Influences of shock wave in cold shock wave extinguishing system on fire extinguishing effect and surrounding environment

A schlieren apparatus was established to experimentally evaluate the influences of the shock wave formed by the explosion of the cold shock wave extinguishing bomb on the extinguishing effect and the surrounding environment. The shock waves formed by the explosion and dispersion of the different extinguishing media and the corresponding propagations were observed based on the abovementioned schlieren apparatus. And the particle velocity behind the shock wave front at the edge of the oil pool after the explosion of the cold shock wave extinguishing bomb was calculated. Observation shows that the waterbased fireextinguishing medium can not form shock wave; and the powderbased fireextinguishing medium can form shock wave, but its strength is weak and the particle velocity is low at the edge of the oil pool. Compared with the movement of the combustible gas induced by the medium dispersion, the movement of the combustible gas induced by the shock wave may be neglected. Finally, the above conclusion was verified by a highspeed photographic experiment. So for the cold shock wave fireextinguishing system, the influences of the shock wave on the extinguishing effect and the surrounding environment are neglectable.