Abstract：The phenomenon of flame intensification during fire extinguishing in the initial stage of exerting water mist influences the safety applicability of the fire-extinguishing technology of water mist. Based on the theories of physical chemistry and fire science, non-ionic liquid additives for weakening the phenomenon of flame intensification were chosen, and then a series of experiments extinguishing oil pool fire were carried out by the water mist containing non-ionic liquid additives with different mass fractions. The results showed that the water mist containing non-ionic liquid additive had better atomization characteristic parameters during fire extinguishing. The extinguishing time and the increase amplitude of maximum temperature were shortened with the increase of mass fraction of non-ionic liquid. The maximum volume fraction of CO and the time for maintaining high CO volume fraction in the fire smoke decreased with the increase of non-ionic liquid mass fraction, while the minimum volume fraction of the O₂and the recovery rate from the minimum value to the constant value increased with the increase of the non-ionic liquid mass fraction. The non-ionic liquid water mist had the function of weakening the flame intensification, and its ability to extinguish the oil pool fire was better than the pure water fine water mist. The mechanism was obtained from the non-ionic liquid water mist weakening the flame strengthening. The main fire extinguishing function was as follows: firstly, the suspended air bubbles and water bubbles formed after the non-ionic liquid water mist sprays had the functions of blocking heat radiation, blocking the supply of oxygen and isolating combustibles from oxygen. Secondly, non-ionic liquid water mist had a low HLB value of breaking ether groups under high temperature, which enhanced the ability to capture kerosene molecules and destroy H· and OH· radicals in the chain reaction. The results had a great significance for water mist fire extinguishing technology in the efficient and safe combat of oil fires.

Keyword：flame intensification phenomenon;non-ionic liquid water mist;extinguishing efficiency;suspension bubbles;