Studies of the human breathing

The article presents four branches of multi-year research of human breathing. They are (1) modeling and study the movement of the convective flows in the artificial models of nose; (2) numerical modeling of the convective flows movement on the computer models; (3) breathing research with the help of diagnostic equipment; (4) determination of the exhaled air composition. In all our studies the breathing was examined as a dynamical process. The results of pressure, temperature, velocity and concentration CO2 measuring in the nostrils and in the significant parts of the artificial model of nasal cavity are presented. For this measurements estimated the correlation entropy, correlation dimension. The 3D geometrical model of human nasal cavities obtained from computer-aided tomography data using Mercury Amira program is also given. The 3D unstructured mesh with 1,5×107 finite elements was constructed after the segmentation using Altair Hypermesh software had been finished. The mesh was used to set up an unsteady simulation of airflow inside the obtained geometrical model. Application of DES method on the mesh of a good quality made it possible to distinguish the small-scale turbulent swirls inside the flow. A gas sensor based on spontaneous Raman scattering is proposed for the compositional analysis of single breath events. The Raman sensor is able to detect all the major gas components, i.e. N2, O2, CO2, and H2O at ambient pressure with a high temporal resolution. Concentration fluctuations within a single breath event could be resolved.

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