Study on the maximum temperature and temperature decay in single-side centralized smoke exhaust tunnel fires

Abstract In order to explore the temperature distribution in a single-side centralized smoke exhaust tunnel (only one side of the exhaust duct is fitted with a smoke exhaust fan, while the other side of the exhaust duct is closed), a 60 m long model tunnel was established to study the temperature of tunnel vault with different smoke exhaust air volumes and heat release rate (HRR). The results show that the maximum temperature first increases and then decreases with the increase of the exhaust air volume under the same HRR. When the exhaust air volume is more than 0.90 m³/s, the exhaust air volume has little effect on the maximum temperature. The smoke exhaust volume mainly affects the longitudinal temperature distribution of tunnel upstream of the fire source, and the temperature of the smoke decreases rapidly after passing through the smoke vent. Under different exhaust air volume, the vault temperature at the upstream outside the smoke vent is less than 80 °C, and the vault temperature at the downstream is less than 65 °C. The existing prediction models of temperature decay cannot predict the temperature decay of single-side centralized smoke exhaust tunnel. Based on the experimental results, the temperature decay model of single-side centralized smoke exhaust tunnel was deduced. The temperature decay laws of the upstream and downstream in a single-side centralized smoke exhaust tunnel are different, and the error between the proposed temperature decay prediction model and the experimental results is less than 20%.