Parametric Assessment of a Surge Severity Coefficient

Centrifugal compressors are often used in industrial applications in order to complete different types of processes. Despite their large tolerance to process fluctuations they cannot operate beyond their stability limit, otherwise surge occurs. Surge is dangerous, not only because it leads to unstable operating conditions, but also because it causes axial force fatigue cycles which can severely damage the compressor and its close clearance components. This paper exploits a lumped parameter dynamic model to study a surge severity coefficient by means of a sensitivity analysis and previous experimental tests results, thus identifying the geometric dimensions and thermodynamic factors which significantly affect surge severity, and thus the risk of damage. This paper represents an attempt to evaluate the reliability of a surge severity coefficient which potentially indicates if, after a surge event, an inspection or maintenance are required.