Reconsctructing The Structure And Simulating The Flow Field Of The Normal Adult's Nasal Cavity By Computer

Objective:The purpose of this trial based on the information extracted by computed tomography is to reconstruct the structure and get the detailed data of the flow fields of the normal adult's nasal cavity by the means of the finite-element method and viscous dynamics equation (Navier-Stokes equations).Material and methods: 1. Material:(1)The volunteer who think himself comfortable in the nose was an adult man, whose forepart of the nasal septum deviates to the right like the alphabet "C".(2) The multiple computed tomography machine (Germany ,Siemens Somation Volume Zoom )and legend computer were applied.2.Methods:(1)The images of the structure of the volunteer's nasal cavity were obtained through the multiple computed tomography machine.(2)The images were digitized with the Matalab software.(3)The structure of the nasal cavity was reconstructed with the preprocessor of the finite-element software package Ansys 6.1.(4)After given the boundary value, the nasal airflow profiles were simulated numerically by means of the software package Ansys 6.1 and Navier-Stokes equations.Results:1.When the velocity of the choana airflow was 3m/s,the fastest airspeed was 9.163 m/s and the minimum was –2.176 m/s (countercurrents took place in the swirling air currents)under inspiratory conditions . The maximum and minimum velocity were –9.18m/s and 1.711m/s under expiratory conditions.2. a. Simulated airflows were laminar mainly in the nasal passage and varied dramatically in the vestibule and nasopharynx.b.The maximum flow took place around the limen nsai.c.The laminar flow in the different nasal meatus varied dramatically under the inspiratory conditions and consisted with each other under the expiratory conditions. d.The airflow in the maxillary air sinus and by the maxillary hiatus was slow.e.Swirling air currents occurred in the nasopharynx, too. 3. When the velocity of the choana airflow was 4m/s, flow apportionment among different regions remained constant. The simulated velocity fields and pressure drops agreed with each other.Conclusions: The three-dimensional structure and flow field model of the nasal cavity with the computer technology of simulation could be presented, which showed the detailed data for the foundational research of the nasal flow fields.