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Nagy D.,Institute of Aircraft Propulsion Systems | Staudacher S.,Institute of Aircraft Propulsion Systems
International Journal of Power and Energy Systems | Year: 2011

Gas turbine maintenance is heading towards full condition-based monitoring since the pressure on life cycle cost is ever increasing. Nevertheless, in currently operating machines, a minimum number of measurements is used because of the associated costs and issues of reliability which are linked to any sensor. Therefore, it is an ongoing quest to define an integrated gas turbine health monitoring system which supports the engineers in their difficult task of finding possible faulty modules or engine parts during service. This paper presents a novel health monitoring process approach, dealing simultaneously with single fault events and gradual deteriorations of the gas turbine. The modular buildup of the presented process is capable to use purpose-built algorithms provided by an integrated detection algorithm for an autonomous decision between the deterioration types to analyse the health of a gas turbine. The health monitoring process is also capable of robust fault identification due to measurement losses out of the in-service instrumentation. In that case, decision guidance is provided for the engineer to isolate the most likely faulty component. Integrated information fusion capabilities between thermodynamically and non-thermodynamically measurements (if available) increase the successful fault identification and fault diagnosis. As a design feature for new in-service instrumentations an optimal measurement selection algorithm is capable to vote the needed measurements for a satisfactory health monitoring of a gas turbine. The health monitoring system is designed as a user friendly software package with a graphical user interface. An adaption of the health monitoring system to a given gas turbine is guaranteed through an interface to a thermodynamic model of the monitored gas turbine.

Schneider C.M.,Institute of Aircraft Propulsion Systems | Schrack D.,Institute of Aircraft Propulsion Systems | Rose M.G.,Institute of Aircraft Propulsion Systems | Staudacher S.,Institute of Aircraft Propulsion Systems | And 2 more authors.
10th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2013 | Year: 2014

This paper addresses the unsteady formation of secondary flow structures inside a rotor passage. The first stage of a two-stage low pressure turbine is investigated at a Reynolds Number of 75000. The configuration represents the third and the fourth stages of an engine low pressure turbine. The vane-rotor interactions at hub are discussed in the relative frame of reference using the streamwise vorticity to identify the flow structures and interaction processes involved. A multi-stage URANS prediction which is validated by time-averaged five-hole probe data at inlet and exit of the rotor provides the time-resolved data set required. An interaction mechanism is revealed which is responsible for the creation of rotating structures which are fixed in space in the absolute frame of reference at rotor exit. The wakes and secondary flow structures of the nozzle guide vane transform the secondary flow structures at the rotor hub unsteadily. The time-averaged isentropic efficiency distribution at rotor exit is observed to be dominated by flow structures associated with the nozzle guide vane.

Lutoschkin E.,University of Stuttgart | Lutoschkin E.,Institute of Aircraft Propulsion Systems | Rose M.G.,University of Stuttgart | Rose M.G.,Institute of Aircraft Propulsion Systems | And 2 more authors.
Journal of Propulsion and Power | Year: 2013

One method of significantly improving the performance of gas turbine engines is to use the thermodynamically more efficient unsteady combustion with pressure rise. In this work, the feasibility of using the interaction of shock waves with a flame to achieve pressure-gain combustion is investigated. A new analytical model is described. The pressure rise and entropy suppression of a single shock-flame interaction event is predicted for the first time. The model is quasi-one dimensional, with the shock wave planar and the flame laminar premixed. Given known initial flowfield and flame geometry, as well as the incident shock Mach number, the model allows the calculation of a fully defined one-dimensional flowfield that is formed at the end of a single shock-flame interaction event. The analytical model is successfully verified using experimental data on methane-oxygen-argon flames. It is found that a single shock-flame interaction event temporally generates a dramatic increase in pressure compared to isobaric combustion with the same unburned gas conditions. The associated increase in temperature remains at a relatively moderate level. Further, combustion entropy rise is significantly reduced through a single shock-flame interaction event.

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