The disk cavity of the rotor-stator system is one of important parts of the aero-engine internal air system. After receiving the upstream airflow, a series of complex flow structures take place in the cavity, and then the airflow is exported to the downstream chamber. The rotating speed of airflow determines the relative velocity between the airflow and the rotating assembly, which affects the windage of the rotating assembly. So the maintaining characteristic for swirling flow of the rotor-stator cavity will affect the windage of the rotating assembly in the cavity, and the exporting characteristic for swirling flow of the rotor-stator cavity will affect the windage of the rotating assembly in the downstream chamber. Therefore, the maintaining characteristic and the exporting characteristic for swirling flow have an important influence on the windage of the whole internal air system. Dual-inlet rotor-stator disk cavity is a common structure of aero-engine. But there are few reports about the flow structure in the dual-inlet rotor-stator disk cavity in the open literature. Unlike the simple rotor-stator cavity, the diversities of inflow distributions in the dual-inlet rotor-stator cavity make the maintaining characteristic and the exporting characteristic for swirling flow more complicated. In this paper, the influence of inflow distributions on the maintaining characteristic and the exporting characteristic for swirling flow is investigated by numerical simulation, aiming at the interaction between the centripetal inflow and the centrifugal inflow in the dual-inlet rotor-stator cavity. The two inlet are located at the hub and rim respectively and the outlet is on the stationary assembly. The results show that the fluid from the hub inlet flows centrifugally along the rotating disk and the fluid from the rim inlet flows centripetally along the stationary disk. There are two flow regions in the upper and lower part of the rotor-stator cavity respectively, and there is a clockwise rotating vortex in each flow region. The upper part of the cavity is dominated by viscous force and the lower part of the cavity is dominated by inertial force. In order to quantify the rotational capacity of the airflow, the angular momentum coefficient is defined. Under different inflow distribution ratios, the sizes of the dominant region of the two vortices in the cavity get varied, which results in the variation of the maintaining characteristic and the exporting characteristic for swirling flow. And the torque of rotating disk changes accordingly. Reasonable arrangement of inflow distributions can significantly promote swirling flow and suppress the windage loss. It is also found that the inflow distributions has the same effect on the maintaining characteristic and the exporting characteristic for swirling flow under different rotational Reynolds numbers and different throughflow coefficients, but the capacity of maintaining and exporting swirling flow are quite different.


Influence of Inflow Distributions on Swirling Flow in Rotor-Stator Cavity With Centripetal and Centrifugal Superposed Flow

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

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