旋流器关键参数对双旋流冷态流场特性的影响

The non-reaction flow characteristic of a concentric staged double swirl combustor was investigated by particle image velocimetry (PIV) method. The interaction process between main stage and pilot stage swirling flow and the influence mechanism on the flow field in this double swirl combustor were revealed. The effect rules of key parameters such as the pilot stage swirling intensity, the main stage swirling intensity and the air proportion between main stage and pilot stage on the flow field characteristics were obtained. According to the results, the central recirculation zone (CTRZ) cannot be formed in the single pilot stage combustor with reference parameters. With the addition of the main stage strong swirling flow, a CTRZ appears under the interaction of the main stage and the pilot stage swirling flow. In the concentric staged double swirl combustor, the divergence angle and width of the CTRZ, as well as the recirculated mass flow rate increase significantly as the increase of the pilot stage swirling intensity. When the swirl number of the pilot stage swirling flow is greater than 0.6, the size of CTRZ does not change obviously with the increase of swirling intensity. When the main stage is strong swirling flow, the CTRZ changes little with the increase of the main stage swirling intensity. Increasing the swirling intensity will slightly inhibit the development of the CTRZ, but a stable CTRZ can be formed when the swirl number of the main stage swirling flow is 0.723, 1.017 and 1.553, respectively. For the concentric staged double swirl combustor with a weak swirling pilot stage and a strong swirling main stage, the divergence angle and width of the CTRZ, and the recirculated mass flow rate increase noticeably as the increase of the air proportion between main stage and pilot stage.