Project Details
Projekt
Hetero-aggregation of fine particles in supersonic flow for the tailor-made surface coating
Applicant
Professor Dr.-Ing. Sergiy Antonyuk
Subject Area
Mechanical Process Engineering
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 462536406
In this research project as a part of the Priority Program SPP, a novel hetero-aggregation process of submicron particles by mixing and desublimation in supersonic flow is developed and studied. For that the experimental setup is developed, where the nitrogen flow with sublimated material is accelerated to supersonic velocities in the Laval nozzle and then became supersaturated in the expansion chamber due to the rapid decrease in temperature and pressure. The hetero-aggregation process is experimentally investigated. Additionally, the flow field as well as particle trajectories including the particle growth due to the heterogeneous desublimation are computationally investigated with Computational Fluid Dynamics (CFD). This process will be extended to create tailor-made surface coatings by deposition of produced hetero-aggregates. The influence of the hetero-aggregation process on the coating microstructure and properties will be described. The goal of the planned experimental and theoretical research of this project is the description of relationships between the microscopic contacts and the macroscopic hetero-aggregate formation during desublimation and mixing in a supersonic flow, as well as their influence on the properties of the produced surface coating which are crucial for the surface functionalization in different technical applications. The second focus of this project is to describe the bonding mechanisms of hetero-aggregates to the surface and determine the relationships between the properties of hetero-aggregates achieved by different mechanisms and the microstructure and properties of the formed coatings with regard to possible technical application of the developed process for the surface functionalization. The generated hetero-aggregates will be characterized according to their size distribution by Scanning Mobility Particle Spectrometer (SMPS). The 3D Light Scattering Sensor will be used for the inline measurement of the particle shape. The complex flow field and particle dynamics (including homogeneous desublimation, heterogeneous desublimation and formation of hetero-aggregates by agglomeration during collisions of either core particles or hetero-aggregates with homogeneously desublimated particles) will be numerically investigated by means of CFD coupled with the Discrete Element Method (DEM). For that, a new multiscale model for hetero-aggregation of particles in a supersonic flow desublimation will be developed, which includes the processes of homogenous and heterogenous desublimation of particles on microscale and the particle dynamics and mixing on the macroscale.
DFG Programme
Priority Programmes
