CAJ | 학술논문

目的比较周期性呼吸状态与稳态呼吸状态下正常鼻腔气流的流场特点.方法根据正常成人鼻腔的CT扫描,利用计算流体力学软件Fluent建立正常的鼻腔模型,模拟周期性呼吸下鼻腔的气流状况,选取其中某些时刻(呼气加速区第15.600秒、呼气减速区第16.495秒)的气流状态与相同流量下稳态呼气状态下的气流状态进行比较.结果周期性呼吸时第15.600秒与入口流量为697.25ml/s稳态呼气情况下鼻腔气流参数如下:两种呼吸状态下,左鼻腔主要通道气流的平均速度、最大速度和压强相近,各鼻窦内气流的平均速度相近;气流分布均以总鼻道和中鼻道为主,两者分别占气流总流量的50%和30%以上;两种呼吸状态下,下鼻道和总鼻道下部的气流流线均以直线为主,中鼻道、上鼻道和总鼻道中上部的气流流线呈抛物线形.周期性呼吸第16.495秒(距离交界点0.005 s)时鼻腔气流平均速度为0.0706 m/s,气流在鼻咽和鼻阈等宽阔区域形成大范围的涡旋运动;而入口流量为7.62 ml/s稳态呼气时左鼻腔气流的平均速度为0.0415 m/s,鼻腔气体的流动与高流量时相似.结论在相同流量时,除在呼气和吸气交界点附近外,周期性呼吸和稳态呼吸状态下鼻腔气流流动的各参数相似.
목적 비교주기성호흡상태여은태호흡상태하정상비강기류적류장특점.방법 근거정상성인비강적CT소묘,이용계산류체역학연건Fluent건립정상적비강모형,모의주기성호흡하비강적기류상황,선취기중모사시각(호기가속구제15.600초、호기감속구제16.495초)적기류상태여상동류량하은태호기상태하적기류상태진행비교.결과 주기성호흡시제15.600초여입구류량위697.25ml/s은태호기정황하비강기류삼수여하:량충호흡상태하,좌비강주요통도기류적평균속도、최대속도화압강상근,각비두내기류적평균속도상근;기류분포균이총비도화중비도위주,량자분별점기류총류량적50%화30%이상;량충호흡상태하,하비도화총비도하부적기류류선균이직선위주,중비도、상비도화총비도중상부적기류류선정포물선형.주기성호흡제16.495초(거리교계점0.005 s)시비강기류평균속도위0.0706 m/s,기류재비인화비역등관활구역형성대범위적와선운동;이입구류량위7.62 ml/s은태호기시좌비강기류적평균속도위0.0415 m/s,비강기체적류동여고류량시상사.결론 재상동류량시,제재호기화흡기교계점부근외,주기성호흡화은태호흡상태하비강기류류동적각삼수상사.
Objective To compare the characteristics of normal nasal airflow during periodic breathing and steady-state breathing. Methods Fluent software was used to simulate the nasal cavity and paranasal sinus structures following CT scanning of a normal adult subject. Air flow velocity, pressure,distribution and streamlines were calculated and compared during periodic breathing and steady-state breathing. Results The same flux, the performance of nasal airflow on 15. 600 s of periodic breathing and steady-state expiratory( entrance flow was 697. 25 ml/s) were as follows: air flow in the common and middle meatus accounted for more than 50% and 30% of total nasal cavity flow during two respiratory status. Flow velocity and pressure of nasal cavity and each paranasal sinus were extremely similiar. The flow trace during two respiratory status in the inferior and lower part of the common meatus were predominately straight in form. Flow were parabolic in the middle and superior meatus and the middle and upper parts of the common meatus. The flow trace of nasal airflow on 16. 495 s of periodic breathing had wide areas vortex in nasopharynx and limen nasi, the average speed was 0. 0706 m/s, while the entrance flow 7. 62 ml/s stable state of the left nasal expiratory, the average speed was 0.0415 m/s, the flow trace was similar to 697. 25 ml/s. Conclusion The same flow, except in the junction of the respiratory cycle, the performance of normal nasal airflow during periodic breathing and steady-state breathing were similar.