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

本项目旨在论证气体中极强冲击波用于合成超细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波传播相关的现象来获得实现该方法所需的基本信息。通过构建冷凝器组，利用导线爆炸产生了非常强烈的冲击波。用不同的线材、长度和环境气体进行了实验。爆炸冲击波传播的电测结果表明，在距导线几十毫米处的冲击波速度和压力分别约为2公里/S和50bar。在脉冲激光阴影图上可以看到激波阵面后区域的颗粒状云团。利用费尔德数较大的玻璃的法拉第效应，实现了同一过程的时间分辨光谱。为此，建造了另一个小型快速存储体。用像增强器拍摄了几种金属丝的光谱照片，为颗粒合成阶段提供了有用的信息。最后，还测试了冲击波对高孔隙率粉末的入射，以获得粉末中波的传播数据。

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.