DEVELOPMENT OF A COMPUTER CONTROLLED SHOCK TUBE SYSTEM FOR THE STUDY OF HIGH TEMPERATURE CHEMICAL KINETICS

这项研究的主要目标是开发一种反应堆，以便在高温下获得可靠的化学动力学数据。采用计算机控制系统对激波管进行自动操作。该系统的主要功能包括：1)通过监测试验段的真空度来控制抽气系统，2)控制驾驶员段的高压气体供应和低压段的样品气体供应，3)通过操作电磁阀控制主活塞和辅助活塞产生冲击波，4)从数字示波器传来数据存储，确定冲击波的温度和压力，利用单个物种的校准曲线和化学动力学分析将观察到的ARAS的吸收强度转换为绝对浓度，以及5)紧急要求(水、电和气体泄漏)的操作。性能测试已经完成，所有功能都运行得很好。用于激波管研究的自动控制系统已成功地排除了由人工操作或与标准型激波管有关的激波速度波动引起的误差。这样获得的动力学数据的质量已经得到了广泛的改善：通过对相同激波速度下的几次发射的数据进行平均，可以改善S/N比和由于数据随机波动而引起的误差。此外，还利用准分子激光光解方法获得了各种原子/自由基反应的直接信息。

The main goal of this study is to develop a reactor in order to obtain reliable chemical kinetic data at elevated temperatures. A computer controll system is employed to operate a shock tube automatically. The main functions of the system include : 1) controll the evacuation system by monitoring the vacuum level in the test section, 2) controll the high pressure gas supply in the driver section and the sample gas supply in the low pressure section, 3) generation of shock waves by operating solenoid valves for controlling the main and auxially pistons, 4) data storage transfered from a digital oscilloscope, determination of the shock wave temperature and pressure, conversion of the observed absorption intensity of ARAS into the absolute concentaration by use of the calibration curves for individual species, and chemical kinetic analyzes, and 5) operation of the emergency requirements (water, electricity, and gas leakage) . Performance tests have been already finished and all the functions are working very nicely. The automatic controll system for the shock tube study has been successful in excluding the errors due to manual operation or the fluctuation of the shock speeds associated with a standard type shock tube. The quality of the kinetic data thus obtained has been extensively improved : S/N ratio and errors due to random data fluctuations some time observed in shock tube runs can be improved by averaging the data for only several shots at the same shock speed. Moreover, an excimer laser photolysis method is used to obtain : the direct information of various atom/radical reactions.