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. Surge is a phenomenon that
leads to significant pressure and mass flow rate fluctuations.
Compressors can be damaged from surge instability, which
results in vibrations and thermal stress. This study investigates
surge transitions in centrifugal compressors by employing a
comprehensive approach that integrates dynamic mass flow rate
and pressure measurements using anemometric fiber film probes
and high frequency piezoresistive pressure transducers together
with dynamic structural response data.
To gain insight into the transition from the stable to the
unstable region of the compressor, an extensive experimental
analysis on a centrifugal compressor was conducted at the
University of Genoa test bench for components of propulsion system. The activity involves measurements used to characterize and identify the behavior of the compressor in correspondence of surge inception conditions.
Measurements were conducted for different corrected rotational speed level stable and unstable operating points on the compressor characteristic curves including incipient and deep surge conditions were acquired, considering also different outlet circuit lines.
Pressure transducers and anemometric film probes were employed to gather data on the compressor’s fluid dynamics. Frequency and time-frequency data analysis techniques have been employed to examine the inflow pressure and the anemometric signal. The purpose is to identify their characteristics and define the compressor operation as stable or unstable. Synchronous averages, applied in the time domain, have proven to be effective for detecting incipient surge conditions jointly with variance computation. Additionally, statistical techniques, such as variance and spectral kurtosis, have been utilized for the detection in signals with strong additive noise of transient and non-deterministic contents may rise approaching instable conditions.
A method for system identifying in deep surge is introduced, particularly a correlation between the compressor circuit geometries and the operating condition of the turbocharger is proposed. This approach enhances the diagnostic capability of the monitoring system by providing a better knowledge of surge occurrence. The paper is aimed to provide information for the development of advanced control strategies and predictive maintenance protocols to mitigate surge-related issues and improve the overall performance and reliability of centrifugal compressors.
