Fluid Dynamics of the Human Larynx and Upper Tracheobronchial Airways

Martonen, T. B.; Zhang, Z.; Lessmann, R. C.

doi:10.1080/02786829308959627

Cited by 66 publications

(33 citation statements)

References 48 publications

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“…These investigators used a Navier-Stokes solver but neglected the effects of turbulence. Martonen et al (1993) studied the fluid dynamics of the human larynx and upper TB airways using a numerical technique. They found that the formation of the laryngeal jet strongly affects airflow patterns in the trachea, the bifurcation zone, and the main bronchi.…”

Section: Introductionmentioning

confidence: 99%

Particle Deposition in a Cast of Human Tracheobronchial Airways

Zhou

Cheng

2005

Aerosol Science and Technology

104

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Regional particle deposition efficiency and deposition patterns were studied experimentally in a human airway replica made from an adult cadaver. The replica includes the oral cavity, pharynx, larynx, trachea, and four generations of bronchi. This study reports deposition results in the tracheobronchial (TB) region. Nine different sizes of monodispersed, polystyrene latex fluorescent particles in the size range of 0.93-30 µm were delivered into the lung cast with the flow rates of 15, 30, and 60 l min −1 . Deposition in the TB region appeared to increase with the increasing flow rate and particle size. Comparison of deposition data obtained from physical casts showed agreement with results obtained from realistic airway replicas that included the larynx. Deposition data obtained from idealized airway models or replicas showed lower deposition efficiency. We also compared experimental data with theoretical models based on a simplified bend and bifurcation model. A deposition equation derived from these models was used in a lung dosimetry model for inhaled particles, and we demonstrated that there was general agreement with theoretical models. However, the agreement was not consistent over the large range of Stokes number. The deposition efficiency was found as a function of the Stokes number, bifurcation angle, and the diameters of parent and daughter tubes. An empirical model was developed for the particle deposition efficiency in the TB region based on the experimental data. This model, combined with the oral deposition model developed previously, can be used to predict the particle deposition for inertial effects with improved accuracy.

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Section: Introductionmentioning

confidence: 99%

Particle Deposition in a Cast of Human Tracheobronchial Airways

Zhou

Cheng

2005

Aerosol Science and Technology

104

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“…The Reynolds number based on the diameter of trachea is 2400. While this Reynolds number is only slightly above the transition one, the flow in the trachea is expected to be in a low-intensity turbulence state due to the disturbances induced by the laryngeal jet formation in the glottal aperture and the vibrating vocal folds (Martonen et al 1993; West and Hugh-Jones 1959). Here, it is assumed that the incoming air has a turbulence intensity of 5% (of the mean velocity).…”

Section: Resultsmentioning

confidence: 98%

“…This model represents the cross section of the branching site of the trachea into the main bronchi in the lung of a human adult. The diameter and length of the trachea are, respectively, 1.8 and 12 cm (Martonen et al 1993). A diameter of 1.2 cm for the main bronchus and a branching angle of 45" is assumed.…”

Section: The Tracheobronchial T M Ementioning

confidence: 99%

“…Bal6sh6zy and Hofmann (1993a, b), and Bal6sh6zy (1994) analyzed the particle trajectories in a three-dimensional bronchial airway bifurcation. Martonen et al (1993Martonen et al ( , 1994 studied the fluid dynamics of the human larynx and upper tracheobronchial airways using a numerical technique. Asgharian and Anjilvel (1994) performed a numerical simulation for inertial and gravitational deposition of particles in a square cross section bifurcating passage.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, at higher flow rates unsteady flow penetrated further into the cast. Martonen et al (1993) also pointed out that the flow disturbances from the laryngeal jet would propagate into the trachea and main Bronchus.…”

Section: Introductionmentioning

confidence: 99%

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Computer Simulation of Particle Deposition in the Upper Tracheobronchial Tree

Ahmadi

1995

Aerosol Science and Technology

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A computational model for simulating particle dispersion and deposition in the human tracheobronchial tree is developed. The trachea and the main bronchi are modeled as a two-dimensional duct with two symmetric branches, and a branching angle of 45". For high inspiratory flow rates, the occurrence of turbulence in the air is considered. Using the thermodynamically consistent rate-dependent anisotropic turbulence model, the mean velocity, as well as the root-meansquare fluctuation velocity fields in the airways are evaluated. The instantaneous turbulence fluctuating velocity is simulated as a continuous Gaussian random vector field. The Brownian motion is modeled as a white noise process. The Stokes drag, the Brownian and the Saffman forces are included in the particle equation of motion. Several digital simulations for particle transport and deposition in the upper tracheobronchial airways for different breathing conditions are performed. For particles in the size range of 0.01 to 20 pm, the corresponding deposition rates on various surfaces are evaluated. The net deposition rates are compared with the available experimental data and earlier digital simulations for bifurcating tubes.

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