Mathematical modelling of the nanopowders production in Inductively Coupled Plasma reactors

纳米粉末的生产是一种纳米技术，已经对工业产生了重要影响。纳米粉末的性质不同于块状材料，因为它们的大小接近分子尺寸。这些材料通常具有全新的性能。纳米金属粉末、纳米陶瓷或纳米复合材料具有机械、化学、光学、磁性和电子性能，与具有相同化学成分的微米粉末相比，这些性能得到了增强。例如，作为铁磁记录材料使用了几十年的微米级氧化铁在室温下获得了纳米级的超顺磁性。高能材料是纳米粉体性质变化的例子，与微米当量相比，纳米铝粉具有自燃强烈的尺寸依赖性。在可用于工业规模生产纳米粉末的技术中，电感耦合等离子体（ICP）具有许多优点：高温蒸发任何类型的前体，相对较大的尺寸和在受控化学环境下的低速度。由于这种反应器中的流量场、温度场和浓度场非常复杂，并且在这种反应器中生产的纳米粉末在很大程度上依赖于这些场，因此在ICP纳米粉末生产反应器的设计中，完整的表征是至关重要的。该项目的目标是建立ICP反应器中纳米粉末生产的数学模型，使科学家和工程师能够设计和优化反应器。该项目将首先涉及物理化学现象的基础数学建模研究：1)均质成核理论2)纳米粒子表面反应速率3)纳米粒子聚集。它将进一步涉及应用数学、数值和工程研究，将涉及：1)热等离子体中纳米颗粒产生的数学建模的最新进展2)人口平衡方程求解方法（矩量法和节点法）的实现和验证3)工业热等离子体反应器中淬火方法的全面三维建模研究4)开源平台OpenFOAM中数值模型的优化。

The production of nanopowders, whose properties differ from the bulk material due to their size close to molecular dimensions, is a nanotechnology that has already had an important industrial impact. Often these materials have completely new properties. Nanometallic powders, nanoceramics or nanocomposites have mechanical, chemical, optical, magnetic and electronic properties that are enhanced compared to micrometric powders with the same chemical composition. For example, micron- sized iron oxide which is has been used as a ferromagnetic recording material for decades acquires at nanometric sizes super-paramagnetic capabilities at room temperature. Energetic materials are examples of nanopowders properties change compared to the micrometric equivalent, nano-aluminum powders have a spontaneous ignition strongly size-dependent. Among the technologies available to produce nanopowders at industrial scale, the Inductively Coupled Plasma (ICP) presents numerous advantages: high temperatures to vaporize precursors of any type, relatively large size and low velocities with a controlled chemical environment. As the flow, temperature and concentration fields in such reactors can be very complex, and since the nanopowders produced in such reactors depend heavily on these fields, a complete characterization is of outmost importance in the design of ICP nanopowders production reactors. It is the objective of this program to develop a mathematical model of the nanopowders production in an ICP reactor that will enable scientists and engineers to design and optimize the reactors. The project will involve first a fundamental mathematical modelling study of the physico-chemical phenomena dealing with: 1) homogeneous nucleation theory 2) nanoparticle surface reaction rates 3) nanoparticle aggregation. It will further involve an applied mathematical, numerical and engineering study that will deal with: 1) the state of the art of the mathematical modelling of nanoparticle production in thermal plasmas 2) the implementation and validation of the Population Balance Equations solution methods (Method Of Moments and Nodal methods) 3) a comprehensive 3-D modelling study of the quenching methods used in industrial thermal plasma reactors 4) the optimization of the numerical model in the open-source platform OpenFOAM.