Applications of thermal plasma flow, energy and particle nucleation fields control in the materials and energy sectors

该研究项目是基于“热等离子体”技术的开发，该技术由电离气体组成，在极端温度达到1万摄氏度，接近大气压。热等离子体器件在本程序中用于生成碳基纳米结构，如石墨烯纳米片（GNF）。GNF是具有少量原子层的二维片状材料，这些原子层是在我们的反应堆中从原子水平通过在4400℃至5200℃之间发生的粒子成核而产生的。研究计划的特别重点是在合成反应堆内开发控制策略，这将使三个特定领域的应用在能源部门，环境和先进材料中开辟新的机会。研究了热等离子体反应器的设计，包括等离子体流场和温度场，以及在反应器内发生的粒子成核映射和产生的化学物质。特别着重于等离子体流膨胀的控制。作为第一个应用，这种控制提供了使用等离子体中产生的“活性”化学物质在粉末和表面上添加化学功能的可能性，同时保持表面相对寒冷和在大气压下。第一个应用的例子将是在快速工业规模上制造完全可湿性（亲水）或完全不可湿性（疏水）表面（例如木材或颗粒）。流量控制的第二个应用是在能源和环境领域，特别关注加拿大北部的292个社区，这些社区使用独立于配电网系统的柴油电力。这些发电机产生大量的温室气体（GHG），但由于它们的开/关能力差，无法适应能源需求，也造成了重要的电能损失。开发的等离子体系统使用温室气体（甲烷）来产生碳基颗粒，氢气作为副产品。因此，氢可以作为一种储存多余电能的手段，然后通过基于燃料电池的系统进一步用于提供电力。该项目旨在设计一种等离子体反应器，以优化氢气生产，同时保持高附加值的碳粉生产，并消除温室气体。等离子体流量控制的第三个应用涉及用于生产先进涂层的等离子喷涂应用，特别是用于航空部门。等离子体喷射的一个长期难题是如何控制在湍流等离子体流中喷射的粒子的热历史。本文采用基于等离子体膨胀的控制策略来产生更均匀的流型，提高等离子体喷涂过程的效率。

This research program is on the development of technologies based on "thermal plasmas" consisting of ionized gases at extreme temperatures reaching 10,000 C and close to atmospheric pressure. Thermal plasma devices are used and modeled in the present program for generating carbon-based nano-structures such as graphene nanoflakes (GNF). The GNF are in the shape of 2-dimensional sheet-like materials having a small number of atomic layers, these being generated in our reactors from the atomic level through particle nucleation occurring between 4,400 C and 5,200 C. A particular emphasis of the research program is in the development of control strategies within the synthesis reactors that will enable three specific areas of applications opening new opportunities in the energy sector, the environment, and advanced materials. Thermal plasma reactor design are studied in terms of the plasma flow and temperature fields, as well as particle nucleation mapping occurring within the reactor and the chemical species being generated. A particular focus is made on the control of the plasma flow expansion. This control provides, as a 1st application, the possibility to use the "active" chemical species generated in the plasma to add chemical functionalities on powders and surfaces while maintaining the surfaces relatively cold and at atmospheric pressure. Examples of this 1st application would be to make fully wettable (hydrophillic) or fully non-wettable (hydrophobic) surfaces (wood or particles for example) at rapid industrial scales. A 2nd application of the flow control is in the energy and environment sector, focusing particularly on the 292 northern Canadian communities using diesel-based electrical power independent from the electrical distribution grid system. These power generators produce a large amount of greenhouse gases (GHG) but also an important loss of electrical energy due to their poor on/off capabilities for adjusting to the energy demand. The plasma systems developed uses a GHG (methane) for generating the carbon-based particles, and hydrogen as a by-product. Hydrogen can thus act as a means of storage of the excess electrical energy generated, and then further used to provide electricity through fuel cell based systems. This program targets the design of a plasma reactor that will optimize hydrogen production while maintaining the high added value carbon powder production, and eliminating a GHG. A 3rd application of the plasma flow control relates to plasma spraying applications for producing advanced coatings particularly for the aeronautics sector. A constant problem in plasma spraying is controlling the thermal history of the particles injected in the very turbulent plasma flow. We apply here our control strategies based on plasma expansion to generate more uniform flow patterns and increase the efficiency of plasma spraying processes.