直流孔旋流器的结构设计与流场特性研究

Structural design and flow field characteristics of direct-hole cyclone

为改善导叶式旋流器的气流旋进涡核运动和微弱旋流对航空发动机油气混合体稳定燃烧产生的较大影响,优化燃烧室的燃烧效率和稳定性,设计了一种双向变截面直流孔型旋流器。在旋流器第4层减速板后设计3主3辅共6个错位均布的燃油喷嘴,以此产生均匀的燃油油雾参与流场仿真。以气流速度210 m/s、压力28 kPa和流量1.7 kg/s为入口条件,通过流场仿真,分别计算了单一气流和油气混合工况下,流经旋流器的气流速度、流量变化和油气分布状态。与导叶式旋流器相比,经直流孔旋流器减速的气流稳定性更好,形成了低压回流区的流场状态,空气质量流量在旋流器平稳运行后保持相对稳定,随速度均匀变化,且在特定速度下保持着相对较高的稳定状态。直流孔旋流器在燃油预混方面表现出较高的油气混合均匀度,油气在旋流器末端均匀分布,流线规整均匀,流场中央及周边区域未见绕轴微弱旋进油气混合气。

In order to improve the influence of the vortex nucleus and the weak cyclonic flow,and to opti⁃mize the combustion efficiency and stability of the combustor,a bi-directional variable cross-section direct current orifice type cyclone was designed.Three main and three auxiliary fuel nozzles were designed after the 4th reduction plate to produce a uniform fuel mist to participate in the flow field simulation.The airflow velocity,flow rate variation,and oil and gas distribution states under single airflow and oil and gas mixing conditions were calculated by flow field simulation with the airflow velocity of 210 m/s,pressure of 28 kPa and inlet flow rate of 1.7 kg/s as the inlet conditions.Compared with the guide vane cyclone,the airflow de⁃celerated by the direct current orifice cyclone has good stability,forming the flow field state of low-pressure reflux area.The direct current bore cyclone shows high oil and gas mixing uniformity in fuel premixing,the oil and gas is evenly distributed at the end of the cyclone,the flow line is regular and uniform,and the oil and gas mixture is not weakly spun in around the axis in the central and surrounding areas of the flow field.