On the use of high-temperature, high-pressure shock waves in gases for the controll of fine particle synthesis and chemical reaction

该项目旨在证明在气体中使用很强的冲击波来合成非常细的粉末和控制化学反应的可行性。我们主要致力于通过测量与冲击传播有关的现象来获得实现该方法所需的基本信息。通过构造凝汽器库，利用线爆炸产生了很强的冲击波。在不同的导线材料、长度和环境气体下进行了实验。对爆炸产生的冲击传播的电气测量表明，距离电线几十毫米处的冲击速度和压力分别约为2公里/秒和50巴。在脉冲激光阴影图中可以看到激波锋后区域的粒子状云。每次射击后观察到的大量烟尘可能是由于云的成核过程。利用大维代数玻璃的法拉第效应，实现了同一过程的时间分辨光谱。为此，又建了一座小型快速堤。利用图像增强器对几种金属丝进行了光谱成像，为颗粒合成阶段提供了有用的信息。最后，对高多孔粉末的冲击入射进行了测试，获得了波在粉末中的传播数据。

This project aims at the demonstration of the feasibility of very strong shock waves in gases for the synthesis of very fine powders and controll of chemical reaction. We have devoted mainly to obtain fundamental information necessary to realize the method by measuring the phenomea associated with shock propagation.Very strong shock waves were generated by using the wire explosion by constructing a condenser bank. Experiments have been performed with different wire material, length and ambient gas. Electrical measurement of the explosion-generated shock propagation usggests that shock speed and pressure at several tens of mm from the wire were about 2 km/s and 50 bar, respectively. The particle-like clouds in the region after the shock front was seen in the pulsed laser shadowgraph. Large amount of soot observed after each shot might be due to the nucleation process with the clouds.Time resolved spectroscopy of the same process were realized by using the Faraday effect of the glass having large Verdet number. For this purpose, another small fast bank was constructed. Spectroscopic photos for several metal wires were taken with image intensifier to give useful information on the stage of particle synthesis.Finally, shock incidence on the highly porous powders was also tested to obtain data on wave propagation in powder.