Multi-sensing Control of Plasma Flow Systems Utilizing Super Functionalization

利用外加磁效应，通过注入汽化金属和活性气体，再通过注入细颗粒，建立了多功能等离子体流动的多传感控制系统，并进行了实验和理论研究。主要研究结果如下：(1)通过控制辐射强度和操作磁通密度，成功建立了等离子体射流稳定的多传感控制系统。实验明确了辐射强度对流量突变的定值控制性能，并进一步阐明了等离子体射流动力学行为对进口流量振荡的控制性能。(2)通过数值模拟阐明了钾的施用频率和播种比例对电感耦合等离子体热流体场和注入的各种金属粉末相变的影响。(3)考虑加载效应、相变、热物性变化、可压缩效应和复杂构型，对载气、颗粒和水滴三维多相等离子体射流进行了密集加载数值分析。(4)通过建立强逼真模型，对等离子喷涂过程、电弧熔灰过程和电弧电极系统进行了计算模拟。获得了最佳的操作条件和等离子枪的几何形状，以提高工艺效率和延长寿命。(5)采用超功能化方法开发了DC-RF混合等离子体系统。通过控制鞘气与载气的流量比，实现了等离子体火焰的伸长率和均匀的温度分布。在此基础上，利用PIV系统对螺旋区的涡流结构进行了可视化分析。

The experimental and theoretical studies were carried out to establish a multi-sensing control systems for functional plasma flow by utilizing the applied magnetic effect and by seeding vaporized metal and reactive gas and further by injecting fine particles. The main results obtained here are as follows:(1) A multi-sensing control system for plasma jet stabilization was successfully established by controling the radiation intensity and by operating magnetic flux density. The constant value control performance of radiation intensity for sudden flow rate variation and further the control performance of plasma jet dynamic behavior for oscillating inlet flow rate were clarified experimentally.(2) The effects of applied frequency and seeding ratio of potassium on thermofluid field of inductivley coupled plasma and phase change of various kinds of metal powders injected were clarified by numerical simulation.(3) 3D multiphase plasma jet with carrier gas, particles and water droplet in dense loading were numerically analyzed by taking loading effect, phase change, variation of thermophysical properties, compressible effect and complex configuration into account.(4) Computational simulation for plasma spraying process, arc ash melting process and arc-electrodes system were conducted by developing strongly realistic model. The optimal operating conditions and plasma gun geometry were obtained to increase process efficiency and to extend life time.(5) DC-RF hybrid plasma systems were developed by super functionalization. The elongation of plasma flame and uniform temperature distribution were achieved by controlling the flow rate ratio of sheath gas to carrier gas. Furthermore, vortex flow structure in the coil zone was visualized by using PIV system.