing is a high load carrying capacity. However, abnormal operating conditions in the journal bearings will degrade machine performance, shorten life time and increase the risk of operation. Bearing condition monitoring can detect faults at early stage and hence m...

This paper presents how the refrigerant dissolved in oil affects on Journal bearings reliability. The bearing model test is performed using the hermetic test apparatus. The oil film pressure is measured under several types of bearing grooves, L/D ratios and mixing ratios of refrigerant to oil. As a result, the means by which the refrigerant dissolved in oil causes damage to journal bearings is ...

Fluid film forces are generated in multirecess journal bearings by two types of lubrication mechanism: the hydrostatic lubrication in the bearing recesses and hydrodynamic lubrication in the bearing lands, when operating in rotation. The combination of both lubrication mechanism leads to hybrid journal bearings (HJB). When part of hydrostatic pressure is also dynamically modified by means of hy...

This paper describes the experimental characteristics of cantilever type journal bearings in reciprocating compressors for HFC-134a. The purpose of this study is to compare the effects of bearing material, chemically treated shafts, bearing stiffness and refrigerant solubility in the oil to the characteristics of journal bearings lubricated with a mixture ofHFC-134a and lubricating oil As a res...

Isothermal journal bearings have been developed by incorporating heat-pipe cooling. The heat pipe assists in spreading heat rapidly along the bearing circumference, resulting in a very small temperature gradient, low peak temperature, and stable transient thermal behavior. This paper presents a model for the isothermal journal bearings and the results of analyses. The heat pipe in the isotherma...

Present study is undertaken to optimize the lubrication reliability and frictional loss of the dynamically-loaded jownal bearing with R600a refrigerant application. A mathematical model is developed for analyzing the dynamics of the journal bearing system with the mobility method. It takes into account the effects of the refrigerant species, aspect ratio, clearance ratio and surface roughness. ...