Experimental Study Of Air To The Building Fire On Heat Release Rate Characteristics

In recent years, China’s urban construction has been rapid development. But city building fire accidents often occur like, often causing serious casualties and property losses.Existing studies show that smoke is a major cause of death in the building fire, smoke control of primary means is the building ventilation. However, there are conflicting technical problems in today’s building fire Ventilation :1. building fire ventilation( building smoke control) must blast: Building smoke mainly in the form of pressurized of air supplying gives outdoor fresh air.Smoke from the wind capacity building balanced perspective, also requires the introduction of outdoor air, in order to achieve conservation of mass.2. The introduction of outdoor air supply fresh air also affects fire intensity( usually measured in heat release rate) affected. Outdoor fresh cold air either by reducing the temperature of the fire source to reduce fire heat release rate, and possibly through the introduction of excess oxygen to accelerate combustion.It is necessary to clarify, in the construction field fire, air in the end( the heat release rate is expressed) have little impact on the intensity of the fire ? In engineering design how to consider these effects ? Based on this, in the full-size room for different air conditions, pilot testing of heat release rate from multiple perspectives study analyzed air fire heat release rate affect the characteristics of the following major elements:First, for the experimental testing in air supply of square fire source area heat release rate(range 0 to 20KW), respectively for different wind speeds, square fire source area, the outlet from fire source distance, the angle toward the outlet and outlet diameter from the five aspects of the impact Testing heat release rate(HRR) and analysising of data. Under the influence of air on heat release rate(HRR) characteristics that air supply of the peak heat release rate and the time to peak heat release rate affect is discussed. Studies have shown that the heat release rate(HRR) characteristics of the greater factors are changing in wind speed and oil pan area, changing in wind speed for peak heat release rate and time to peak heat release rate is linear; the larger the square area oil pan, the heat release the larger the peak rate, the time to peak heat release rate(HRR) decreases, but the change width are both progressively reduced.Secondly, researching the effects of under air supply different wind speeds and different aspect ratio of the strip fire source area for the heat release rate(HRR) characteristics. Heat release rate peak with the wind speed index relationship, time to peak heat release rate and wind speed linear relationship; Heat release rate(HRR) increased with increasing volatility area becomes large, the peak heat release rate and the time to peak heat release rate by reducing the influence of the area becomes large.Finally, under the air supply heat release rate(HRR) characteristics with square fire source area and strip fire source area were compared with analyzing and discussing. Analyzing and comparing discussions of heat release rates(HRR) under two different types of fire source area, the peak heat release rate and the time to heat release rate peak are affected by the size of area and wind speed change.