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| Experimental study on smoke movement and stratification characteristics of tunnel fire under the effect of rainfall and longitudinal ventilation |
| FAN Chuangang1, SHENG Ziqiong1, XIONG Sheng1,2, LUAN Die1*
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1. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China;
2. China Railway No.5 Engineering Group Co., Ltd., Changsha 410117, Hunan, China |
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Abstract In order to cope with the challenge of smoke control in tunnel fire caused by extreme rainfall, a scaled tunnel fire test platform was established based on Froude similarity criterion, and the law of smoke movement, vertical temperature rise and stratification of smoke under the effects of rainfall and longitudinal ventilation were investigated. The results showed that the longitudinal airflow induced by rainfall would hinder the movement of smoke to the rainfall side. As the rainfall intensity increased, the smoke was gradually controlled on the ventilation side, and the thickness of the smoke layer increased. After longitudinal ventilation running, the smoke was affected by both rainfall-induced airflow and forced ventilation airflow. The mixing of hot smoke and cold air intensified under the combined effect of the two airflows, and the thickness of the smoke layer increased. As the longitudinal ventilation velocity continuously increased, the smoke was gradually controlled at the rainfall side, and the smoke settled to the lower space of the tunnel. The increase of rainfall intensity and ventilation velocity destroyed the smoke stratification. When the longitudinal ventilation airflow was equal to the rainfall-induced airflow, the smoke stratification could be maintained stable.
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Published: 28 June 2024
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