Aerosol particle transport and deposition in a CT-scan based mouth-throat model

© 2019 Author(s). A precise understanding of the aerosol particle transport and deposition (TD) in the realistic mouth-throat model is important for the respiratory health risk assessment and effective delivery of the aerosol medicine to the targeted positions of the lung. A wide range of studies have developed the particle TD framework for both idealized and non-idealized extra-thoracic airways. However, all of the existing in silico and experimental model reports a significant amount of aerosol particles are deposit at the extra-thoracic airways and the existing drug delivery device can deliver only 12 percent of the aerosol drug to the targeted position of the lung. This study aims to increase the efficiency of the targeted drug delivery by developing a realistic particle transport model for CT-Scan based mouth-throat replica. A 3-D realistic mouth-throat model is developed from the CT-Scan DiCom images of a healthy adult cast. High-Quality computational cells are generated for the replica model and the proper grid refinement test has been performed. ANSYS Fluent (19.1) solver is used for the particle TD computation. Tecplot and MATLAB software are used for the post-processing purpose. The numerical results report that the breathing pattern and particle diameter influences the overall particle TD in the mouth-throat model. The numerical results also depict different deposition hot spots for the mouth-throat model, which will eventually help to design a better drug delivery device. The numerical results reported that only 13.67 percent of the 10-μm diameter particles are deposited at the mouth-throat model at 15 lpm flow rate and which indicate that the remaining particles will move to the beyond airways. The present results along with more case studies will develop the understanding of the realistic particle deposition in the extrathoracic airways

Fractional electro-magneto transport of blood modeled with magnetic particles in cylindrical tube without singular kernel

The electro-kinetic transport of blood flow mixed with magnetic particles in the circular channel was investigated. The flow was subjected to an external electric and uniform magnetic field. The fluid was driven by pressure gradient and perpendicular magnetic field to the flow direction. Due to the usefulness and suitability of Caputo–Fabrizio fractional order derivative without singular kernel in fluid flow modeling and mass transfer phenomena, the governing equations were modeled as Caputo–Fabrizio time fractional partial differential equations and solved for a 2 ð0; 1�. The analytical solutions for the velocities of blood flow and magnetic particles were obtained by using Laplace, finite Hankel transforms and Robotnov and Hartley’s functions, respectively. Mathematica software was used to simulate the influences of fractional parameter a, Hartmann number and Reynolds number on the velocities of blood and magnetic particles. The findings are important for controlling bio-liquids in the devices used for analysis and diagnosis in biological and medical applications

Polydisperse Aerosol Transport and Deposition in Upper Airways of Age-Specific Lung

A comprehensive understanding of airflow characteristics and particle transport in the human lung can be useful in modelling to inform clinical diagnosis, treatment, and management, including prescription medication and risk assessment for rehabilitation. One of the difficulties in clinical treatment of lung disorders lies in the patients' variable physical lung characteristics caused by age, amongst other factors, such as different lung sizes. A precise understanding of the comparison between different age groups with various flow rates is missing in the literature, and this study aims to analyse the airflow and aerosol transport within the age-specific lung. ANSYS Fluent solver and the large-eddy simulation (LES) model were employed for the numerical simulation. The numerical model was validated with the available literature and the computational results showed airway size-reduction significantly affected airflow and particle transport in the upper airways. This study reports higher deposition at the mouth-throat region for larger diameter particles. The overall deposition efficiency (DE) increased with airway size reduction and flow rate. Lung aging effected the pressure distribution and a higher pressure drop was reported for the aged lung as compared to the younger lung. These findings could inform medical management through individualised simulation of drug-aerosol delivery processes for the patient-specific lung

CFD simulation of airflow behavior and particle transport and deposition in different breathing conditions through the realistic model of human airways

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Comparison between the volumetric flow rate and pressure distribution for different kinds of sliding thrust bearing

In this paper a hydrodynamic journal sliding bearing, forming with two nonparallel surfaces that the lower surface moves with a unidirectional velocity and the upper surface is stationary shaped with exponential geometry is verified mathematically. The values of volumetric flow rate and distribution of pressure for incompressible lubricant flow between two supports in several conditions of velocity with different variables are determined. The results indicate that by increasing the amount of constant (m), the maximum oil pressure in the bearing will face an extreme decrease, and also by increasing the α coefficient, the rate of volumetric flow rate will decrease

An analytical investigation on unsteady motion of vertically falling spherical particles in non-Newtonian fluid by Collocation Method

An analytical investigation is applied for unsteady motion of a rigid spherical particle in a quiescent shear-thinning power-law fluid. The results were compared with those obtained from Collocation Method (CM) and the established Numerical Method (Fourth order Runge–Kutta) scheme. It was shown that CM gave accurate results. Collocation Method (CM) and Numerical Method are used to solve the present problem. We obtained that the CM which was used to solve such nonlinear differential equation with fractional power is simpler and more accurate than series method such as HPM which was used in some previous works by others but the new method named Akbari-Ganji’s Method (AGM) is an accurate and simple method which is slower than CM for solving such problems. The terminal settling velocity—that is the velocity at which the net forces on a falling particle eliminate—for three different spherical particles (made of plastic, glass and steel) and three flow behavior index n, in three sets of power-law non-Newtonian fluids was investigated, based on polynomial solution (CM). Analytical results obtained indicated that the time of reaching the terminal velocity in a falling procedure is significantly increased with growing of the particle size that validated with Numerical Method. Further, with approaching flow behavior to Newtonian behavior from shear-thinning properties of flow (n → 1), the transient time to achieving the terminal settling velocity is decreased

RETRACTED: Analytical investigation of squeezing unsteady nanofluid flow between parallel plates by LSM and CM

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).This article has been retracted at the request of the Editor-in-Chief.The article duplicates significant parts of a paper that had already appeared in Powder Technology, 239 (2013) 259–265. https://doi.org/10.1016/j.powtec.2013.02.006. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper has not been previously published and is not under consideration for publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process

Heat transfer investigation of Non-Newtonian Fluid between two vertically infinite flat plates by numerical and analytical solutions

In natural convection, the fluid motion occurs by natural means such as buoyancy. Heat transfer by natural convection happens in many physical problems and engineering applications such as geothermal systems, heat exchangers, petroleum reservoirs and nuclear waste repositories. These problems and phenomena are modeled by ordinary or partial differential equations. In most cases, experimental solutions cannot be applied to these problems, so these equations should be solved using special techniques. In this paper, natural convection of a non-Newtonian fluid flow between two vertical flat plates is investigated analytically and numerically. Collocation Method (CM) and fourth-order Runge -Kutta numerical method (NUM) are used to solve the present problem. These methods are powerful and convenient algorithms in finding the solutions for the equations. While these are capable of reducing the size of calculations. In order to compare with exact solution, velocity and temperature profiles are shown graphically. The obtained results are valid with significant accuracy