Study on Multiple Air-Opening Ventilation Characteristics and Pollutant Control for the Tunnel with Decentralized Exhaust under Jet Pressurization
(1. Zhejiang Institute of Mechanical & Electrical Engineering Co., Ltd., Hangzhou 310051; 2. Center for Balance Architecture, Zhejiang University, Hangzhou 310007; 3. Key Laboratory of Offshore Geotechnical and Material Engineering of Zhejiang Province, Zhejiang University, Hangzhou 310058; 4. Zhejiang University Zhongyuan Institute, Hangzhou 310014)
Abstract：
In order to reveal the influence of the sudden change of tunnel pressure caused by air intake/exhaust of the top exhaust outlet on the multiple air opening ventilation characteristics of the tunnel with decentralized exhaust,the computational fluid dynamics method was used to simulate the air intake and exhaust laws of grouped top exhaust outlets under the action of jet pressurization. The results show that air exhaust/intake of the top exhaust outlet will cause a sudden increase/decrease of the local pressure in the tunnel, and the ventilation characteristics of multiple top exhaust outlets in the tunnel with decentralized exhaust are affected together by jet pressurization, resistance along the way and sudden pressure change caused by the ventilation at the air opening. The interval between air openings is an important factor that affects the air volume change of multiple air openings. For the exhaust type air opening, when the interval between air openings is small, the sudden pressure increase generated by the exhaust at the upstream air opening will exceed the loss along the way between air openings, and the air exhaust volume at the downstream air opening will increase along the way due to the rise of the static pressure. When the interval between air openings is large, the sudden increase of pressure will not be enough to overcome the loss along the way between air openings, and the exhaust air volume of downstream air openings will decrease along the way, or even change into air intake; For the intake type air opening, the air intake volume of the air opening will increase along the way under the superposition of the sudden pressure drop caused by the air intake and the loss along the tunnel. Compared with starting methods of other fans, the fan is started to be in the staggered position relative to the air opening group,which is a more efficient ventilation control method for the tunnel with decentralized exhaust, and it can minimize the extreme concentration of pollutants in the tunnel.
LI Bao1,
2 WU Kaijie2,
3 XIONG Jing1 SHEN Hang1 WENG Jiajun2 etc
.Study on Multiple Air-Opening Ventilation Characteristics and Pollutant Control for the Tunnel with Decentralized Exhaust under Jet Pressurization[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(1): 159-167
2023, Vol. 60 