Detail publikace

Numerické vyšetřování proudění během nádechu v realistickém modelu horní části dýchacího traktu a jeho srovnání s experimenty

ELCNER, J. LÍZAL, F. JEDELSKÝ, J. JÍCHA, M. CHOVANCOVÁ, M.

Originální název

Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results

Český název

Numerické vyšetřování proudění během nádechu v realistickém modelu horní části dýchacího traktu a jeho srovnání s experimenty

Anglický název

Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results

Typ

článek v časopise

Jazyk

en

Originální abstrakt

In this article, the results of numerical simulations using computational fluid dynamics (CFD) and a comparison with experiments performed with phase Doppler anemometry are presented. The simulations and experiments were conducted in a realistic model of the human airways, which comprised the throat, trachea and tracheobronchial tree up to the fourth generation. A full inspiration/expiration breathing cycle was used with tidal volumes 0.5 and 1 L, which correspond to a sedentary regime and deep breath, respectively. The length of the entire breathing cycle was 4 s, with inspiration and expiration each lasting 2 s. As a boundary condition for the CFD simulations, experimentally obtained flow rate distribution in 10 terminal airways was used with zero pressure resistance at the throat inlet. CCM+ CFD code (Adapco) was used with an SST k-ω low-Reynolds Number RANS model. The total number of polyhedral control volumes was 2.6 million with a time step of 0.001 s. Comparisons were made at several points in eight cross sections selected according to experiments in the trachea and the left and right bronchi. The results agree well with experiments involving the oscillation (temporal relocation) of flow structures in the majority of the cross sections and individual local positions. Velocity field simulation in several cross sections shows a very unstable flow field, which originates in the tracheal laryngeal jet and propagates far downstream with the formation of separation zones in both left and right airways. The RANS simulation agrees with the experiments in almost all the cross sections and shows unstable local flow structures and a quantitatively acceptable solution for the time-averaged flow field.

Český abstrakt

V tomto článku jsou publikovány výsledky srovnání numerické simulace provedené metodou výpočtové mechaniky kontinua (CFD) a experimentů provedených za využití fázové Dopplerovské anemometrie. Simulace a experimenty byly provedeny na totožné, realistické geometrii dýchacích cest, která sestávala z hrdla, trachey a bronchiálního stromu do čtvrté generace větvení. Plný dýchací cyklus (nádech/výdech) byl uvažován při dechových objemech 0,5 a 1 l, které odpovídají klidovému režimu a hlubokému nádechu. Celý dýchací cyklus trval 4 sekundy, kdy délka vdechové a výdechové části činila vždy 2 sekundy. Jako okrajová podmínka pro CFD simulace byla použita data naměřená během experimentů na deseti zakončeních bronch. stromu a nulový tlakový tlakový odpor na vstupu do hrdla modelu. Výpočty byly provedeny v komerčním CFD programu Star-CCM+ (CD-Adapco) za použití SST k-ω low-Reynolds Number RANS modelu turbulence. Celkový počet polyhedrálních buněk byl 2,6 milionu a délka časového kroku činila 0,001 s. Porovnání bylo provedeno v několika bodech ležících v osmi řezech vybraných na základě experimentů v trachei a levém a pravém bronchu. Výsledky ve většině řezů i jednotlivých bodech vykazují dobrou shodu s experimenty. Nasimulovaná rychlostní pole v některých řezech vykazují velmi nestabilní tvar proudění, jehož původcem je laryngální proud, které je promítnuto hluboko do bronchiálního stromu, kde formuje místa odtržení. Simulace provedená metodou RANS je v souladu s experimenty téměř ve všech řezech a ukazuje nestabilitu lokálních proudových struktur a kvantitativně přijatelné řešení pro časově průměrované proudové pole.

Anglický abstrakt

In this article, the results of numerical simulations using computational fluid dynamics (CFD) and a comparison with experiments performed with phase Doppler anemometry are presented. The simulations and experiments were conducted in a realistic model of the human airways, which comprised the throat, trachea and tracheobronchial tree up to the fourth generation. A full inspiration/expiration breathing cycle was used with tidal volumes 0.5 and 1 L, which correspond to a sedentary regime and deep breath, respectively. The length of the entire breathing cycle was 4 s, with inspiration and expiration each lasting 2 s. As a boundary condition for the CFD simulations, experimentally obtained flow rate distribution in 10 terminal airways was used with zero pressure resistance at the throat inlet. CCM+ CFD code (Adapco) was used with an SST k-ω low-Reynolds Number RANS model. The total number of polyhedral control volumes was 2.6 million with a time step of 0.001 s. Comparisons were made at several points in eight cross sections selected according to experiments in the trachea and the left and right bronchi. The results agree well with experiments involving the oscillation (temporal relocation) of flow structures in the majority of the cross sections and individual local positions. Velocity field simulation in several cross sections shows a very unstable flow field, which originates in the tracheal laryngeal jet and propagates far downstream with the formation of separation zones in both left and right airways. The RANS simulation agrees with the experiments in almost all the cross sections and shows unstable local flow structures and a quantitatively acceptable solution for the time-averaged flow field.

Rok RIV

2015

Vydáno

12.07.2015

Nakladatel

Springer Berlin Heidelberg

Místo

Berlin

Strany od

1

Strany do

23

Strany počet

23

URL

BibTex


@article{BUT117291,
  author="Jakub {Elcner} and František {Lízal} and Jan {Jedelský} and Miroslav {Jícha} and Michaela {Chovancová}",
  title="Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results",
  annote="In this article, the results of numerical simulations using computational fluid dynamics (CFD) and a comparison with experiments performed with phase Doppler anemometry are presented. The simulations and experiments were conducted in a realistic model of the human airways, which comprised the throat, trachea and tracheobronchial tree up to the fourth generation. A full inspiration/expiration breathing cycle was used with tidal volumes 0.5 and 1 L, which correspond to a sedentary regime and deep breath, respectively. The length of the entire breathing cycle was 4 s, with inspiration and expiration each lasting 2 s. As a boundary condition for the CFD simulations, experimentally obtained flow rate distribution in 10 terminal airways was used with zero pressure resistance at the throat inlet. CCM+ CFD code (Adapco) was used with an SST k-ω low-Reynolds Number RANS model. The total number of polyhedral control volumes was 2.6 million with a time step of 0.001 s. Comparisons were made at several points in eight cross sections selected according to experiments in the trachea and the left and right bronchi. The results agree well with experiments involving the oscillation (temporal relocation) of flow structures in the majority of the cross sections and individual local positions. Velocity field simulation in several cross sections shows a very unstable flow field, which originates in the tracheal laryngeal jet and propagates far downstream with the formation of separation zones in both left and right airways. The RANS simulation agrees with the experiments in almost all the cross sections and shows unstable local flow structures and a quantitatively acceptable solution for the time-averaged flow field.",
  address="Springer Berlin Heidelberg",
  chapter="117291",
  doi="10.​1007/​s10237-015-0701-1",
  howpublished="online",
  institution="Springer Berlin Heidelberg",
  number="2",
  volume="15",
  year="2015",
  month="july",
  pages="1--23",
  publisher="Springer Berlin Heidelberg",
  type="journal article"
}