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.