Maps of Vibrational Symptoms of Bearing Misalignment Defects in Large Power Turboset

The article presents results of research activities oriented on creating a pattern of the dynamic state of a turboset in the presence of a defect consisting in the misalignment of its bearings. The dynamic state of the machine, described by its vibration pattern, is presented on maps showing vibration intensities of selected machine components as a function of misalignment of individual bearings. Similar maps were also created to present changes of static load caused in all bearings by bearing misalignment. The work contains the exemplary set of maps, which illustrate vibration levels of all bearings as a function of displacement of each turboset bearing in any direction in relation to its proper position. The maps are drawn in the possible bearing displacement ranges, between −5mm and +5mm to any direction. Assuming critical values of bearing vibration and bearing loads, the permissible bearing misalignments can be determined basing on bearing vibration and bearing load maps. Graphs of so defined permissible displacement areas were found for all bearings and are included in the paper. The work was done by means of computer simulation of bearing misalignments in the numerical model of 13K215 turboset by means of MESWIR computer code package. The present work is a continuation and extension of author’s earlier research activities in the area of bearing misalignment defect, which results were presented among others on ASME Turbo Expo 2006 Conference. The bearing misalignment is the very frequently observed inefficiency in large machines of this type; therefore results of the investigations may have important practical application. Although the vibrational maps presented in the article have been created for particular machine, value of this work consists in possibility of application of the presented methodology to any similar machine. Obtained this way vibrational maps may be put to use in vibration diagnostics of the turboset.