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| Study on the effect of makeup air supplementation on fire smoke control in subway tunnel |
| LEI Wenjun1, GUO Lili1, ZHAO Xuming1, TAI Chuanmin1, QI Yue2
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1. School of Thermal Engineering, Shandong Jianzhu University, Jinan 250101, Shandong, China;
2. Moon Environment Technology Co., Ltd., Yantai 264002, Shandong, China |
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Abstract To address the issues of excessive air volume and insufficient targeting effectiveness in traditional subway tunnel make-up air systems, a novel composite ventilation method was proposed. This approach integrated side-supply in the breathing zone with bottom-supply ventilation based on occupant evacuation behavior patterns, with the objective of investigating its effectiveness in controlling smoke dispersion in evacuation passages. A physical model of a metro tunnel section was constructed using numerical simulation. Comparative analysis was conducted on the distribution patterns of CO mass concentration, temperature, and visibility in evacuation pathways under four distinct ventilation conditions: natural air replenishment, breathing-zone lateral air supply, bottom air supply, and combined ventilation modes.The study found that natural make-up air had the worst effect on controlling fire smoke in the evacuation channel, with visibility, CO mass concentration, and temperature all failing to meet personnel evacuation requirements.Breathing zone side-feeding make-up air could control the CO mass concentration in the evacuation channel below 62 mg/m3, but the mixing of make-up air and smoke caused the average temperature in the evacuation channel to reach 227 ℃, which did not satisfy the requirements for safe personnel evacuation. For bottom make-up air, the average temperature in the evacuation channel exceeded 300 ℃, and the average CO mass concentration was 100 mg/m3, both higher than the safety parameters required for personnel evacuation. When the combined make-up air of breathing zone side-feeding and bottom-feeding was applied, with the air volume ratio of side-feeding to bottom-feeding being 6∶1 and the corresponding wind speeds being 1.8 m/s and 0.3 m/s respectively, the CO mass concentration in the evacuation channel was 34.6 mg/m3, the temperature was 59.2 ℃, and the visibility was 18.6 m—all meeting the standards for safe personnel evacuation. The combined make-up air method of side-feeding in the breathing zone and bottom-feeding can effectively control fire smoke in metro tunnel evacuation channels, providing a theoretical basis for precise make-up air design in underground spaces aimed at ensuring personnel safety.
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Published: 18 June 2025
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