Studie cyklického a stacionárního pohybu částic v realistickém modelu dýchacího traktu člověka pomocí fázové dopplerovské anemometrie

Study of cyclic and steady particle motion in a realistic human airway model using phase-Doppler anemometry

článek ve sborníku ve WoS nebo Scopus

en

Transport and deposition of particles in human airways has been of research interest for many years. Various experimental methods such as constant temperature anemometry, particle image velocimetry and laser-Doppler based techniques were employed for study of aerosol transport in the past. We use Phase-Doppler Particle Analyser (P/DPA) for time resolved size and velocity measurement of liquid aerosol particles in a size range 1 to 8 um. The di-2-ethylhexyl sabacate (DEHS) particles were produced by condensation monodisperse aerosol generator. A thin-wall transparent model of human airways with non-symmetric bifurcations and non-planar geometry containing parts from throat to 3rd-4th generation of bronchi was fabricated for the study. Several cyclic (sinusoidal) breathing regimes were simulated using pneumatic breathing mechanism. Analogous steady-flow regimes were also investigated and used for comparison. An analysis of the particle velocity data was performed with aim to gain deeper understanding of the transport phenomena in the realistic bifurcating airway system. Flows of particles of different sizes in range 1-10 um was found to slightly differ for extremely high Stokes numbers. Differences in steady and cyclic turbulence intensities were documented in the paper. Systematically higher turbulence intensity was found for cyclic flows and mainly in the expiration breathing phase. Negligible differences were found for behaviour of different particle size classes in the inspected range 1 to 8 um. Possibility of velocity spectra estimation of air flow using the P/DPA data is discussed.

Rostoucí zájem o znalost transportu aerosolu v lidských plicích souvisí s aplikacemi inhalovaných farmaceutik. Průhledný realistický model dýchacích cest člověka s nesymetrickým větvením a prostorovou geometrií obsahující části od hrdla až třetí-čtvrté generace bronchů byl použit pro studium transportu kapalných aerosolových částic s pomocí fázové dopplerovské anemometrie. Rychlost částic o velikosti v rozsahu 1 do 8 mikronů byla měřena při ustálených a cyklických podmínkách proudění pomocí fázového Dopplerovského analyzátoru. Byly nalezeny určité rozdíly v pohybu větších a menších částic a významné rozdíly mezi pohybem částic při ustálených a cyklických podmínkách proudění. V článku jsou dokumentovány konkrétní případy proudění ve formě časových záznamů a frekvenčních spekter.

Transport and deposition of particles in human airways has been of research interest for many years. Various experimental methods such as constant temperature anemometry, particle image velocimetry and laser-Doppler based techniques were employed for study of aerosol transport in the past. We use Phase-Doppler Particle Analyser (P/DPA) for time resolved size and velocity measurement of liquid aerosol particles in a size range 1 to 8 um. The di-2-ethylhexyl sabacate (DEHS) particles were produced by condensation monodisperse aerosol generator. A thin-wall transparent model of human airways with non-symmetric bifurcations and non-planar geometry containing parts from throat to 3rd-4th generation of bronchi was fabricated for the study. Several cyclic (sinusoidal) breathing regimes were simulated using pneumatic breathing mechanism. Analogous steady-flow regimes were also investigated and used for comparison. An analysis of the particle velocity data was performed with aim to gain deeper understanding of the transport phenomena in the realistic bifurcating airway system. Flows of particles of different sizes in range 1-10 um was found to slightly differ for extremely high Stokes numbers. Differences in steady and cyclic turbulence intensities were documented in the paper. Systematically higher turbulence intensity was found for cyclic flows and mainly in the expiration breathing phase. Negligible differences were found for behaviour of different particle size classes in the inspected range 1 to 8 um. Possibility of velocity spectra estimation of air flow using the P/DPA data is discussed.

cyklické a stacionární proudění, pohyb částic, realistický model dýchacího traktu člověka, fázová dopplerovská anemometrie

cyclic and steady flow, particle motion, realistic human airway model, phase-doppler anemometry

2010

24.11.2010

EDP Sciences

Liberec

978-80-7372-670-6

2100-014X

International conference Experimental Fluid Mechanics 2010 Conference Proceedings Volume 1

25

1

1

252–262

11