Kinetics Of Nasal Air When Unsteady Breathing

Background and objectiveIn this research we try to investigate the common characteristics of the airflow around healthy male adult volunteers, the differences of airflow parameters between steady respiratory and unsteady respiratory and the comparisons between nasal airflow during sine curve simulated periodic respiratory and measuring periodic respiratory.MethodAn anatomically correct three-dimensional nasal and pharyngeal model was constructed based on computed tomographic scans of a healthy adult male’s nose cavity and paranasal sinus. Fluent software was used to simulate the nasal cavity and paranasal sinus structures. Air flow velocity, pressure, distribution, streamlines and other air exchanging parameters were calculated and compared using Navier-Stokes equation based on the entry conditions that were measured by rhinomanometry under steady-state respiratory and unsteady-state respiratory.ResultsUnder unsteady breathing state, the highest velocity area was at the nasal valve area. The main air flowed through the middle meatus and the middle part of common nasal meatus. The flow mostly was laminar with some vortexes both in expiratory phase and inspiratory phase and there were more vortexes in inspiratory phase or when the flow rate was lower. In inspiratory phase, the regions of maximum shear stress within the nasal cavity were in the anterior part of nasal septum. The distribution of velocity and pressure, airflow state and shear stress distribution trend of steady-state airflow and cyclical changed sinusoidal flow were compared with non-steady state airflow respectively. The sine curves simulated periodic breathing state was closer to the unsteady breathing respiratory state. ConclusionCompared to the steady-state respiration model, sinusoidal simulated periodic breathing is a more ideal model. However, there are still more to be studied about the parameters of the curve of constant. There were common characteristics of the airflow dynamics around the healthy male adult volunteers in physiological non-steady respiratory state.