Simulation of Magnetically Confined Inductively Coupled Plasma

In this work, a new parallel coil design was presented to address the need for high density inductively coupled plasmas with enhanced properties and a more uniform and consistent distribution, suitable for large-area material processing. Fluid model simulations of 3D argon inductively coupled plasma (ICP) were performed in COMSOL for the proposed coil and a conventional single cylindrical coil with the same impedance to be used as reference, to compare and evaluate the performance of this new halftoroidal parallel coil design and study its effects on the main variables of the generated plasma. Through different comparisons of the simulations results, it was shown that using the new half-toroidal coil has the advantage of a higher and more uniform power deposition over the conventional cylindrical coil, resulting in a plasma with enhanced main variables and a more even distribution than those generated by the traditional methods. These improvements in the generated plasma provide a larger effective area to be used for material processing, increasing the efficiency of the system

Numerical Simulations of Airborne Particle Removal Rates for Air-Ventilated Spaces of Different Obstacle Setups

As a result of industrialization, human activities and consequently the time spent in indoor spaces has significantly increased. As airborne particles, especially those of relatively small sizes (less than 2 μm), can easily enter human respiratory tract and cross the thin air-blood barrier inside the lungs, necessary measures need to be taken to minimize exposure to these particles. In this study numerical simulations were done by coupling the “Laminar” and “Turbulent Flow” and the “Particle Tracing for Fluid Flow” interfaces in COMSOL Multiphysics to investigate the effects of obstacle setup on air flow profile and particle removal rate in a confined space of an air-ventilated office using 3D models. Particle tracing for fluid flow was used with a Newtonian formulation to simulate and trace particles with diameter of 0.5 μm and density of 1086 kg/m3. A total of 100,000 particles were simulated to reduce the uncertainty in particle concentration calculations and also to yield statistically more accurate results. Simulations were done for a control model with no obstacles, and 3 other models of different obstacle setups in a cubic room of 2.5 m * 4 m * 1 m with the same inlet and outlet configurations and a maximum interval of 180 minutes (3 hours). All cases had a monodisperse particle distribution, where particles were released transiently and evenly distributed through the entire space at the initial time step (t = 0 min). All models reached a steady-state stage after 180 minutes, with the remaining particles circulating and trapped. Analyzing the results revealed that a positive correlation exists between path-length and particle removal rate. Thus, it was concluded that an obstacle orientation and setup leading to increased flow path-length would greatly enhance the particle removal rate and pollutant dilution. Also, regions of recirculation and stagnation proved to have a negative impact on particle removal by trapping the particles and hence should be avoided in obstacle configuration.</jats:p

Experimental Study of Mechanical Properties of Additively Manufactured ABS Plastic as a Function of Layer Parameters

In this study, a preliminary effort was undertaken to represent the mechanical properties of a 3D printed specimen as a function of layer number, thickness and raster orientation by investigating the correlation between the mechanical properties of parts manufactured out of ABS using Fused Filament Fabrication (FFF) with a commercially available 3D printer, Makerbot Replicator 2x, and the printing parameters, such as layer thickness and raster orientation, were considered. Specimen were printed at raster orientation angles of 0°, 45° and 90°. Layer thickness of 0.2 mm was chosen to print specimens from a single layer to 35 layers. Samples were tested using an MTS Universal Testing Machine with extensometer to determine mechanical strength characteristics such as modulus of elasticity, ultimate tensile strength, maximum force and maximum elongation as the number of layers increased. Results showed that 0° raster orientation yields the highest mechanical properties compared to 45° and 90° at each individual layer. A linear relationship was found between the number of layers and the maximum force for all three orientations, in other words, maximum force required to break specimens linearly increased as the number of layers increased. The results also found the elastic modulus and maximum stress to increase as the number of layers increased up to almost 12 layers. For samples with more than 12 layers, the elastic modulus and maximum stress still increased, but at a much slower rate. These results can help software developers, mechanical designers and engineers reduce manufacturing time, material usage and cost by eliminating unnecessary layers that do not increase the ultimate stress of the material by improving material properties due to the addition of layers.</jats:p