deposition of colloidal Particles onto surfaces is usually assumed to follow the Derjaguin-Landau- Verwey-Overbeek (D.L.V.O.) theory for colloidal stability. In the work presented here the D.L.V.O theory is extended to include the case where the surface is electronically conducting. The effect of application of an electric field to the surfaces on the rate of deposition of 5.4 µm colloidal Particles is simulated.

In this study, using a 5-lobe symmetric model, total, lobar and generational Particle deposition in the lungs during successive cycles is investigated. It has been found that for the Particle size between 0. 05 and 2 μ m and the tidal volumes greater than 1000 ml, considering the effect of successive cycles predicted more deposition fraction per cycle compared to a single cycle up to about 16 percent. The mentioned range of tidal volume is related to light or heavy physical activities. So, it can be understood that people exposed to particulate matter within the mentioned size range, when acting physically, are at more health risk compared not only to the resting state, but also to the same state calculations based on a single cycle. Finally, total and generational remaining mass fraction suspended in the respiratory tract after the completion of each cycle is calculated. This remaining mass fraction turned out to be negligible except for Particles between 0. 05 and 2 μ m.

To gain insights into ink material deposition behavior during Aerosol Jet® printing, Particle deposition patterns on the plate of inertial impactor with circular laminar jet are investigated numerically with a lagrangian solver implemented within the framework of the OpenFOAM® CFD package. Effects of taper angle of the nozzle channel and jet-to-plate distance are evaluated. The results show quite different Particle deposition patterns between tapered nozzle and straight nozzle. At jet Reynolds number Re = 1132, a tapered nozzle deposits Particles to form a pattern with a high density ring toward the deposition spot edge, especially when the Particle Stokes number St > St50, which is absent with a straight nozzle. Increasing the jet-to-plate distance tends to reduce such Particle density peak. Reducing Re to 283 yields Particle deposition patterns without the high density ring near the spot edge, with the same tapered nozzle. The Particle deposition patterns with the straight nozzle at Re = 283 exhibit further reduced Particle density around the spot edge such that the Particle density profile appears more like a Gaussian function. In general, the effect of reducing Re on Particle deposition pattern seems to be similar to increasing the jet-to-plate distance. The computed Particle deposition efficiency η shows the fact that those Particles around the jet axis, even with very small values of St, always impact the center of plate, as indicated by the nonvanishing value of η with substantial reduction of St. Such a “ small Particle contamination” typically amounts to ~10% of small Particles (with St < 0. 1) at Re ~ 1000 and ~5% at Re ~ 300, which may not be negligible in data analysis with inertial impactor measurement.

Airflow simulation of the whole respiratory system is still unfeasible due to the geometrical complexity of the lung airways and the diversity of the length scales involved in the problem. Even the new CT imaging system is not capable of providing accurate 3D geometries for smaller tubes, and a complete 3D simulation is impeded by the limited computational resources available. The aim of this study is to develop a fully coupled 3D-1D model to make accurate prediction of airflow and Particle deposition in the whole respiratory track, with reasonable computational cost and efficiency. In the new proposed method, the respiratory tree is divided into three parts to be dealt with using different models. A three dimensional model is used to compute the airflow in the upper part of the tree, while the distal part is studied using a 1D model. A lumped model is also used for the acinar region. The three models are coupled together by implementing the physical boundary conditions at the model interfaces. In the end, this multiscale model is used to find the deposition pattern of Particles within a sample lung.

Design of an electrochemical adsorption cell utilising Reticulated Vitreous Carbon [RVC] as the working electrode, stainless steel as the counter electrode and a cellulose acetate membrane separator for the sepa ration of 5.4 m on polystyrene latex colloidal Particles from a KCI solution is described. Effect of variation of flow rate and electrolyte concentration on the rate of deposition is investigated and the results are compared with Derjaguin-Landau- Verwey-Overbeek [DLVO] predictions for the occurrence of favorable and unfavorable deposition conditions.

This work investigates the turbulent flow and Particles deposition in wavy duct flows. The v2f turbulence model was used for simulating the turbulent flow through the wavy channel. The instantaneous turbulence fluctuating velocities were simulated using the Kraichnan Gaussian random field model. For tracking Particles in the fluid flow, the Particle equation of motion was solved numerically. The drag, Saffman lift, Brownian, and gravity forces acting on a suspended Particle were included in the Particle equation of motion. The effects of duct wave amplitude and wave length on deposition of Particles of different sizes were studied. A range of waves with different amplitudes and wave lengths were simulated. The Particle tracking approach was validated for turbulent flow in a flat horizontal channel where good agreement with previous studies was found. The presented results showed that the duct wavy walls significantly increase the Particle deposition rate.

The nasal cavity and sinuses are a component of the upper respiratory system and study the air passage into the upper component of human airway is consequential to amend or remedy deficiency in human respiration cycle. The nose performs many paramount physiological functions, including heating, humidifying and filtering inspired air, as well as sampling air to smell. Aforetime, numerical modeling of turbulent flow in authentic model of nasal cavity, sinus, pharynx and larynx has infrequently been employed. This research has tried to study details of turbulent airflow and Particle deposition through all spaces in three-dimensional authentic model of human head which is obtained from computed tomography scan images of a 26-years old female head, neck and chest without any problem in her respiratory system that air can flow them. The Particle size in this study was opted to be in the range of 5-30 μ m. The Particles are tracked through the continuum fluid discretely utilizing the Lagrangian approach.