The Research On The Combustible Behavior Of Spilled Flame Under A Projection Of The Building Fa?ade Base On The Image Processing Technique

Because the society developed, the mount of high-rise building and people is getting more. The character of high-rise building is that it can lose lots of lives and fortune when it was on fire. The flame come out to burn through the opening of building, it is a way to spread the fire hazard. The fireproofing cornice is a way to control the fire spread. The fireproofing cornice is a fire-resisting wall installing horizontally on the top of opening. Because the researches on the fireproofing cornice that can resist the spilled flame are less, building codes don’t require the size of fireproofing cornice clearly. This experiment researches on the flame behavior under the huge fireproofing wall, the aim is to provide a basis for the size of the projection.First, this paper set up a little-scaled compartment in a length ratio of 1:6. The thermocouples were used to measure the temperature inside the compartment. To compare the temperature inside the compartment with or without the projection, we conclude that the projection can affect the air inflow through the opening less.Second, the image processing technique was used to obtain the instantaneous flame area and image correlation during a period of time. The flame images are processed by the time averaged treatment, we measure the length of flame under the projection to find out that the flame length correlates with the opening aspect ratio and heat release ratio. We assume the flame shape as a rectangle and a half circle, like a mushroom by the result of the image processing technique. We measure the vertical temperature distribution under the projection to assure the thickness of flame does not change in the hot temperature region. Then we calculate the neutral height of opening to determine the flame thickness in different case by three methods.Eventually, we separate the flame region into two parts, one is rectangle, the other one is a half circle. We conduct the velocity expression of each part separately as expression(6.32),(6.45). The rectangular entrainment number is calculated as 0.03 recE =. The total air entrainment mass flowCr Rm=&can be correlated with half circular entrainment numberhcE through expression(6.49). The expression(6.49) can be exchanged by expression by(6.48) to express the correlation of excess air number n and the total air entrainment mass flowCr Rm=&. The total air entrainment mass flow Cr Rm=&can be expressed with excess air number n in another way by expression(6.9). The average excess air number can be calculated as n =1.3 in experimental case, the half circular entrainment number is 0.03 hcE =. The excess air number n can also be calculated by smoke components as n =1.5. At last, the flame length under projection can be predicted as expression(6.58).