The flow and heat transfer characteristics of a pre-swirl rotor-stator system with three pre-swirl angles(0°
15°and 30°) was analyzed experimentally.The maximum outflow rate from central hole was 10% of total outflow.The experimental results show that
when the central outflow rate is much less than total outflow
it has small effects on average Nu number of rotor surface
without considering the effects of central outflow on heat transfer.An increase of central outflow rate results in quick drop of static pressure near the center of stator.The rotating speed of rotor has different influence on static pressure of stator surface at different pre-swirl nozzles.