通风条件对热塑性材料燃烧行为影响的试验研究

Experimental study on combustion behavior of thermoplastics with different ventilation conditions

热塑性材料燃烧过程中,固体壁面火和液体油池火同时存在且相互影响。为了研究通风条件对受限空间内热塑性材料熔融流动燃烧行为的影响,选择5 mm厚的聚丙烯板材作为研究对象,设置了 6种不同的通风条件,在ISO 9705标准燃烧室内,进行了.系列的大尺寸燃烧试验。试验过程中测量了热释放速率、CO体积分数以及温度场等火灾动力学参数。考虑到通风口宽度变化与高度变化的区别,引入了通风口位置高度的无量纲因子φ。结果表明,通风条件对热塑性材料的火灾规模有一定影响,并且通风口高度变化的影响比宽度变化的影响更显著。燃烧过程中,热释放速率峰值与修正后的通风因子呈线性关系。

The aim of this paper is to investigate the effect of ventilation conditions on the combustion behavior of thermoplastics in enclosure. As is known, thermoplastics is of extremely unique advantages, such as easy in manufacturing, light in weight, cheap in production cost, waterproof as well as corrosion-resistant, all of which help to make it widely used in industry as well as in daily life. However, as most thermoplastics are flammable, great concern should be paid to the potential fire risk of its application in architectural buildings. As is reported, there exist wall fire and pool fire hazards plus the accel- erated fire-spreading speed in the process of the thermoplastic fire. The combustion process is actually affected by many factors, such as ignition method, thickness of sample and ventilation condition. In our research, we have conducted a series of largescale experiments on polypropylene sheets with thicknesses of 5 mm in ISO 9705 fire testing rooms with different ventilation conditions controlled. In addition, we have measured systematically fire dynamics parameters, such as the heat-releasing rate, CO concentration and temperature field, were. Repetitive experiments were completed in order to get useful data. Considering the differences between width and height of ventilation, we have put forward a non-dimensional parameter of height location. The experimental results we have gained show that ventilation condition plays a key role on peak HRR value, though the height variety may have greater effect than the width variety. The peak HRR value proves to be in linear form with the ventilation conditions, including the size and height of the ventilation.