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试验主要观察处于阴燃状态的少量聚氨酯泡沫样品的流速、氧气浓度和辐射热通量对气/固界面的影响。因为此试验研究对象是少量聚氨酯汽沫,所以阴燃蔓延以及转化到有焰燃烧时必须借助于降低热损失并同时增加其氧气浓度。试验中,我们把呈平行六面体的样品竖向放置在风道中。样品的其中三个侧边处在高温状态,第四边暴露在上升气流和辐射中。结果发现,随着气流流速的降低以及氧气浓度的增加,或者增加辐射通量,都会加快其变成有焰燃烧的过程,减少这种变化的延误时间。试验结果表明,炭化部位内部的有焰变化因阴燃作用而出现滞后,这已经通过超声波穿透样品内部得到了证实。笔者这里给出了简化了的分析,证明这种变化可以作为一个气相燃烧程序进行处理。
The experiment mainly observed the effect of flow rate, oxygen concentration and radiant heat flux on the gas / solid interface of a small amount of polyurethane foam samples in a smoldering state. Because this test study was conducted on a small amount of polyurethane foam, the smoldering spread and conversion to flaming combustion must be done by reducing the heat loss while increasing its oxygen concentration. In the experiment, we placed the sample in the shape of a parallelepiped vertically in the duct. Three of the sides of the sample were in a hot state and the fourth was exposed to ascending airflow and radiation. As a result, it was found that as the air flow rate decreases and the oxygen concentration increases, or the radiant flux increases, it accelerates the process of turning into a flaming combustion, reducing the delay of such change. The experimental results show that the flame change inside the carbonized part lags behind due to the smoldering effect, which has been confirmed by the ultrasonic wave penetrating the inside of the sample. The author here gives a simplified analysis that proves that this change can be handled as a gas-phase combustion program.