Abstract:

In order to prevent and control the fire hazard of a road tanker coupling with diesel leaking and burning, small-scale experiments were first conducted using a 5 L tank filled with 1.65 L of 0# diesel fuel. The diesel was released from the tank bottom and burned, and the temporal evolution of the fuel temperature, tank pressure, thermal radiation, and flame morphology was investigated. Subsequently, numerical simulations of tank thermal exposure were conducted. The results show that once the temperature of leaking diesel reaches 227.8 ℃, the diesel fuel leaking to the external environment will boil and burn. This leads to a sudden escalation of fire hazard, i.e., a sudden increase in the tank pressure, the thermal radiation and flame size. The onset time of hazard escalation increases exponentially with filling level. When the filling level rises from 33% to 80%, the onset time increases by an average factor of 2.32 across different thermal boundary conditions. Flame offset relative to the tank reduces the thermal load on the tank, thereby lowering the diesel temperature-rise rate and increasing the onset time. Moreover, the rising rate of the onset time grows with the flame offset degree. The increase in the onset time provides more available safe egress time (ASET). Thus, ASET increases as both the filling level and the flame offset degree increase.

Key words: diesel road tanker, leakage fires, numerical simulation, sudden fire hazard escalation, diesel temperature