The Influence of Dump Gap on External Combustor Aerodynamics at High Fuel Injector Flow Rates
The Influence of Dump Gap on External Combustor Aerodynamics at High Fuel Injector Flow Rates
复制标题
高喷油器流量下排放间隙对外燃室空气动力学的影响
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. McGuirk
中科院分区：
文献类型：
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作者：
A. Walker;J. F. Carrotte;J. McGuirk
对减少燃气轮机的燃料燃烧以及CO 2 排放的需求不断增加，需要有效的扩散以减少燃烧器中的系统压力损失。然而，预扩散器和燃烧器之间的相互作用会对扩散器性能产生重大影响。例如，已经显示了使用传统设计准则设置的转储间隙处增加喷油器流量的结果（Walker, A. D.、Carrotte, J. F. 和 McGuirk, J. J.，2007 年。“精益模块燃烧器中的压缩机/扩散器/燃烧器空气动力相互作用”，ASME Turbo Expo 2007-Power for Land Sea and Air，论文号 GT2007-27872），以介绍一个 燃油喷射器和上游部件之间的不稳定相互作用。本文重点研究排空间隙增加的影响。采用 0.8、1.2 和 1.6 的转储间隙比，每次测试均使用相同的入口导叶、压缩机转子、集成出口导叶 (OGV)/预扩散器和转储几何结构。进入燃烧室整流罩的压缩机流出物的流量分数被设置为代表稀薄燃烧室（50-70%）。测量是在全环形装置上进行的，使用带有计量罩和内/外环流的通用火焰管。结果表明，在固定整流罩流量的情况下，随着排放间隙的增加，部件相互作用会减少。当转储间隙比为 0.8 时，火焰管的接近度会影响预扩散器，从而提供有益的堵塞效果。然而，如果增加到 1.2，这种有益效果就会减弱，预扩散器流量也会恶化。当进一步增加到 1.6 时，预扩散器显示出强烈的分离迹象。因此，在贫油模块喷射器可能需要的排放间隙处，预扩散器不太可能受到火焰管堵塞的有益影响；设计中必须考虑到这一点。此外，在较小的转储间隙和较高的整流罩流量分数的情况下，整流罩流量的周向变化可能会向上游流动并导致 OGV/转子受力。在较大的转储间隙下，周向变化不会渗透到 OGV 上游，并且转子不受影响。最佳的转储间隙和预扩散器设计可实现从转子到进给环的最佳整体空气动力系统性能，这是充分利用上游阻塞效应和最小化任何 3D 上游强迫之间的折衷。
The increasing demand to reduce fuel burn, hence CO 2 emissions, from the gas turbine requires efficient diffusion to reduce the system pressure loss in the combustor. However, interactions between prediffuser and combustor can have a significant effect on diffuser performance. For example, the consequence of increased fuel injector flow at a dump gap set using conventional design guidelines has been shown (Walker, A. D., Carrotte, J. F., and McGuirk, J. J., 2007. "Compressor/Diffuser/Combustor Aerodynamic Interactions in Lean Module Combustors," ASME Turbo Expo 2007-Power for Land Sea and Air, Paper No. GT2007-27872) to introduce a destabilizing interaction between fuel injector and upstream components. The present paper concentrates on examining the effects of increased dump gap. Dump gap ratios of 0.8, 1.2, and 1.6 were employed, with each test utilizing the same inlet guide vane, compressor rotor, integrated outlet guide vane (OGV)/ prediffuser, and dump geometry. The flow fraction of compressor efflux entering the combustor cowl was set to be representative of lean combustors (50-70%). Measurements were made on a fully annular rig using a generic flame tube with metered cowl and inner/outer annulus flows. The results demonstrate that, with fixed cowl flow, as the dump gap increases, component interactions decrease. At a dump gap ratio of 0.8, the proximity of the flame tube influences the prediffuser providing a beneficial blockage effect. However, if increased to 1.2, this beneficial effect is weakened and the prediffuser flow deteriorates. With further increase to 1.6, the prediffuser shows strong evidence of separation. Hence, at the dump gaps probably required for lean module injectors, it is unlikely the prediffuser will be influenced beneficially by the flame tube blockage; this must be taken into account in the design. Furthermore, with small dump gaps and high cowl flow fraction, the circumferential variation in cowl flow can feed upstream and cause OGV/ rotor forcing. At larger dump gaps, the circumferential variation does not penetrate upstream to the OGV, and the rotor is unaffected. The optimum dump gap and prediffuser design for best overall aerodynamic system performance from rotor through to feed annuli is a compromise between taking maximum advantage of upstream blockage effects and minimizing any 3D upstream forcing.