多孔活性自燃金属的光谱辐射特性研究

摘要

多孔活性金属材料因为内部存在大量的孔隙,大大地增加了与空气的接触面积,使得其在空气中的燃烧较为猛烈,燃烧温度迅速上升.其燃烧过程属于固体燃烧的范畴,较为复杂.以镁为例,通过建立燃烧模型,来研究多孔活性金属的光谱辐射特性.首先,建立氧气总消耗量与活性金属剩余质量的关系,研究氧气在活性金属孔隙内的扩散浓度关系,通过求解活性金属热平衡方程得到活性金属燃烧过程中温度与时间的关系式,进而得到活性金属的峰值光谱辐射强度表达式;然后,将模型计算的仿真结果与红外热像仪测得的实验结果对比,结果表明,模型的计算结果与实验结果相一致,误差在了10%以内;最后,通过建立的燃烧模型来研究活性金属燃烧规律以及其光谱辐射特性,解决了高空、高速下的活性金属光谱辐射强度难以实验获得的问题,大大减小了实验成本与时间.分别对比不同时间活性金属箔片在1~3,3~5以及8~12μm波段下的辐射强度,得出活性金属燃烧时的辐射强度主要集中在3~5μm波段的结论.研究结果表明:自燃金属最大燃烧温度随高度的增加逐渐下降,随气流速度的增加先增加后减小,在速度为30 m·s-1时,温度达到最大;自燃金属的光谱辐射强度在2~6μm波段达到最大.该模型也可以用来研究其他活性金属的燃烧特性.%The contact area between multi-hole activated metal and air greatly increases ,because of the large number of holes in multi-hole activated metal .So the combustion of multi-hole activated metal is serious in the air ,w hich causes the temperature rising rapidly .The combustion process is quite complex and belongs to solid combustion .To solve the combustion problem of multi-hole activated metal ,magnesium was chosen as the activated metal in the paper .The combustion models were established to research the spectral radiation characteristics .Firstly ,we established the relationship between total consumption of oxygen and residual mass of activated metal and studied the diffusion concentration of oxygen in activated metal hole .The relationship between temperature and time were obtained by solving the heat balance equations of active metal in the process of combustion . Secondly ,the simulation results by calculation were compared with the experiment results which were obtained by thermal imager .The results demonstrated that the model calculated results consistent with experiment and the error was controlled within 10% .Finally ,the burning rule and spectral radiation characteristics of activated metal were studied by the establishment of combustion models .So the problem that the spectral radiation intensity is difficult to be obtained by experiment at high altitude and velocity was solved ,which decreased the experiment cost and time .The activated metal radiation intensity in the waveband of 1~3 ,3~5 and 8~12 μm were compared at different time and get the condusion that the nain radiation intensity focuses on the waveband of 3~5 μm .The results demonstrated that :the maximal burning temperature increased firstly and then decreased with the increase of the velocity .It also decreased with the increase of the altitude;The temperature reached maximum at the speed of 30 m · s-1 ;Activated metal spectral radiation intensity reached maximum at the waveband between 2 to 6 μm .The models can be applied in studying other activated metal burning characteristics .