Experimental Investigation of Elbow-induced Intake Distortion and its Impact on Centrifugal Compressor Performance

The intake of centrifugal compressors through elbow pipes causes inlet flow field distortion, impacting overall compressor performance. To clarify the underlying mechanisms, an experimental investigation was conducted on a centrifugal compressor, and the inlet flow field was characterized using particle image velocimetry and Phase Doppler Anemometry (PDA). The results show that elbow inlet pipes cause significant performance deterioration compared with straight inlet pipes. Near the choke point, the compressor pressure ratio drops by ۱۶.۱۹% and the efficiency falls by ۲۷.۰۸%. This performance decline is primarily attributed to severe flow field distortion. Specifically, two distinct counter-rotating main vortex cores appear in the radial cross-section of elbow inlet pipes—the upper left vortex rotates counter-clockwise while the lower left vortex rotates clockwise—substantially disturbing flow uniformity. Moreover, circumferential static pressure non-uniformity intensifies with increasing flow rate. Further analysis reveals that the pressure ratio and efficiency change rates correlate strongly and negatively with the circumferential velocity uniformity index, but weakly with the radial velocity uniformity index. These findings provide a crucial experimental foundation and theoretical guidance for optimizing centrifugal compressors with elbow inlet pipes.

کلیدواژه ها:

Centrifugal compressor ، Elbow inlet pipe ، Flow distortion ، field measurement ، Performance deterioration