Dynamic Behavior of an Unbalanced Rotor on Lubricated Bearings

In this paper the dynamic behavior of an unbalanced rotor on journal bearings is experimentally investigated. The static unbalance values are obtained by two adjustable rings. Tests are performed for a variety of lubricant flow rates, static unbalance values, ratios of bearing length-to-diameter and lubricant viscosities. The results of this study show that, from a qualitative point of view, there is good agreement with the theoretical predictions made by Lund and Nielsen, in particular for a bearing with an L/D = 1. However, it is shown that the oil flow rate greatly affects the dynamic behavior; this aspect is not adequately considered in previous theoretical investigations.