Effect of swirl numbers on flow characteristics of a concentric staged lean direct injection combustor
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摘要:
在一种中心分级贫油直喷燃烧室中,对主燃级和预燃级旋流数影响流动特性的规律进行了数值模拟研究。采用了不同参考截面上的旋流数来衡量两级旋流强度。结果表明,预燃级出口旋流数
S v增大导致主回流区最大宽度和最大回流率的增大。使主回流区回流强度显著增强的S v阈值在0.6~0.64之间。主燃级旋流在主回流区涡心上游带动主回流区径向扩张,但主燃级旋流在下游会抑制主回流区,导致回流率的降低。燃级气流通道出口旋流数S n从0.46增大到0.60时流动特性变化较为明显。相对旋流叶片出口截面的旋流数来说,S v和S n可以较好地衡量两级旋流强度等级。Abstract:A numerical investigation was conducted to study the effect of swirl numbers of the main stage and the pilot stage on the flow characteristics of a concentric staged lean direct injection (LDI) combustor. The swirl numbers at different reference cross-sections were used to measure the swirling intensity of the two stages respectively. The results showed that the width and reverse flow rate of the central recirculation zone (CRZ) increased with the increment of
S v (the pilot stage outlet swirl number). TheS v constituting a threshold for significantly enhancing the reverse flow intensity of the CRZ was between 0.60 and 0.64. Upstream the CRZ vortex center, the main stage swirling flow brought about the radial expansion of the CRZ, but downstream it suppressed the CRZ and reduced the reverse flow rate. The flow characteristics changed significantly whenS n (the main stage swirl number at the flow passage outlet) increased from 0.46 to 0.60.S v andS n provided a better measure of the swirling intensity levels of the two stages respectively, relative to the swirl numbers defined at the outlet of the swirler vanes.-
Key words:
- swirl number /
- concentric staged /
- main stage /
- pilot stage /
- flow characteristic /
- central recirculation zone
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表 1 网格方案节点数
Table 1. Nodes quantities of mesh schemes
方案 节点数/106 M1 11.0 M2 7.0 M3 5.9 M4 5.5 -
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