An experimental study of transient thermal effects in a plain journal bearing

The present study deals with the experimental determination of temperature distribution in a plain, steadily loaded journal bearing, during transient thermal periods such as start-up or slow changing in velocity. A number of chromel-alumel thermocouples, placed circumferentially in the median sectio n of the bearing, are used in order to carry out the measurements. The temp erature at film-shaft interface is also measured by means of a chromel-alum el thermocouple and a mercury transmitter The effects of journal speed and load on bearing temperature and fluid friction torque are analyzed. The bea ring temperature increases considerably with the increase of rotational spe ed. In addition, for slight bearing loads the bearing temperatures are grea ter than for higher loads, due to the oil recirculation. The fluid friction torque increases at start-up and afterwards tends to decrease because of t he temperature rise which decreases the oil viscosity.