| Nasal cavity is the portal of human respiratory system that serves as the front of main breathing passage of human beings. Besides respiratory, it provides the functions to filters, warms, and humidifies inspired air and protects the delicate structure of the lower respiratory system as while. Organs inside nasal cavity can remodel its shape duel to the change of outer stimulus such as airflow velocity, pressure and so on. The process of remodeling is called self adaptation. With the current development of research towards the pathogenic mechanism and the application of iatrical apparatus such as endoscopes, it has been demonstrated that some nasal diseases are closely related to the abnormal structure of nasal cavity and the anatomical change of the nasal cavity may lead to many diseases, among which the DNS is regular and is widely found in the world. But because of the lack of proper biomechanical model and its numerical description for the course of adaptation, it is difficult to deeply explore and explain this process.Recently, computer aided design and numerical simulation together with theoretical research and physical experiment has become three main methods to find new knowledge and discovery. It may partly take the place of animal and human experiment in traditional research of iatrology. In this paper, airflow distribution in nasal cavity was investigated based on three-dimensional reconstruction model to try to find the correlation between the nasal cavity structure and the airflow characters. Knowledge of airflow in human nose is important for understanding many aspects of the biology and pathology in the respiratory tract. Through this research, we can more profoundly explore the outbreak, treatment and prevention of nasal diseases.The main work in each chapter of the research is summarized as follows:In chapter one, significance and background for the research of this paper was first introduced. The definition of nasal respiratory mechanics and the brief development history, research contents, research methods were presented. At last, advance of domestic and foreign research in this field was summarized in details.In chapter two to chapter five, several three-dimensional, anatomically accurate representations of adult human nasal cavity models were reconstructed based on computed tomography medical images. The Navier-Stokes and continuity equations for airflow were solved using the finite element method under linear-state, respiratory conditions simulating rest and light exercise with the fluid dynamics software package ANSYS. Airflow distribution character was generalize and contrasted to each other. As a basis, anatomy of nasal cavity, numeralization of medical CT images and three-dimensional reconstruction theory were introduced at the front. The accuracy of reconstructed model in geometry structure was proved by acoustic rhinometry test, since it can quantify upper airway condition by drawing a graph plotting the distance from the nostril vs. the cross-sectional area witch is correspond to the typical anatomic structures of human nasal cavity. At last, the model was abstracted to the combination of characteristic structure. After the statistic of characteristic dimension for nasal structure, method to build standard nasal cavity model, which could represent the ones with similar structure, was put forward.In chapter six, on the basis of animal experiment, living bone tissue stress and remodeling adaptation biomechanical model was set up. The numerical representation of the course was obtained. The technique route was useful for the quantitative mutual relationship between configuration and function in the nasal cavity.In chapter seven, the whole thesis was summed up. As while, the expected research direction and further work in the future was presented.The research work in this paper is supported by National Natural Science foundation of China (fund number: 10472025; 10672036) and Natural Science Foundation of Liaoning Province, China (fund number: 20032109).
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