Rotordynamics
Research focus
The Peer review has evaluated this group as Excellent
The research focus is on the general problems of real rotating machinery tracing an ideal path that: - starts from the mechanical design of the rotor and of the related components, - goes through the set-up of the machine with the related start-up problems, - follows with the condition monitoring of the machine and - eventually ends with the diagnostics and identification of possible faults, with special care to early detection of faults. The general approach is devoted to find out methods and models that are in any case related to real and industrial application and the experimental validation of the theory is always pursued. The use of special designed test-rigs or the use of actual case studies and data coming from the industrial partners usually allows the validation to be made on a sounded basis. It is worth to notice that the test-rigs employed and described hereafter are of a rather big scale, aimed to reproduce the behaviour or real machines or real components. Also the modularity of the test-rigs allows their employment for many purposes, especially for the diagnostics of different types of faults that could affect the rotating machines. Four main research themes are active, in order to cover the topics of the research line: - Simulation of the dynamical behaviour of industrial rotating machines; - Identification and diagnostics of industrial rotating machines; - Condition monitoring of industrial rotating machines; - Dynamical behaviour of rotating machines component like bearing, blades etc. Anyway, the distinction among the themes is more practical than actual, since for instance the accurate modelling of a machine part contributes to a reliable simulation of dynamical behaviour of the entire machine. This can finally be fundamental to define criteria for the condition monitoring as to characterize possible symptoms of faults and the define identification strategies. The research would not be possible without the support of industrial partners that are directly involved in the production of rotating machinery or in its use under economic and efficiency criteria. 26 Considering the first type of partners, they allow the research group to deal with design problems of various sized and types of turbines for power generation (hydraulic, steam and gas) or special high-speed machines like multi-shaft geared compressors, turbo-molecular pumps or atomizers. In all these cases, simulation models and specific software were successfully developed and industrially tested. As regards the second type of partners, they are mainly utilities or final users, in which the rotating machine is a part of the production process, dealing with operating problems. The most relevant aspects to them are: - the most effective condition monitoring of the machine in order to avoid impending failures or malfunction (that in some cases could be potentially catastrophic or very dangerous) or, - when a failure or malfunction occurred, to quickly identify it and to fix if possible. These two requirements support the creation of a service system for condition monitoring, balancing and problem solving on field under customer request, to define specific alarm criteria and to develop model based method for the fault identification, principally in the frequency domain. This method has the advantage that not only the type of the fault is indicated, but also its severity (when relevant, like unbalance or crack depth for instance) and location along the shaft-line (for instance which sealing is too much tightened or badly assembled and rubs when the machine is crossing critical speeds during run-ups or coast-downs) is determined.
Dipartimento di afferenza
Docenti afferenti
Full Professors
Nicolò Bachschmid
Bruno Pizzigoni
Associate Professors
Paolo Pennacchi
Andrea Vania