声悬浮反应器的设计与控制

THE DESIGN AND CONTROL OF AN ACOUSTIC LEVITATILN REACTOR

介绍了作者为研究气固或气液体系单颗粒的物理和化学变化过程而研制的声悬浮反应器的设计和控制。该反应器除作为主体的单轴谐振式声悬浮装置外，还包括通过自动调节腔长，维持腔室谐振的谐振跟踪系统，与谐振跟踪系统同时作用，通过相对于窗口平移谐振腔室而使颗粒稳定悬浮在对准窗口位置的颗粒位置控制系统，ＣＯ＿２激光加热系统，红外辐射测温系统，以及为实时控制颗粒温度和位置及采集颗粒图象的微机系统。文中详细叙述了谐振跟踪和颗粒位置控制系统，以及ＣＯ＿２激光能量的脉冲调制方法和反应过程中材料谱发射率明显变化的颗粒的单色红外测温方法。常温和加热颗粒悬浮实验结果表明，这些控制系统的性能是良好的，同时对于用声悬浮反应器进行单颗粒反应研究，这些系统的功能是不可缺少的。

The design and control of an acoustic levitation reactor developed for studying physicaland chemical processes of single particles,particularly in gas-solid or gas-liquid reactions,ispresented.The completed device consists of a single-sound-source acoustic levitation apparatusmodified to accommodate a resonance tracking system that automatically adjusts the chamberlength required to maintain the chamber at resonance,a particle position control system thatoperates simultaneously with the resonance tracking system to center the freely suspended par-ticle about the access ports by translating the resonant chamber relative to the windows,axes,aheating system based on a cw CO_2 laser,a temperature measurement system applying in-frared pyrometry,as well as a microcomputer system to accomplish real-time control of particletemperature and position and to acquire the particle image. In this paper,the resonance track-ing and particle position control systems,as well as the techniques for pulse modulation of CO_2laser energy,and temperature measurement by single wavelength infrared thermometry forparticles whose emissivity varies obviously during the course of reaction are described in detailand examined experimentally.It is demonstrated that these systems operate satisfactorilv atambient and elevated temperatures,and their functions are essential for the investigation ofheterogeneous reaction kinetics of single particles in an acoustic levitation reactor.