...Paolo Silvestri; Silvia Marelli; Vittorio Usai Centrifugal compressors play a critical role in various industrial applications, and understanding their operational behavior, especially during surge conditions, is essential for enhancing efficiency and reliability. This study investigates surge...

... possible operating range. Flow instabilities in the form of rotating stall and surge are therefore phenomena that must be accurately predicted early in the design process. Unsteady full-annulus computational fluid dynamics (CFD) can be used to get accurate information about the onset of instabilities...

... vibro-acoustic characterization is conducted at on-design and stable operation. Afterwards, some surge transients are obtained by progressively closing some valves in plant feeding lines, and meanwhile vibro-acoustic signals are acquired at relevant plant locations to characterize system response just...

... lead to severe vibrations related to fluid-dynamic instabilities during part load operating conditions. In particular, surge strongly limits centrifugal compressors stable operating region when moving toward low mass flow rates due to a change in system working point. Therefore, compressor dynamic...

... a spike-wave precursor to surge; at 90% corrected speed, the compressor has undergone the process of modal wave precursor, spike-wave precursor, and surge. Further, at 70% and 90% corrected speed, a classic surge occurred with surge frequencies of 11.91 Hz and 9.59 Hz, respectively. Through the analysis...

...Paolo Silvestri; Federico Reggio; Carlo Alberto Niccolini Marmont Du Haut Champ; Mario Luigi Ferrari; Aristide Fausto Massardo Dynamic compressors operating region is mainly constrained by fluid-dynamic instabilities occurring at low mass flowrate conditions, such as surge and rotating stall...

... layouts as fuel cell systems. Instability phenomena limit the operating range of the whole compressor system, especially during fast transients. The target is therefore to extend the minimum flow limit in order to improve the operability of each unit while avoiding compressor surge operation...

... instability, as they are not stable. They believe that there was no influence between the individual blade-to-blade impeller channels, due to their relatively large pitch. However, if the operating condition had been selected closer to the surge line, a rotating stall would have likely occurred...

... flow phenomena. Compressors are known to be affected by unstable flow conditions appearing at low mass flowrate conditions. The best known and most dangerous phenomenon is surge, which is a global instability affecting the entire impeller and regions upstream and downstream from it. A list...

... prior to deep surge and introduces a new approach to identify these disturbances using nonlinear feature extraction algorithms including phase-reconstruction of time-series signals and evaluation of a parameter called approximate entropy. To the best of our knowledge, this is the first time approximate...

... to rotating stall and surge operations. This analysis was carried out to extend the knowledge about these risk conditions: the systems equipped with large volume size connected to the machine present critical issues related to surge and stall prevention, especially during transient operations toward low mass...

... Measurement techniques Compressor stall Surge Centrifugal pumps Operability After interpreting the results of the experimental study, the torsional stiffness of this specific coupling was determined to be 6.67 × 10 8 in.·lb/rad. This value was calculated using the torsional windup from indicators...

... . Manuscript received February 14, 2014; final manuscript received February 21, 2014; published online March 21, 2014. Editor: David Wisler. 14 02 2014 21 02 2014 A hybrid control system has been proposed for compressor surge, which combines the active method with the passive method...