Abstract/Details

Numerical analysis of respiratory aerosol deposition: Effects of exhalation, airway constriction and electrostatic charge


2008 2008

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Abstract (summary)

The dynamics of particle laden flows are integral to the analysis of toxic particle deposition and medical respiratory aerosol delivery. Computational fluid-particle dynamics (CFPD) can play a critical role in developing a better understanding of particle laden flows, especially in a number of under-explored areas. The applications considered in this study include both the numerical aspects and the physical phenomena of respiratory aerosol transport. Objective I: Considering the effects of mesh type and grid convergence, four commonly implemented mesh styles were applied to a double bifurcation respiratory geometry and tested for flow patterns and aerosol deposition. Results indicated that the mesh style employed had a significant effect on the transport and deposition of aerosols with hexahedral meshes being most accurate. Objective II: In order to evaluate the effects of bronchoconstriction under exhalation conditions, normal and constricted pediatric airway models were considered. Results include (i) a significant increase in deposition for constricted airways, and (ii) a novel correlation for deposition during exhalation based on the Dean and Stokes numbers. Objective IIIa: Considering evaluation of an aerosol size sampler, an eight-stage Andersen cascade impactor (ACI) was numerically analyzed. The numerical simulations indicated high non-uniformity and recirculation in the flow field. Numerical predictions of retention fraction matched well with existing experiments (0.5–11% error). Objective IIIb: As an extension, numerical predictions of electrostatic charge effects on aerosol transport and deposition in the ACI were evaluated. Charges consistent with standard pharmaceutical pressurized metered dose inhalers and dry powder inhalers were considered. The numerical predictions indicated that charged aerosols deposit as if they were 5–85% larger due to electrostatic effects. Applications of the studies considered include (i) quantitative guidance in selecting numerical mesh styles and development of standard grid convergence criteria, (ii) the development of more accurate whole-lung deposition models that better evaluate exhalation conditions, (iii) improvements in the design of pharmaceutical assessment and delivery devices, and (vi) correction values to account for the effect of electrostatic charge on size measurements of pharmaceutical aerosols.

Indexing (details)


Subject
Biomedical engineering;
Mechanical engineering
Classification
0541: Biomedical engineering
0548: Mechanical engineering
Identifier / keyword
Applied sciences; Aerosol deposition; Airway constriction; Electrostatic charge; Exhalation; Respiratory aerosols
Title
Numerical analysis of respiratory aerosol deposition: Effects of exhalation, airway constriction and electrostatic charge
Author
Vinchurkar, Samir C.
Number of pages
235
Publication year
2008
Degree date
2008
School code
2383
Source
DAI-B 69/10, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780549866770
Advisor
Longest, P. Worth
University/institution
Virginia Commonwealth University
University location
United States -- Virginia
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3334079
ProQuest document ID
304841125
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304841125
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