Research on the flow characteristics of the axial inlet section in a rotor-stator cavity with inward throughflow

Abstract

The inlet for the rotor-stator cavity with inward flow is typically a high-swirl flow introduced at the centrifugal compressor outlet. When this flow enters and flows through the axial inlet section and entrance bend, there can be significant changes in the flow parameters, which can affect the overall flow characteristics inside the cavity. The emphasis of this study is on the airflow mixing process at the bend section. By combining experimental study on the rotor-stator cavity with numerical simulations, the study investigates the internal flow characteristics of the cavity’s inlet section under different flow coefficients $C_w$ and rotational Reynolds numbers $R{e}_{\phi }$ , with inlet swirl ratios ${\beta }_0$ ranging from 0 to 0.7 and turbulence coefficients ${\lambda }_T$ between 0 and 0.55. Under different operating conditions, the internal flow field in the cavity conforms to the Batchelor flow pattern. The study found that the distribution of the flow field at the inlet section is jointly determined by the non-dimensional parameters ${\beta }_0$ and ${\lambda }_T$ . Furthermore, a physical model was established, which combined with the process of mixing of the airflow at the bend section of the inlet, and formed an accurate description of the corresponding relationship between the mixing airflow swirl ratio ${\beta }_{\mathrm{d}}$ and ${\beta }_0$ , ${\lambda }_T$ . Based on this, an empirical correlation was developed with a correlation coefficient of 0.998. This empirical correlation can provide a theoretical correction for the flow field distribution of the axial inlet section in a rotor-stator cavity.