关键词: 流场；文氏管；回流区；扩张角

Abstract: In order to investigate the effects of venturi on the swirling flow field，four kinds of swirlers which are respectively with no venturi，an inner venturi，an outer sleeve and both venturi and sleeve were studied. The results show that venturi not only can play the role of transition for the rotating jet that makes the velocity circumferential distribution uniform，but also can adjust the velocity magnitude. The existence of venturi can increase the turbulent kinetic energy of the local flow field，but it also may cause the variation of swirl intensity so that the recirculation zone size is changed. The swirler with both venturi and sleeve can provide the stronger swirl flow，so the recirculation zone area is larger. Also it has the wide adjustable range of the combustor chamber inlet pressure，so the structure of flow field is stable，besides，the increment of the sleeve divergence angle can promote the radial expansion of recirculation zone，so the width of recirculation zone increases. When the divergence angle of inner venturi reaches the critical angle of 57°，the recirculation zone in the case of the swirler with both venture and sleeve splits into two independent parts.

Key words: Flow field；Venturi；Recirculation zone；Divergence angle