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论文类型：期刊论文

发表时间：2016-01-01

发表刊物：ENGINEERING APPLICATIONS OF COMPUTATIONAL FLUID MECHANICS

收录刊物：SCIE

卷号：10

期号：1

页面范围：565-577

ISSN号：1994-2060

关键字：Unshrouded centrifugal impeller; diffuser performance; impeller-diffuser interaction; unsteady simulation; frequency spectrum analysis

摘要：The unsteady phenomenon abounds in centrifugal compressors and significantly affects the compressor performance. In this paper, unsteady simulations are carried out to investigate the aerodynamic performance of a process-unshrouded centrifugal compressor and the unsteady mechanism in the vaned diffuser. The predicted stage performance and pressure fluctuations at some locations are in good agreement with experimental data. The predicted main pressure fluctuation frequency spectrums at the diffuser inlet and outlet are consistent with the measured results. The results indicate that at the inlet of the diffuser there are two pressure peaks in a passage cycle. The higher pressure peak relates to the impeller wake and the lower peak is connected with the vortex generated at the diffuser's leading edge. With a decrease in the mass flow coefficient, the vortex core region becomes larger and the lower pressure peak becomes more pronounced. The change in circumferential flow angle at the diffuser inlet is mainly responsible for the unsteadiness in the diffuser flow field, which in turn affects the inlet incidence of the diffuser vane and the vane loading distributions.