Study on the Length of Smoke Backlayering of Double-Source Fire in Tunnels

In order to predict the smoke backlayering length of double-source fire in tunnels, this paper deduced the dimensional expressions for smoke backlayering length by theoretical analysis and proposed a prediction formula for smoke backlayering length in single-source fire on the basis of the Fire Dynamics Simulator. Based on the results, the paper proposed a method for studying the smoke backlayering length of double-source fire in the tunnel. By introducing the fire power influence coefficient alpha and the distance influence coefficient beta, the formula for predicting smoke backlayering length in single-source fire was revised to obtain a new formula for predicting the smoke backlayering length of double-source fire. By comparing the formula prediction value with the simulation value, it is found that the prediction formula is almost accurate. This study will be helpful for understanding the multisource tunnel fire and predicting the smoke backlayering length of double-source fire in tunnels, which can provide guidance for tunnel fire rescue.