Effect of rotational direction of triple-swirler on cold flow characteristics of a model combustor

Abstract

Triple-swirler plays an important role for aero-engine combustors to achieve high temperature rise. In this paper, experimental investigations were carried out to explore the effect of triple-swirler rotational direction on swirling flow field in atmospheric condition. Two-dimensional-planar particle image velocimetry measurements show that the central toroidal recirculation zone (CTRZ) formation is significantly affected by the swirler rotational direction combinations: an obvious CTRZ can be formed by the triple-swirler with co-rotating intermediate swirler and outer swirler, while a much smaller CTRZ was obtained by the triple-swirler with a counter-rotating intermediate and outer swirler. Furthermore, the swirl level of the mixed flow is significantly affected by the rotational direction combination, and the integrated swirl numbers were calculated to help evaluating the swirl level generated by triple-swirlers. The rotational direction combination plays a key role on the tangential velocity distribution. The tangential velocity distribution is not only closely related to rotational direction, but also the swirl number combination and mass proportion of each swirler in a triple-swirler.