Dynamic Shafting Alignment Algorithms Considering Sensitivity Analysis and Its Application

A method for dynamic alignment calculation of a large turbogenerator shafting is proposed. The method can analyze bearing load and bearing load sensitivity. Shafting alignment is made up of two parts:static alignment and dynamic alignment. Static alignment forms the basis of dynamic alignment, its mathematical model is deduced by transfer matrix method, the shafting static characteristic parameters under specific alignment installation requirements were obtained afterwards. Based on superposition method, bearing sensitivity analysis is performed to find the impact of slight bearing elevation change of the static alignment result. Above static alignment, dynamic shafting alignment considers the internal geometry of bearing under rotating state, static Reynolds equation is solved by the finite difference method and the relative position relationship of the center of journal and bearing are obtained. For static characteristic parameters calculated by static alignment and bearing sensitivity analysis, the calculation accuracy is verified by finite element software. The alignment model and codes in this paper can be a tool for the installation and safety analysis of large-scale shafting with three-point or four-point supports.