Publication detail

Characteristics of Turbulent Particle Transport in Human Airways under Steady and Cyclic Flows

JEDELSKÝ, J. LÍZAL, F. JÍCHA, M.

Original Title

Characteristics of Turbulent Particle Transport in Human Airways under Steady and Cyclic Flows

English Title

Characteristics of Turbulent Particle Transport in Human Airways under Steady and Cyclic Flows

Type

journal article in Web of Science

Language

en

Original Abstract

Motion of monodispersed micron-sized particles suspended in air flow was studied on transparent model of human airways using Phase-Doppler Particle Analyser (P/DPA). Time-resolved velocity data for particles in size range 1 to 8 um were processed using Fuzzy Slotting Technique embedded in Kern software (Nobach, 2002) to estimate power spectral density (PSD) of velocity fluctuations. Optimum setup of the software for these data was found and recommendations for improvements of future experiments were given. Typical PSD plots are documented and mainly differences among (1) steady-flow regimes and analogous cyclic breathing regimes, (2) inspiration and expiration breathing phase and (3) behaviour of particles with different size are described for several different positions in the airway model. Systematically higher content of velocity fluctuations in the upper part of frequency range (30 to 500 Hz) was found for cyclic flows in comparison with corresponding steady flows. Expiratory flows in both the (steady and cyclic) cases produce more high-frequency fluctuations compared to inspiratory flows. Negligible differences were found for flow of particles in the inspected size range 1 to 8 um at frequencies up to 500 Hz. This finding was explained by Stokes number analysis. Implied match of the air and particle flows thereby confirms a possibility to use the P/DPA data as air flow velocity estimate.

English abstract

Motion of monodispersed micron-sized particles suspended in air flow was studied on transparent model of human airways using Phase-Doppler Particle Analyser (P/DPA). Time-resolved velocity data for particles in size range 1 to 8 um were processed using Fuzzy Slotting Technique embedded in Kern software (Nobach, 2002) to estimate power spectral density (PSD) of velocity fluctuations. Optimum setup of the software for these data was found and recommendations for improvements of future experiments were given. Typical PSD plots are documented and mainly differences among (1) steady-flow regimes and analogous cyclic breathing regimes, (2) inspiration and expiration breathing phase and (3) behaviour of particles with different size are described for several different positions in the airway model. Systematically higher content of velocity fluctuations in the upper part of frequency range (30 to 500 Hz) was found for cyclic flows in comparison with corresponding steady flows. Expiratory flows in both the (steady and cyclic) cases produce more high-frequency fluctuations compared to inspiratory flows. Negligible differences were found for flow of particles in the inspected size range 1 to 8 um at frequencies up to 500 Hz. This finding was explained by Stokes number analysis. Implied match of the air and particle flows thereby confirms a possibility to use the P/DPA data as air flow velocity estimate.

Keywords

Aerosol, Human airway model, Power spectral density, Velocity fluctuations, Stokes number, Steady flows, Cyclic flows, Laser Doppler Anemometry

RIV year

2012

Released

15.06.2012

Publisher

Elsevier

Location

Oxford, United Kingdom

Pages from

84

Pages to

92

Pages count

9

URL

Full text in the Digital Library

BibTex


@article{BUT99351,
  author="Jan {Jedelský} and František {Lízal} and Miroslav {Jícha}",
  title="Characteristics of Turbulent Particle Transport in Human Airways under Steady and Cyclic Flows",
  annote="Motion of monodispersed micron-sized particles suspended in air flow was studied on transparent model of human airways using Phase-Doppler Particle Analyser (P/DPA). Time-resolved velocity data for particles in size range 1 to 8 um were processed using Fuzzy Slotting Technique embedded in Kern software (Nobach, 2002) to estimate power spectral density (PSD) of velocity fluctuations. Optimum setup of the software for these data was found and recommendations for improvements of future experiments were given. Typical PSD plots are documented and mainly differences among (1) steady-flow regimes and analogous cyclic breathing regimes, (2) inspiration and expiration breathing phase and (3) behaviour of particles with different size are described for several different positions in the airway model. Systematically higher content of velocity fluctuations in the upper part of frequency range (30 to 500 Hz) was found for cyclic flows in comparison with corresponding steady flows. Expiratory flows in both the (steady and cyclic) cases produce more high-frequency fluctuations compared to inspiratory flows. Negligible differences were found for flow of particles in the inspected size range 1 to 8 um at frequencies up to 500 Hz. This finding was explained by Stokes number analysis. Implied match of the air and particle flows thereby confirms a possibility to use the P/DPA data as air flow velocity estimate.",
  address="Elsevier",
  chapter="99351",
  doi="10.1016/j.ijheatfluidflow.2012.01.003",
  institution="Elsevier",
  number="35",
  volume="2012",
  year="2012",
  month="june",
  pages="84--92",
  publisher="Elsevier",
  type="journal article in Web of Science"
}