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使用PIV实验和CFD数值模拟的方法研究多个双级旋流器和单个双级旋流器下游的冷态流场,对比分析两种情况下,速度场分布、漩涡结构和涡量的变化规律,获得边界条件对双级旋流器下游漩涡结构的影响规律。PIV实验与CFD数值模拟结果在中心漩涡结构和涡量的变化规律上吻合得较好;单个旋流器情况下,由于旋流器和壁面之间的相互作用形成了两对角涡,多个旋流器情况下,由于旋流器旋流之间的相互作用而形成了一个旋流器边界区域漩涡(边界涡);单个旋流器情况下的中心漩涡涡强在主燃孔射流之前始终低于多个旋流器情况,其中,距离旋流器出口10mm处,数值模拟结果显示单个旋流器中心漩涡涡量是多个旋流器的92.4%,而PIV实验结果显示该值为90.0%;单个旋流器情况下主燃孔射流对中心漩涡的加强作用较多个旋流器更加显著。正是由于不同边界条件下,外围流体处的漩涡结构不同导致了中心漩涡涡量变化规律不同。
The PIV experiment and CFD numerical simulation are used to study the flow field in the cold state downstream of a plurality of two-stage cyclones and a single two-stage cyclone. The variation of the velocity field, the vortex structure and the vorticity are compared and analyzed under the two conditions The influence of the boundary conditions on the vortex structure downstream of the two-stage cyclone was obtained. Experimental PIV and CFD simulation results coincided well with the variation in swirl and vorticity of the central structure; in the case of a single swirler, the swirler due to the interaction between the wall surface and the two pairs of angle of the scroll, a plurality of In the case of a cyclone, a cyclone boundary region vortex (boundary vortex) is formed due to the interaction between cyclone swirl flows; the central vortex vortex intensity in the case of a single cyclone is always before the main bore jet Which is lower than that of multiple cyclones. The numerical simulation results show that the single vortex center vortex vortex is 92.4% of the multiple cyclones at a distance of 10mm from the outlet of the cyclone, while the PIV experimental results show that the vortex vortex is 90.0 %. In the case of a single cyclone, the enhancement effect of the main hole jet on the central vortex is more significant than that of the multiple cyclone. It is because of the different boundary conditions, the vortex structure at the periphery of the fluid leads to the variation of the eddy vorticity in the center.