RESEARCH OF LAMINAR BOUNDARY LAYER INFLUENCE OF THE AIR FLOW ON THE MUCOUS MEMBRANE OF THE NASAL CAVITY

The purpose of the work is to develop a theoretical basis for determining the thickness of the laminar boundary layer in the nasal cavity during respiration. Methods for obtaining basic scientific and practical results are based on the general principles of theoretical physics and aerodynamics in order to determine the laminar boundary layer of air flow in the upper respiratory tract. Using the aerodynamic approach to the study of respiratory and olfactory disorders revealed that the thickness of the laminar boundary layer decreases with decreasing equivalent diameter of the nasal cavity and with increasing Reynolds number, which characterizes the degree of turbulence in the air flow. Typical values of the thickness of the laminar boundary layer are in the range of 0.2-0.05 mm, depending on the mode of nasal breathing and the configuration of the nasal cavity. The data obtained characterizes the effect of airflow on the mucous membrane of the nasal cavity: if the heterogeneity of the mucosal surface extends beyond the boundary of the laminar boundary layer, then such portions of the nasal cavity are exposed to turbulent flow, which leads to overdrying. The size of the heterogeneities of the mucosa is determined by tomographic data during their processing at the sub-pixel level, which allows for the investigation of the effect of the intensity of the boundary elements of the walls of the nasal passages. A model of the distribution of airflow velocities in the nasal cavity in the turbulent mode is proposed; it has a logarithmic or power profile cross section, and within the laminar boundary layer the air velocity increases linearly to almost the max value. The current air velocity in the cross sections amounted to 5-7 m/s. The feature of the developed method is transitioned to hydraulic diameter, which takes into account complex configuration of the nasal cavity, as well as an anatomically narrow area - the olfactory slit.