Experimental Study On Influence Of Fire Locations On Compartment Fire Characteristics

In compartment fire studies,the occurrence of fire in a compartment with a single opening is the most basic form.For the well-ventilated compartment fire,the internal temperature distribution is usually in the form of double layer distribution.The flow status at the opening determines the process of mass exchange between the inside and outside of the compartment and affects the development of fire spread and the internal combustion state.Most of the previous studies focused on the effect of the shape of opening or atmospheric wind on the flow process.In this paper,the temperature distributions of the compartment fires and the flow characteristics were studied under various fire scenarios with different fire locations and heat release rates.The experimental results show that,for the fire scene with the same heat release rate,the closer the fire is to the opening,the longer time it takes for the temperature to reach the stable state.The temperature distribution in the compartment will change with different fire locations.When fire moves from the wall to the opening in the horizontal direction,the upper temperature of the compartment will decrease while the lower temperature increase.For a single opening compartment with in well-ventilated condition,the internal temperature distribution presents a stratified scenario.The temperature distribution inside can be described by a Boltzmann distribution function.The dimensionless average temperature rise in the upper and lower layers of the compartment can be correlated by the dimensionless heat release rate and the dimensionless fire location.The flow characteristic at the opening is significantly influenced by the fire location.The height of neutral plane and velocity distribution change significantly with the fire location.The height of the neutral plane and the height of the smoke layer will decrease with the fire moving towards the opening in horizontal direction.The height of the smoke layer in the compartment is significantly affected by the variation of fire location than by the change of the heat release rate.It is found that the height of the neutral surface will lead to a significant variation in the height of the smoke layer under a given inside temperature.The mass flow rate of the opening is affected by the location of the fire and the heat release rate.The mass flow rate increases with the increase of the heat release rate,and increases with the fire moving towards the opening.The influence of the variation of fire location near the wall and the opening is significantly greater than that change on the central location of the compartment.The flame shape is significantly affected by the fire location.As the fire moves from the sidewall to the opening,the flame shape changes from vertical combustion state to inclined state,and finally gets close to the ground,showing the phenomenon of flame base drag.The variation of flame shape can be accounted for by the limited wall entrainment and the effect of opening flow.As the fire moves from the wall to the opening,the flame height decreases significantly and the flame horizontal extent increases.Based on the experimental data,a new correlation of the flame horizontal extent coupled with the fire location is proposed.