Abstract: Abstract: In order to explore the maximum temperature rise law of ceiling smoke in point exhaust tunnel fire, the 1∶10 experiment was conducted to study the development process of fire plume and the temperature distribution of ceiling smoke in tunnel longitudinal center line under different fire source power, fire location and smoke exhaust rate. According to the dimensional analysis method, the mathematical model of the maximum temperature rise under the ceiling is derived. The results show that the maximum temperature in the longitudinal center line of the tunnel does not change with the smoke exhaust rate, but the maximum temperature in the ceiling decreases with the increase of the smoke exhaust rate, and increases with the increase of the fire source power and the distance between the fire source and the exhaust vent. The dimensionless maximum temperature rise is proportional to the 0.034 power of the dimensionless fire location and increases with the increase of the fire source power.

Key words: point exhaust system, dimension analysis, fire location, smoke exhaust rate, maximum temperature rise of smoke