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Study Of The Technical State Of A Francis Turbine By Rotor Dynamic Simulations

Żółtowski B., Castaneda Heredia L., Barbosa J.

Journal of Polish CIMAC

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2009

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Vol. 4, no 3

113-123

EN

This paper presents a methodology to evaluate the technical state of a Francis turbine by shaft rotor dynamic simulation. There are several rotor dynamic criteria that define the technical state of a turbomachine. To feed the shaft rotor dynamic model this delivers the required information to accomplish the technical assessment. The numerical rotor dynamic model uses as input, the field forces obtained by the fluid-solid interaction analysis undertaken over the blades of the runner. The rotor dynamic numerical simulations allow to determinate the record-in-time of the displacements of any point along the shaft. This information is relevant for diagnosis tasks, because it is possible to decompose it spectrally and to estimate the severity of the vibrations. Comparing the results of the numerical model against those obtained from machines that operates under normal conditions, it is possible to determinate the technical state of the turbomachine. This allows studying the stability of the turbine working on several operation ranges. A Francis turbine is a very complex machine that involves many physical phenomena of different nature. In this way, the hydraulic input forces needed by the rotor dynamic model should not be assumed but calculated directly from the fluid interaction over the turbine structure.

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Multidimensional Monitoring Of Condition – Mmc - Based On The Single Value Decomposition – Svd - Case Study: Railway System

Żółtowski B., Castaneda Heredia L., Betancur Giraldo G.

Journal of Polish CIMAC

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2009

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Vol. 4, no 1

177-187

EN

The multidimensional monitoring of symptoms applied to railway systems allow to detect and locate the sections of the track (straight and curved) that generate the decrement of the safety and comfort of the passengers. It also evaluates the technical state of the rail-vehicle interface. In addition, it allows observing, evaluating, and controlling the reliability and availability of the system. The objective of the study is to propose an alternative to evaluate the condition of the technical state of railway systems from a dynamical point of view which guarantees safety and comfort of the passengers. One looks for diminishing operative costs of maintenance, improving the use of equipment for maintenance tasks of the track, vehicle and auxiliary equipment, optimizing the time of the maintenance personal, the maintenance frequencies (corrective, preventive, etc.). It also aims to identify the variables related to maintenance actions that have a high influence on the technical state of the system. This paper presents the results obtained when applying a modeling of this type to a railway system, being centered mainly in the application of SVD theory to the technical diagnosis of systems.

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Multidimensional Condition Monitoring Of Critical Machines

Żółtowski B., Castaneda Heredia L.

Journal of Polish CIMAC

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2009

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Vol. 4, no 1

169-176

EN

Technical systems are more complex every day as their electronics and mechanics. Technological advances tend to be autonomous in its performance and perform an auto-diagnosis that allows determining an abnormality existence in a component or subsystem and deciding if the system has to be stopped or not. The conventional maintenance does not allow an integrated diagnosis analysis of a system. Among the factors that generated condition can be found a lack of communication between units: bad information management, ignoring relevant information, a lack of a clear monitoring policy and variables tendency.