Numerical Simulation For Airflow In The Nasal Cavity With Deviated Nasal Septum

Nasal septum deviation is frequently encountered disease with septum morphological variation. Nasal anatomical anomaly and self-adaptation cause the nasal structural change which influences the normal physiology function. However, quantificational investigation of the airflow state and distribution in the nasal cavity is so difficult for complicated three-dimensional structure. The further studies of diseases with deviated nasal septum are limited. So it's necessary to study the airflow state of cavity with deviated nasal septum by biomechanical approaches.Based on the detail anatomic data and CT data of cavity with deviated nasal septum, three-dimensional nasal cavity models are reconstructed using the method of surface reconstruction. The numerical simulations of flow field in cavity models are obtained by finite element method. The airflow and pressure distribution during respiratory cycle are numerically simulated using finite element method and compared with healthy nasal cavity.Air distributions of high-speed in nasal cavity with deviated nasal septum are different on each side. Based on the degree of change of structural self-adaptation, flow rate distribution is divided into two classes. If the side opposite to the deviated septum dose not have the apparent turbinate hyperplasia, the airflow mainly passes the middle medial regions of the nasal meatus in the opposite side of deviation; If the side opposite to the deviated septum has the apparent turbinate hyperplasia, the airflow mainly passes the inferior medial regions of the nasal meatus in the deviated side. Nasal resistance in two side of nasal cavity is different. In the most of nasal cavities with deviated nasal septum flow-limiting segment of the cavity are not in the region of limen nasi. They move to the region of fore stand middle turbinate.Results of numerical simulation of cavity with deviated nasal septum are presented and compared with data from healthy nasal cavities. And it could quantificational display the influence of deflected nasal septum and self-adaptation on airflow distribution. The results of the numerical simulation are useful for studying the pathogenesis and diagnosing the disease which relate to the deflected nasal septum.The research work in this paper is a part of National Natural Science foundation of China (10472025; 10672036).