Temperature profile of fire-induced smoke in node area of a full-scale mine shaft tunnel under natural ventilation

This paper investigated ceiling temperature profile of fire-induce smoke in the common node area of tunnels. The experiments were conducted in a full-scale mine shaft tunnel under natural ventilation with the node area consisted of a straight tunnel and two curved tunnels. Maximum ceiling temperature above the fire, transverse ceiling temperature along the elliptic ceiling and longitudinal ceiling temperature along the main and branch tunnels were measured by K-type thermocouples or thermometric cable. Dimensionless expression for predicting transverse and longitudinal ceiling temperature distribution was proposed based on previous models. Normalized expression of longitudinal temperature decay coefficients were correlated as well by taking the heat release rate and transverse fire locations under the elliptic ceiling into account. Then the results calculated by the proposed formula were compared with the experimental measured maximum ceiling temperature along the main tunnel and shows good agreement. Finally, effects of vertical wall and ceiling height on temperature decay trend in branch tunnels were investigated by analyzing the accumulation and descendant of smoke in front of the portals based on measured temperature data.