The effect on regional lung deposition of coupled heat and mass transfer between hygroscopic droplets and their surrounding phase

Finlay, Warren H.; Stapleton, K.W.

doi:10.1016/0021-8502(94)00132-i

Cited by 81 publications

(52 citation statements)

References 22 publications

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“…However, in many situations, solid or liquid particles undergo size changes because they absorb moisture or to lose mass from their surfaces due to condensation or evaporation (i.e., hygroscopity). The effect of hygroscopity on deposition fraction in the human respiratory system has been investigated experimentally and theoretically (e.g., Broday and Georgopoulos 2001;Ferron et al 1988Ferron et al , 1989Finlay and Stapleton 1995;Gebhart et al 1990;Hickey and Martonen 1991;Morrow 1986). For example, hygroscopity can substantially increase the size and hence the airway deposition fraction of drug particles with initial dry sizes of about 0.5-2 µm (Ferron et al 1989).…”

Section: Introductionmentioning

confidence: 99%

Vaporizing Microdroplet Inhalation, Transport, and Deposition in a Human Upper Airway Model

Zhang¹,

Kleinstreuer²,

Kim³

et al. 2004

Aerosol Science and Technology

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Evaluation of injuries from inhalation exposure to toxic fuel requires detailed knowledge of inhaled aerosol transport and deposition in human airways. Focusing on highly toxic, easily volatized JP-8 fuel droplets, the three-dimensional airflow, temperature distributions, and fluid-particle thermodynamics, i.e., droplet motion as well as evaporation, are simulated and analyzed for laminar as well as locally turbulent flow conditions. Specifically, using a commercial finite-volume software with user-supplied programs as a solver, the Euler-Lagrange approach for the fluid-particle thermodynamics is employed with: (1) a low Reynolds number k-ω model for laminar-to-turbulent airflow, and (2) a stochastic model for random fluctuations in the droplet trajectories with droplet evaporation. Presently, the respiratory system consists of two major segments of a simplified human cast replica, i.e., a representative oral airway from mouth to trachea (Generation 0) and a symmetric four-generation upper bronchial tree model (G0 to G3). Experimentally validated computational fluid-particle thermodynamics results show that evaporation of JP-8 fuel droplets is greatly affecting deposition in the human airway. Specifically, droplet deposition fractions due to vaporization Address correspondence to Clement Kleinstreuer, Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, USA. E-mail: ck@eos.ncsu.edu decrease with increasing ambient temperatures and decreasing inspiratory flow rates. It is also demonstrated that assuming idealized velocity profiles and particle distributions in or after the trachea may greatly overpredict particle deposition efficiencies in the upper bronchial tree.

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Section: Introductionmentioning

confidence: 99%

Vaporizing Microdroplet Inhalation, Transport, and Deposition in a Human Upper Airway Model

Zhang¹,

Kleinstreuer²,

Kim³

et al. 2004

Aerosol Science and Technology

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“…The modelling of deposition of inhaled aerosols over the years has evolved from simple and limited algebraic models (James et al (1991)) to more complex and accurate empirical (Martonen et al (1994)), one-way coupled (Ferron et al (1988)), and two-way coupled hygroscopic models (Finlay & Stapleton (1995)), based on the Lagrangian approach. All these models treat the lung as unidimensional, calculating deposition on a typical or average aerosol path.…”

Section: Modelling Drug Deposition In the Lungmentioning

confidence: 99%

“…cit., Fig. 9): subject 1 and d a =7.5 µm, subject 4 and d a =7.3 µm) were calculated with the 1-D deposition model from Finlay & Stapleton (1995), using the lung geometry dimensions from Finlay (2001). Note that the length of the trachea was shortened by 3 cm, because of the way the tracheobronchial region was imaged in Stahlhofen et al (1980).…”

Section: Mucus Clearance Velocitymentioning

confidence: 99%

Improving the Likelihood of Success in Trials and the Efficiency of Delivery of Mucolytics and Antibiotics

Lange¹

2012

Cystic Fibrosis - Renewed Hopes Through Research

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“…The second expected effect of dense cigarette smoke is a limit to the amount of water vapor that is available for absorption on the particles. As a result, condensational growth may be rate limited due to the rapid removal of water vapor, as described in detail by Finlay (1998) and Finlay and Stapleton (1995). Therefore, the assumption of a dilute one-way coupled discrete phase is used in this study to isolate condensation effects and to approximate the maximum possible growth due to condensation for initially monodisperse particles.…”

Section: Flow Rates and Boundary Conditionsmentioning

confidence: 99%

Condensational Growth May Contribute to the Enhanced Deposition of Cigarette Smoke Particles in the Upper Respiratory Tract

Longest

2008

Aerosol Science and Technology

113

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Previous experimental studies have shown that concentrated cigarette smoke particles (CSPs) deposit in the upper airways like much larger 6 to 7 µm aerosols. Based on the frequent assumption that relative humidity (RH) in the lungs does not exceed approximately 99.5%, the hygroscopic growth of initially submicrometer CSPs is expected to be a relatively minor factor. However, the inhalation of mainstream smoke may result in humidity values ranging from sub-saturated through supersaturated conditions. The objective of this study is to evaluate the effect of condensation particle growth on the transport and deposition of CSPs in the upper respiratory tract under various RH and temperature conditions. To achieve this objective, a computational model of transport in the continuous phase surrounding a CSP was developed for a multicomponent aerosol consisting of water soluble and insoluble species. To evaluate the transport and deposition of dilute hygroscopic CSPs in the upper airways, a model of the human mouththroat (MT) through approximately respiratory generation G6 was considered with four steady inhalation conditions. These inhalation conditions were representative of inhaled ambient cigarette smoke as well as warm and hot saturated smoke. Results indicate that RH conditions above 100% are possible in the upper respiratory tract during the inhalation of a warm or hot saturated airstream. For sub-saturated inhalation conditions, initial evaporation of the CSPs was observed followed by hygroscopic growth and diameter increases less than approximately 50%. In contrast, the inhalation of warm or hot saturated air resulted in significant particle growth in the MT and tracheobronchial regions. For the inhalation of warm saturated air 3• C above body temperature, initially 200 and 400 nm particles were observed to increase in size to above 3 µm near the trachea inlet. The upper boundary inhalation condition • C air resulted in 7 to 8 µm droplets entering the trachea. These results do not prove that the enhanced deposition of CSPs in the upper airways is only a result of condensational growth. However, this study does highlight condensational growth as a potentially significant mechanism in the deposition of smoke particles under saturated inhalation conditions. INTRODUCTIONRelationships between cigarette smoke constituents and lung disease, respiratory and systemic cancer, and cardiovascular disease have been well established (Doll and Hill 1950;Wynder and Graham 1950; WHO 2002; U.S. Department of Health and Human Services 2004;. Considering bronchogenic carcinoma, a number of studies have reported evidence linking local sites of deposited cigarette smoke particles (CSPs) with disease formation (Bryson and Spencer 1951;Ermala and Holsti 1955;Martonen 1986;Martonen et al. 1987;Yang et al. 1989). For example, Yang et al. (1989) reported significantly elevated incidents of bronchogenic carcinoma at sites that coincided with previously observed CSP deposition from other studies (Bryson and Spencer 1951;Ermala and Holsti 1...

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The effect on regional lung deposition of coupled heat and mass transfer between hygroscopic droplets and their surrounding phase

Cited by 81 publications

References 22 publications

Vaporizing Microdroplet Inhalation, Transport, and Deposition in a Human Upper Airway Model

Vaporizing Microdroplet Inhalation, Transport, and Deposition in a Human Upper Airway Model

Improving the Likelihood of Success in Trials and the Efficiency of Delivery of Mucolytics and Antibiotics

Condensational Growth May Contribute to the Enhanced Deposition of Cigarette Smoke Particles in the Upper Respiratory Tract

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