Journal of Biosciences and Medicines, 2013, 1, 23-27 JBM
http://dx.doi.org/10.4236/jbm.2013.12006 Published Online October 2013 (http://www.scirp.org/journal/jbm/)
OPEN ACCESS
Characteristic size research of human nasal cavity and the
respirato ry airflow CFD analysis*
Jun Zhang
Advanced Technology of Transportation Vehicle Key Laboratory of Liaoning Province, Dalian Jiaotong University, Dalian, China
Email: armyzhang@sina.com
Received 2013
ABSTRACT
To study the airflow distribution in human nasal cav-
ity during respiration and the characteristic parame-
ters for nasal structure, thirty three-dimensional,
anatomically accurate representations of adult nasal
cavity models were reconstructed based on processed
tomography images collected from normal people.
The airflow fields in nasal cavities were simulated
using the fluid dynamics with the finite element soft-
ware ANSYS. The results showed that the difference
of human nasal cavity structure led to varying airflow
distribution in the nasal cavities and the main airflow
passed through the common nasal meatus. The nasal
resistance in the regions of nasal valve and nasal ves-
tibule accounted for more than a half of overall resis-
tance. The characteristic model of nasal cavity was
extracted based on the characteristic points and di-
mensions deducted from the original models. It
showed that either the geometric structure or the air-
flow field of the two kinds of model was similar. The
characteristic dimensions were the characteristic pa-
rameters of nasal cavity that properly represented the
original model in research for nasal cavity.
Keywords: Nasal Cavity; Characteristic Dimension;
Three-Dimensional Reconstruction ; Numerical
Simula tion of Flow Field; Computational Fluid
Dyn a mic ; Finite Element Method
1. INTRODUCTION
Nose is the first barrier of defense to outer invasions in
the human respiratory system that is protective for life
long. It provides functions of filtering, warming, and
moistening inhaled air and protects the delicate structure
of the lower respiratory system. With the current devel-
opment of research towards the pathogenic mechanism
and the application of iatrical apparatus such as endos-
copes, it has been demonstrated that certain nasal diseas-
es are closely related to the abnormal structure of nasal
cavity [1]. Some researchers have investigated the air-
flow characters in nasal cavity to try to find the corre la-
tion between the nasal structure and the nasal disease [2].
The method of numerical simulation for airflow is help-
ful to this investigation. By simulating the structure and
function of the nasal cavity with three-dimensional re-
construction theory with a computer, we can profoundly
explore the outbreak, treatment and prevention of nasal
diseases. Keyhani [3] constructed a finite element mesh
of the human nasal cavity from the CAT scans. In his
work, the steady-state N avier-Stokes and continuity equ-
ations were solved numerically to determine the laminar
airflow patterns in the nasal cavity at quiet breathing
flow rates. The numerical results were validated by com-
parison with detailed experimental measurements from
Hahn’s [4] study. Martonen [5] et al. constructed a three-
dimensional computational model of the human upper-
respiratory tract that featured both sides of nasal cavity.
The model included airways of the head and the throat
based on a cast of a medical school teaching model. The
results showed the airflow patterns in different flow rate
values and the velocity profiles during inhalation and
exhalation. Subramaniam [6] et al. represented a three-
dimensional, computational model of an adult human’s
nasal cavity and nasopharynx, and solved the Navier-
Stokes and continuity equations for airflow using the
finite-element method under conditions of steady-state
inspiratory. The model was developed from magnetic
resonance imaging scans of a person’s nose. The nasal
cavity model was divided into several regions and the
flow apportionment among different regions of the nose
was detailed. Kim [7] investigated airflows in normal
and abnormal nasal cavities and surgically created mod-
els experimentally by Particle Image Velocimetry (PIV).
The average distributions of airflow in normal and ab-
normal nasal were obtained. In the case of simulation of
surgical operations, velocity distribution in coronal sec-
tion changed locally. Reimersdahl [8] and Hörschler [9]
presented the results of numerical simulation of the air-
flow in a model of the human nasal cavity which showed
*Project of Liaoning Province Education Department, LS2010030.