Abstract:

ESDU 95023 introduces a computer program (ESDUpac A9523) that provides a dynamic simulation of the rotor/bearing system through a cycle of run-up at constant acceleration, a period at constant operating speed and a coast-down at constant acceleration with or without a speed dependent external loading. Selected parameters such as deflections and forces may be recorded in a form suitable for plotting. It will determine the steady-state response to imbalance, the nominal threshold speed for oil-whip instability, and synchronous harmonic response orbits. The rotor model is a single mass mounted centrally on a flexible, massless shaft with a bearing at each end; the bearing model is that of ESDU 93005 and ESDU 93006 and takes account of the change in lubricant viscosity with bearing load or speed. The input to the program is explained and illustrated with a number of worked examples that also show how the program is used to simulate an operating cycle of arbitrary complexity. Databases of lubricant and bearing coefficient data are provided and may be edited. Input data are validated and a list of possible error messages is given together with guidance on appropriate responses.