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为解决我国自主研发的某重型燃气轮机DLN燃烧室NOx排放超标问题,基于“小幅改动”,在有限预混空间的前提下,采用一系列结构改进方案与策略,改进中心燃烧区燃料/空气预混均匀性.结果表明,将中心区旋流器移至预混通道上游,可将预混非均匀度从原有的51.8%降至16.7%,而通过调整燃料喷射方向以及喷孔分布规律,可进一步减少非均匀度至10.9%.由此归纳稀相预混燃烧室预混机构的设计策略与要点:一是旋流延长实际预混距离;二是利用旋流产生的强湍流促进燃料的对流扩散;三是调整燃料射流方向或增加导流板,避免管后涡流区对燃料扩散的削弱影响;四是燃料开孔位置大小规律需与来流空气速度分布相匹配.“,”Several optimization strategies and modified premixer structures have been proposed and studied computationally to decrease NOx emissions of the self-developed heavy-duty DLN combustor in China. Premixing uniformity was improved significantly with the adjustments of the fuel-air premixer in the primary zone and the primary holes in the annular zone. The results indicate that the fuel-air non-uniformity of the primary premixer decreases from 51.8% to 16.7% by remounting the swirler upstream the fuel injector and can be further reduced to 10.9% by adjusting the distribution of the fuel injection holes. Four principles for improving the fuel-air premixing can be revealed. First, the premixing distance is lengthened with the swirl flow. Second, the fuel diffusion is enhanced by the increased turbulence intensity in the swirl flow. Third, the fuel injection direction should be optimized to depress the vortex downstream the fuel injector. Forth, the distribution of the fuel injection holes should be rearranged to match the air flowrate distribution.