振荡辐射下PMMA 热解与着火过程研究

采用正弦波变化振荡的辐射热流,对热厚PMMA(聚甲基丙烯酸甲酯)的热解和着火过程进行研究,同时采用数值模拟,对实验结果进行验证和补充。结果表明,表面温度和深度温度随着时间而增加,温度由于周期性的辐射而发生振荡,而振荡幅度随着深度的增加而衰减;表面温度与深度温度振荡存在时间延迟;着火时间随着热流振荡周期的增大而减小,主要由于平均热流密度随着周期增大而增大。

Pyrolysis and ignition of PMMA under periodic on-off radiation

In this paper, combined numerical and experimental methods are used to investigate the effect of periodic on-off heating upon pyrolysis and ignition of thermally thick poly (methylmethacrylate) material. Results show that surface and in-depth temperatures oscillate regularly as time evolves. The amplitude of the oscillation attenuates with the increasing distance of in-depth, and there is a time delay in the oscillation between surface temperatures and the in-depth temperatures. It is found that the attenuation and time delay are related to the cycle time and in-depth distance. The ignition time decreases with the increase of the cycle time, which is mainly caused by the increased average heat flux.