针对金属矿深部长距离掘进巷采用串联式贴附射流通风，存在风质衰减显著、污染易循环累积等问题，本研究采用CFD数值模拟方法，构建串联通风模式下流场及湿-热-尘多维污染物扩散模型，深入剖析流场结构及污染物扩散规律，提出首段大直径风筒调质+次段风筒局部增压的双级变径式通风优化设计，并对该设计的关键参数(筒径比λ、串联间距H)进行进一步寻优，最终通过某金属矿深井长距离巷道试验验证。结果表明，串联式贴附射流流场可分为喷射发展区、偏转气流区、再循环区和稳定回流区四个部分。再循环区内形成的强剪切涡旋结构使巷道内温-尘综合污染物在此聚集盘旋，是造成二次污染的关键原因。双级变径通风模式的污染物排除能力在λ=0.75, 0.80, 0.85, 1.00四个实验组内，随串联间距H (0.5 m≤H≤1.0 m)减小均呈现先增强后减弱的特征，同时在同一H条件下，随λ减小呈现相似的先增后减趋势。在当前研究区间内存在最优工况条件(λ=0.80, H=1.0 m)，相较于优化前，工作区呼吸性粉尘最大浓度降至1 mg/m3所需的排尘时间缩短45.8%，连接区缩短35.4%，有效提升了串联通风模式下污染物排放能力。

For long-distance deep mining in metal mines, the adoption of tandem attached jet ventilation leads to significant air quality attenuation and easy cyclic accumulation of pollutants. This study employs CFD numerical simulation methods to construct a multidimensional pollutant diffusion model of airflow and wet-thermal-dust under tandem ventilation conditions. After in-depth analysis of airflow structure and pollutant diffusion patterns, a dual-stage variable diameter ventilation optimization design is proposed, featuring large-diameter air duct conditioning in the first section and localized pressurization in the secondary section. Key parameters (duct diameter ratio λ and tandem spacing H) are further optimized. Experimental validation in a deep metal mine long-distance roadway confirmed the following findings: the tandem attached jet airflow can be divided into four zones: the jet development zone, deflected airflow zone, recirculation zone, and stable backflow zone. The strong shear vortex structure formed in the recirculation zone causes the aggregation and swirling of comprehensive thermal-dust pollutants in the roadway, which is the key cause of secondary pollution. Under the dual-stage variable diameter ventilation mode, the pollutant removal capacity in four experimental groups (λ=0.75, 0.80, 0.85, 1.00) initially strengthens and then weakens as tandem spacing H (0.5 m≤H≤1.0 m) decreases. Under the same H condition, a similar trend of initial increase followed by decrease is observed as λ decreases. Within the current research range, an optimal operating condition (λ=0.80, H=1.0 m) exists. Compared to pre-optimization, post-optimization results show a 45.8% shortening of the time to reduce breathable dust concentration to 1 mg/m3 in the working zone, along with a 35.4% reduction in the connecting zone. This effectively enhances pollutant emission capacity under tandem ventilation conditions.