Date of Publication :26th December 2024

Abstract:The detection of coupling misalignment in rotor bearing system has been modeled using rotor torque signals in the present paper. This has been accomplished by modeling the shaft and rotor as a flexible members and formulating the equation of motion of the rotor by adding the inertia torque and torsional shaft stiffness torque to the actual external torque acting on the rotor-bearing system. Generally there exists three kinds of misalignment namely parallel, angular and combined. In the present study, torque signals have been used for the detection of parallel coupling misalignment. To accomplish this finite element analysis has been performed on the commercial software package ANSYS 13.0 and the shaft has been modeled using the Solid 185 element. The unbalance forces has been applied on the rotor along horizontal and vertical directions. Further, the vibration acceleration and torque signals have be en obtained and the chances of misalignment detection using the torque signals is investigated further. For the four cases of parallel misalignment the vibration and torque signals have been obtained. Signals at different speeds namely 25 Hz and 40 Hz have been used for diagonizing the fault. From results, it is concluded that the misalignment has been well detected from vibration acceleration and torque. Especially, such an identification can well be useful in misalignment detection in gas turbines rotor.

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