Experimental Study on Effect of Longitudinal Ventilation Velocity on Burning Rate in Tunnel Fires

摘要

In this study, the 1/20 reduced-scale experiment using Froude scaling were conducted to investigate the effect of longitudinal ventilation velocity on the burning rate in tunnel fires. The methanol pool fires with heat release rate ranging from 3.57kW to 10.59kW and the n-heptane pool fires with heat release rate ranging from 3.71kW to 15.6kW were used. The burning rate of fuel was obtained by measuring mass loss rate of the burning fuel on a load cell. The temperature distributions were observed by K-type thermocouples in order to investigate smoke movement. In methanol pool fire case, the increase in ventilation velocity reduces the burning rate. On the contrary in n-heptane pool fire case, the increase in ventilation velocity induces large burning rate. The reason for the above phenomena lies on the conflicting effect of ventilation velocity on the burning rate. In methanol pool fire case, the cooling effect outweighs the supply effect of oxygen to fire plume, and in n-heptane pool case vice versa.