چكيده به لاتين
Abstract:
The growing demand for power is putting tremendous stress on existing power plants for generating electricity. The plants are being operated for longer periods of time under heavy load conditions. Reliability of key components of the power plant such as gas turbines is of prime importance. In this thesis by doing field study on the 60 land base gas turbines in Iran Power Plant Repairs (IPR) Company and using failure mode and effect analysis technic determined that failure of blade is one of the most important event in power plant. Therefore, to prevent further failures, a failure root cause analysis was carried out. In order to explore the major cause of fracture of 2 blades, the visual inspection, chemical composition and microstructure of the fractured blade were analyzed by chemical analysis, optical metallography (OM), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). An analytical calculation parallel to the finite element method was utilized to determine the static stresses due to huge centrifugal force. The dynamic characteristics of the turbine blade were evaluated by the finite element modal and harmonic analyses. Finally, according to the log sheet records and by using a Campbell diagram there was a good agreement between the failure signs and FEM results which showed the broken blade has been resonated by the third vibrational mode occasionally before the failure occurred.
Keywords: Land Base Gas Turbine, Maintenance, Failure of Blade, Metallography, Hot Corrosion and Fatigue, FEM.
