One of the common issues within the industrial gas turbine fleet is the susceptibility of a can-annular combustors’ fuel manifold cover (support housings) to develop embedded cracks. These cracks, located in the assembly joint of cover plates that create internal passages for fuel delivery to the combustion system, have enough of a driving force to propagate to the surface of the component. Once a crack propagates to the surface, gas has the potential to leak into the enclosure, posing a potential fire and safety risk. Furthermore, cracked fuel manifold covers are prone to increased NOx levels and excessive dynamics. Consequently, operators have the potential for a forced outage due to the failure of the fuel manifold. Currently, the existing solution is to replace the support housings with new or refurbished housings, with prior analyses requiring near perfect fusion.
An ultrasonic inspection procedure has been developed to inspect a combustor’s fuel manifold cover for embedded cracks, which are not currently detectable with FPI or X-ray methods. Through this method, the amount of fusion in the assembly joint is readily obtained, including the ability to understand if the crack is partial-thickness or through-thickness. Parametric fracture analyses, utilizing experimental material test data calibrated to service-exposed components, are conducted to predict the residual life. Coupled with the engine operating data, including the use of cold- or heated-fuels, a recommendation for the remaining useful operation of the support housings can be provided. Ultimately, by completing the ultrasonic inspection and analysis on the support housing/fuel manifold, both the risk of an unplanned outage in the future and the lifecycle management cost to the operator is reduced.