非稳态呼吸时鼻腔空气动力学研究

发布时间：2018-05-29 14:26

本文选题：非稳态呼吸 + 计算流体力学　；参考：《北京协和医学院》2011年硕士论文

【摘要】：背景和目的主要对正常成年男性生理状态下,非稳态呼吸模型中鼻腔气流进行数值模拟研究,并与稳态呼吸层流模型和正弦曲线模拟周期性呼吸模型中的数值进行比较。方法对经过筛选的正常成年男性头部CT进行扫描三维重建,使用Fluent13软件模拟正常人鼻腔、鼻窦结构,以鼻阻力仪测定平静呼吸时流量随时间变化的曲线作为入口边界条件,根据Navier-Stokes方程计算正常鼻腔在非稳态呼吸状态下气流速度、压力、分布、迹线和鼻窦气流交换等参数。并将稳态呼吸及正弦曲线模拟的周期性呼吸状态下计算所得的气场参数进行比较。结果非稳态呼吸状态下,鼻腔最大速度位于鼻瓣区域,气流主要流经中鼻道以及总鼻道中间部分,以层流为主,呼气相和吸气相都有涡旋,吸气相涡旋多于呼气相,速度低时涡旋更明显。吸气相,鼻腔内剪切力最大的部位位于鼻中隔前端。将稳态气流和正弦曲线模拟的周期性变化气流与非稳态情况作对比,对比速度压强的分布、气流状态,剪切力分布趋势,正弦曲线模拟的周期性呼吸状态更接近非稳态呼吸。结论相比于稳态呼吸模型,正弦曲线模拟周期性呼吸是一个更加理想的模型,但是曲线常数的设置有待进一步研究。健康成年男性生理状态下的非稳态呼吸时,鼻腔内气流的空气动力学性质存在一定的共同特性
[Abstract]:Background and purpose A numerical simulation of nasal airflow in the unsteady breathing model of normal adult male was carried out and compared with that in the laminar flow model of steady breathing and the periodic respiration model in sinusoidal simulation. Method The CT scan of normal adult male head was performed by 3D reconstruction. The nasal cavity and sinus structure were simulated by Fluent13 software. The curve of flow rate with time when breathing calmly was measured by nasal resistance instrument as the entry boundary condition. The parameters of airflow velocity, pressure, distribution, trace line and sinusoidal airflow exchange in normal nasal cavity under unsteady breathing state were calculated according to Navier-Stokes equation. The gas field parameters calculated under steady respiration and periodic respiration simulated by sine curve are compared. Result Under the condition of unsteady breathing, the maximum velocity of nasal cavity is located in the region of nasal valve, the airflow mainly flows through the middle nasal tract and the middle part of the total nasal tract, and the laminar flow is dominant, and there is a vortex in both the expiratory and inspiratory phases, and the inspiratory vortex is more than the expiratory one. The vortex is more obvious when the velocity is low. In inspiratory phase, the maximum shear force in nasal cavity is located at the front end of nasal septum. The periodic variation of steady flow and sinusoidal simulation is compared with that of unsteady state. The distribution of velocity pressure, flow state and shear force are compared, and the periodic respiration state simulated by sine curve is more close to unsteady state. Conclusion Compared with the steady-state respiration model, sinusoidal simulation of periodic respiration is a more ideal model, but the setting of curve constant needs further study. The aerodynamics of the nasal airflow in healthy adult men is similar to that of the unsteady breathing in physiological state.
【学位授予单位】：北京协和医学院
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R765

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