New and Updated Models, Apps, and Add-ins in Version 6.4
Turbulent Aggregation of Nanoparticles
Nanoparticles have become widely used in a range of applications. For example, in pharmaceuticals, particles on the nanoscale, such as nanocrystals, are often used as an effective means of drug delivery. This model solves for the turbulent aggregation of particles in the range of a few hundred nanometers in a beaker fitted with a square blade impeller in order to predict the evolution of the size distribution.
Chemical Vapor Deposition of Titanium Nitride on Machining Tool Inserts
Machining tools are often coated with titanium nitride (TiN) to improve their wear resistance, reduce friction, and decrease their oxidation. This model simulates the process of coating metal inserts with TiN through chemical vapor deposition (CVD). The system studied consists of a horizontal tray in a cylindrical CVD reactor. A gas containing titanium chloride (TiCl4) is fed into the system at the center of the reactor, flowing over the inserts placed on the tray and exiting the system through openings in the outer reactor wall. The titanium chloride in the feed gas reacts with nitrogen in the gas phase to form solid TiN that deposits on the inserts. The model considers fluid flow and mass transfer in the gas phase together with the buildup of solid TiN on the inserts. Both the deposition rate and the solid layer buildup are analyzed as a function of time. With the aim of minimizing the variation of the solid layer thickness, the impact of rotating the inserts is also investigated.
Charging of a Metal Hydride Tank
Metal hydride tanks offer safe hydrogen storage, thanks to their low reactivity, and a relatively high hydrogen density. When developing metal hydride tanks, modeling and simulation is useful for optimizing operating conditions, such as gas composition, pressure, and temperature, based on specific design parameters like metal composition, porosity, and geometric dimensions.
In this example, the charging process of a metal hydride tank is described. It includes the thermodynamics and absorption kinetics and computes the flow, concentrations, and temperature fields.
Convective Evaporation of a Water–Acetone Droplet
In this model, the evaporation of a water–acetone droplet on a marble substrate is studied in detail. The droplet consists of a concentrated aqueous solution that initially contains 20% acetone by weight. The model describes the coupled phenomena of mass and heat transfer across the vapor–liquid interface and accounts for multiphase flow by solving for the velocity in both the vapor and the liquid. As the droplet evaporates, the model tracks the position of the vapor–liquid interface.
Practical applications where detailed modeling of evaporation is valuable are found in a wide range of industries such as the pharmaceutical industry, fine chemicals production, and other industries where separation and drying processes need to be investigated.