Abstract: The mathematical relationship between the fuel oil pool area and heat release rate is investigated by systematically analyzing tunnel fire types, oil pool sizes, and heat release rates in 33 cases globally. The heat release rates of various fuel sources (alcohols, alkane, and fossil) with varying oil pool areas are compared. Smallscale fire tests are performed to verify the fitting mathematical relation of #90 gasoline. The results show the following. (1) In the Chinese tunnel fire model test, fossil fuels and alcohols accounted for 56% and 31%, respectively, whereas alkanes and fossil fuels accounted for 29% in fire sources in other countries. (2) The larger the pool area, the greater the fuel combustion, mass loss, and heat release rates. Linear calculation and error formula of the heat release rate and oil pool area of various fuels are obtained and experimentally verified. (3) Under the same oil pool area, the fuel heat release rate order from most to least is #0 diesel, n-heptane, #90 gasoline, 99% alcohol, and methanol. The differences between the five fuels are evident with an increasing oil pool area.

Key words: tunnel fire, heat release rate, oil pool area, model test, fire source fuel