A two-dimensional nodal model with turbulent effects for the synthesis of Si nano-particles by inductively coupled thermal plasmas

Abstract

Nano-particle synthesis by means of inductively coupled plasma torches is a material process of large technological interest. Numerous parameters are involved in the optimization of this process; hence the development of numerical models for the prediction of thermal and magneto-fluid dynamics fields, precursor powder trajectories and thermal history, as well as nano-particle formation and growth, is necessary for the up-scaling of these devices from laboratory batch production to an industrial continuous process. In this work, a two-dimensional (2D) discrete-type model (nodal model) for the analysis of nano-powder nucleation and growth is presented, taking into account convection, diffusion and turbulent effects on particle formation. Discrete-type models feature high precision and reveal a great deal of information useful for clarifying the nano-particle formation process. Using Si as the precursor material, 2D simulations of a nano-particle synthesis RF plasma apparatus with a reaction chamber are carried out. Good agreement is found when comparing results obtained with this model with those coming from a well-established nucleation-coupled moment method. Moreover, the extended amount of obtainable information that characterizes the nodal model is underlined.

Numerical Study of Axial Magnetic Effects on a Turbulent Thermal Plasma Jet for Nanopowder Production Using 3D Time-Dependent Simulation

“…As a result, the nanopowder has larger particle sizes due to more significant condensation. This tendency coincides with a result obtained by a different computational work [13]. A double-layer structure of high-temperature thicker vortex rings surrounded by low-temperature thinner vortex rings is generated in the upstream region.…”

“…By virtue of its simplicity, the computation can be performed with a lower computational cost than other models [8]- [13], [16].…”

“…(Most of their works focused on plasma generation inside the nozzle.)  Up to now, simultaneous growth and transport of nanopowder in/around thermal plasma flows have been simulated only under 2D steady conditions which are oversimplified assumptions [8]- [13]. In nature, nanopowder's growth and transport as well as turbulent plasma flows should be 3D and time-dependent.…”

Design-Oriented Modelling of Different Quenching Solutions in Induction Plasma Synthesis of Copper Nanoparticles

“…where is the vapour concentration, 0 is the monomer volume, is the vapour mass source term accounting for the production rate due to evaporation, whereas is the vapour mass source term accounting for the consumption on behalf of nucleation and condensation, and is the total vapour diffusion coefficient, accounting for turbulence as described in [6].…”

“…However, due to the large number of variables that characterize the process, optimization is a challenging task, that can hardly rely on try and fail experimental approaches, because of the equipment cost and the limited amount of information that can be obtained from conventional diagnostic techniques. For this reason the investigation of the performance of nanoparticle synthesis processes in a RF-ITP system has relied extensively on modelling techniques [5][6][7]. The precursor evaporation efficiency (the fraction of the injected precursor that is effectively evaporated in the plasma) is one of the key parameters to evaluate the performance of the process.…”