【摘要】 H/J级重型燃机新型余热锅炉(heatrecoverysteam generator,HRSG)内在结构复杂性将会降低选择性催化还原(selective catalytic reduction,SCR)系统前流场均匀性，为实现全负荷工况下的高效脱硝，本研究旨在优化不同负荷下余热锅炉内烟气流动特性。采用计算流体力学(computational fluid dynamics,CFD)方法，系统研究100%、75%、50%和30%负荷余热锅炉内的烟气流动特性；揭示凹陷结构诱导涡流的生成机制，并提出“整流格栅+分区喷氨”的复合优化策略。结果显示，负荷提高使涡流强度增强，烟气流动均匀性更加恶化。50%负荷下，余热锅炉较高的进气温度和结构引发换热管束局部存在±25 K局部温差。优化后，整流格栅有效消除了涡流，使速度标准偏系数降低至3.36%；分区喷氨策略使氨气浓度标准偏差系数降低3.31%，同时降低喷氨量减少氨逃逸。所提方法在不改HRSG结构条件下，创造了有利于脱硝反应的条件，解决了变负荷与流动均匀性的矛盾，可为新型HRSG设计提供一定理论依据。更多还原

【Abstract】 The inherent structural complexity of H/J-class heavy-duty gas turbine-based novel heat recovery steam generator(HRSG) will reduce flow field uniformity upstream of the selective catalytic reduction(SCR) system. To achieve efficient denitrification under full-load operations, this study aims to optimize the flue gas flow characteristics within the HRSG under varying load conditions. Through computational fluid dynamics(CFD) modeling, this study investigates flue gas flow field characteristics in an HRSG under four load levels(100%, 75%, 50%, and 30% of the rated load). The research reveals the vortex generation mechanism induced by recessed structures and proposes a composite optimization strategy combining “flow straightening grid and zoned ammonia injection”. The findings reveal that higher operating loads lead to enhanced vortex intensity and aggravated deterioration of flue gas flow homogeneity. At 50% load, the HRSG exhibits ±25 K localized temperature variations in heat exchange tube bundles due to high flue gas inlet temperatures and entry geometric factors. After optimization, the flow straightening grid effectively eliminated vortex, reducing the velocity coefficient of variation(CV) to 3.36%. The zoned ammonia injection strategy decreases the CV of NH3concentration by 3.31% while reducing ammonia consumption and ammonia slip. The proposed method creates favorable conditions for denitrification reactions without structural modifications to the HRSG itself, effectively resolving the inherent conflict between load variations and flow uniformity.This approach provides theoretical foundations for next-generation HRSG design.更多还原