Analysis of the hottest combustion and explosion

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Combustion and Explosion Analysis

damage distribution can provide strong evidence of the fire source area Wood burns for the longest time. Carbon Jinan assaying tensile tester is mainly used for non-metallic materials such as tape, rubber, plastic, sea/foam, waterproof materials, wires and cables, textiles, mesh ropes, non-woven fabrics and metal wires, metal foils, metal plates and metal rods. The degree of experimentation is also the deepest Experience shows that it takes 40min for this material to carbonize 2.5cm If you know the fire extinguishing time from the firefighter, you can determine the fire source area from the carbonization depth measurement

many UTMS have interchangeable dynamometers. The condition of containers after disasters can provide valuable evidence of the length of combustion time When any container is exposed to the flame, the liquid loaded can prevent the damage of the paint coating in the container, and the container wall coating above the liquid level will explode If the original liquid level in the container is known, the liquid level after the fire can be checked in combination with the above characteristics of the container, so it is not difficult to determine the evaporation capacity and evaporation heat of the liquid

the melting point of pure copper is 1080 ℃. Generally, pure copper can withstand the effect of combustion Copper alloys, such as brass and bronze, have a melting point between 800 and 1000 ℃, and usually melt in a fire After a fire, copper alloy droplets will adhere to other metal surfaces If pure copper droplets are found on the conductor, it indicates that there is current passing through in the fire. If it is too low, the gas will overflow from the plastic, strengthening the heat of combustion If there is a cable passing through, the current is cut off due to the cable fusing in the early stage of combustion. At this time, the pure copper droplets and the arc flame dent on the pure copper conductor become strong evidence of the fire source area

the melting point of iron and steel is between 1300-1500 ℃, which generally will not melt in a fire. Between 550-600 ℃, amazing distortion will occur Distortion and deformation of structural steel parts can be seen everywhere in fire, which is of little significance in fire investigation

2. Explosion Analysis

(1) the performance mode of explosion effect

many factors affect the mode of container fracture

in the limit case of static overload, the detonation of condensed phase under pressure will produce brittle fracture

for the case of relatively slow gas deflagration, the mode of fracture is purely elastic, and the starting point of fracture is at the weak point of the container After the moment of deflagration fracture, the pressure continues to rise, mm; More debris will be produced at this time The slow pressurization process in the container will initially produce elastic fracture, then crack, and finally accelerate to brittle fracture

therefore, it is important to find the initial fracture point In the case of brittle fracture, the fracture mark of the container fragment will point back to the initial point For most cases of elastic fracture The initial point is usually near the thinnest part of the container

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