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Computational Simulation of the Effect of Breathing Particle Mass and Breathing Frequency on a Human Respiratory System

Goodarzi Ardakani, Vahid | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47363 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Tayyebi Rahni, Mohammad
  7. Abstract:
  8. Our surrounding environment is full of particles with different sizes. These suspended particles enter our body through respiration process, which of course has some negative effects. Therefore, it is very important to comprehend the mechanisms and the effective parameters on these particles motion and their deposition inside the human airway. This work numerically investigates the effects of particles mass and breathing frequency on the deposition of particles in human respiratory system. To this end, a realistic 3-D model of human respiratory system geometry, including nostrils, vestibule, nasal cavity, human sinuses, nasopharynx, oropharynx, larynx, trachea, and main bronchus has been produced by reconstructing a healthy adult woman CT scan images. As far as the numerics, the Navier-Stokes equations has been used with a finite element method. Next, the air stream, motion, and deposition of the particles inside this geometry has been simulated. The effects of particles mass on their deposition for different particle diameters have been considered at micro-scale dimensions by means of aerodynamic diameter concept. Furthermore, inhalation impact, measured by experiments, has been applied by utilization of a UDF in the ANSYS FLUENT commercial software for semi sinusoidal profile. Also, particle pathlines have been computed, using a Lagrangian approach. In addition, results for unsteady solution under appropriate conditions have been validated with valid experimental data. Our results show that the diffusion mechanism for the particles with diameter less than 1 micrometer is dominant. Also, by increasing aerodynamic diameter, corresponding to the mass particle increment, particle deposition increases due to inertial impaction mechanism. The deposition process continues up to the point when all 10 micrometer particles deposit at the upper respiratory track. The results show that the amount of remaining particles in the flow at steady state condition is more than that in the unsteady case
  9. Keywords:
  10. Numerical Simulation ; Respiratory System ; Particle Deposition ; Inspiration

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