Study on the influence of low pressure and low oxygen environment on fire detection
The total area of China's plateau is about 1 / 3 of the land area, of which the total area of the Qinghai Tibet Plateau is 2.5 million square kilometers, with an average altitude of more than 4000 meters, known as the "roof of the world". The average air pressure and oxygen density in the plateau environment are lower than that in the atmospheric environment, and the combustion characteristics and rules of the fire are obviously different from that in the atmospheric environment, which have different effects on the fire detection parameters such as smoke, flame, gas and temperature signals, thus affecting the detector response.
The complex coupling effects of low pressure and low oxygen on the pyrolysis, vaporization and combustion of liquid fuel under different heat feedback mechanisms were studied by comparing different sizes of pool fires in Lhasa and Hefei.
Due to the change of heat feedback mechanism, the effect of air pressure on pool fire combustion rate varies with the increase of fire source size. When the fire source is small, the combustion rate in plateau area is faster, because the laminar combustion and heat feedback are mainly controlled by conduction and the flame temperature increases. With the increase of fire source size, the ratio of combustion rate in plateau area to that in normal pressure area tends to increase The reason is that the heat feedback is turned to radiation control and the radiation is lower in plateau area.
The total area of China's plateau is about 1 / 3 of the land area, of which the total area of the Qinghai Tibet Plateau is 2.5 million square kilometers, with an average altitude of more than 4000 meters, known as the "roof of the world". The average air pressure and oxygen density in the plateau environment are lower than that in the atmospheric environment, and the combustion characteristics and rules of the fire are obviously different from that in the atmospheric environment, which have different effects on the fire detection parameters such as smoke, flame, gas and temperature signals, thus affecting the detector response.
The complex coupling effects of low pressure and low oxygen on the pyrolysis, vaporization and combustion of liquid fuel under different heat feedback mechanisms were studied by comparing different sizes of pool fires in Lhasa and Hefei.
Due to the change of heat feedback mechanism, the effect of air pressure on pool fire combustion rate varies with the increase of fire source size. When the fire source is small, the combustion rate in plateau area is faster, because the laminar combustion and heat feedback are mainly controlled by conduction and the flame temperature increases. With the increase of fire source size, the ratio of combustion rate in plateau area to that in normal pressure area tends to increase The reason is that the heat feedback is turned to radiation control and the radiation is lower in plateau area.