Abstract: In order to study the effects of the airflow split on the flow characteristics and downstream flow field of double-axial swirler, experimental investigations were conducted by flow characteristics experimental system and PIV. The influences of air split on the flow rate, discharge coefficient and downstream flow field were obtained. The experimental results indicated that increasing the frontal area, discharge coefficient of the primary swirler decreases, while the discharge coefficient of the secondary swirler remains constant. When A₁/A₂<0.75, the discharge coefficient of the primary swirler is greater than that of the secondary swirler. When A₁/A₂>0.75, the discharge coefficient of the secondary swirler is greater than that of the primary swirler. Increasing the airflow ratio of the primary swirler to the secondary swirler，recircling flow velocity of the central toroidal recirculation zone （CTRZ） decreases, the axial velocity and radial velocity of the swirling flow divergent angle zone decrease, the size of the CTRZ decreases. The axial velocity profiles along centerline increases as the airflow ratio initially and decreases afterwards.

Key words: Double-axial swirler;Airflow split;Flow characteristics;Downstream flow field;Experimental investigation

摘要： 为研究一、二级气量分配对双级轴向旋流器流量特性及出口流场的影响，对不同气量分配的双级轴向旋流器开展了流量特性试验和PIV试验研究，获得了气量分配对旋流器流量、流量系数和出口流场的影响规律。试验结果表明：相同空气压差下，随着节流面积的增大，一级流量系数减小，二级流量系数变化不显著。一、二级面积比小于0.75时，一级流量系数大于二级流量系数；面积比大于0.75时，二级流量系数大于一级流量系数。随着一、二级气量比的增大，旋流器出口下游回流区速度降低，回流区外侧扩张锥面轴向速度和径向速度均降低，中心回流区变小。中心线轴向速度随气量比的增大先增后减。

关键词: 双级轴向旋流器;气量分配;流量特性;出口流场;试验研究