The potential for deflagration to detonation transition (DDT)- Lessons from LPG tanker transportation accident

On June 13, 2020, an LPG tanker leaked, followed by a vapor cloud explosion on the highway section near Liangshan Village, Wenling City, China. The accident killed 20 people and injured more than 170, causing severe damage to the surrounding area and significant impact to the society. This work studied the large vapor cloud explosion of the LPG transportation accident in terms of the dynamic phenomena of explosion, building damage level, and mechanism of DDT. The accident analysis indicates that blast shock wave front and reaction front were moving together at a speed higher than the speed of sound; the explosion overpressure of the accident is consistent with the calculation using the detonation approach of TNO multi-energy method; the blockage level and flame acceleration distance caused by the shrubs, and the quantity of release LPG provide enough conditions for DDT occurrence. Therefore, it is believed that DDT has occurred in this accident. The findings of this work also contribute to providing scientific recommendations on preventing DDT accidents, including redesign the vegetation at incident-prone section of the highway to eliminate the condition of DDT occurrence, and optimize the transportation route to avoid highly populated areas.