FAULT DETECTION INSPECTION ANALYSIS OF A GAS TURBINE USING FREQUENCY DOMAIN

Abstract

Analysing torsional vibration (TV) of the rotor shaft system can mitigate long down times and high maintenance cost. TV analysis can also eliminate faults such as shaft crack, coupling misalignment and rotor imbalance are some of the common causes of TV in the gas turbine (GT). The rotor shaft is a major mechanical component of the gas turbine engine (GTE) responsible for power generation and power transformation. Reliability and performance of the system is mostly determined by the efficiencies of the rotor system. This research therefore presents a computer based analytical solution method for TV to be used in fault detection. In arriving at the method, a single degree of freedom system was modeled and relevant equations were derived. These equations was programmed using Matlab and results was implemented with the data of an operational existing plant. It was discovered that input parameters such as norminal speed 3000 rpm, spring stiffness is 200 GN/mm, mass moment of inertial 22071.5 kgm2 and optimum power capacity is 125 mW. The software developed in this research will be useful for training in tertiary institutions and easy for both technical and non-technical personnel on TV analysis of GTE. A total of 5*10-11m, 4.3 *10-10 m/s and 1.4*10-10 m/s2 is shown as the angular displacement, velocity and acceleration. An angular frequency of 314 to 320 hertz was used in this analysis. It was observed that the GT used in this analysis is fairly new and therefore healthy. No fault was detected and values of angular displacement, velocity and acceleration was observed to be relatively small.