人体理想口喉模型内非稳态呼吸流场及温、湿度场的数值模拟

论文总字数：26587字

摘 要

近年来，可吸入颗粒物对人们的身体健康造成的危害引起了广泛的关注，越来越多的研究人员对此展开研究，吸湿性颗粒物的相关研究就是其中之一。吸湿性颗粒物的吸湿增长易受环境温度和湿度的影响，因此只有准确地模拟呼吸道内的温度、湿度条件，才能预测吸湿性可吸入颗粒物在人体气道内的运动和沉积。本次研究的目的是针对含有周边人体组织的理想口喉模型，开展非稳态呼吸的数值模拟，在人体组织温度变化趋于稳定后分析呼吸道内流场和温、湿度场随时间的变化。

本文构建了含有空气流道、黏液层和周边组织的理想口喉模型，其中空气流道为流体域，黏液层与周边组织简化为固体域，经网格独立性校验后总网格数为289.3万。其中流体域内进行非稳态呼吸下湿空气流动与非定常边界温度下水分蒸发模拟，固体域进行导热和黏液层内因蒸发而丧失汽化潜热的计算。本文实现了非稳态呼吸和边界传热条件下人体口喉模型内流动、边界对流换热、汽化潜热和导热的预测。通过多个呼吸周期的计算，使呼吸道黏液-组织区域内温度在呼吸周期内随时间变化波形稳定，给出了呼吸周期内不同时间点的速度、温度和相对温度分布。

主要结论为：呼吸循环在第3个周期之后基本已经达到稳定状态；吸气时与呼气时，口喉模型内平均温度相差约6°C，相对湿度相差约60%；在口喉模型弯管处，温度波形在多个呼吸循环后达到稳定状态，与第一个呼吸波形相比温度下降可达1.3°C。

关键词：非稳态呼吸；理想口喉模型；湿空气；温湿度分布

Abstract

In recent years, the harm of inhalable particle on people's health has attracted wide attention, more and more researchers started to study them, the study of hygroscopic particle is one of them. The hygroscopic growth of hygroscopic particle is susceptible to ambient temperature and humidity, so the movement and deposition of hygroscopic inhalable particle in human airway can only be predicted by accurately simulating the temperature and humidity conditions in the airway. The aim of this study is to simulate the non-steady respiration in a simple mouth-throat model with the human tissue, and to analyze the change of the flow field and the temperature and humidity field in the airway after the temperature change of the human body tends to be stable.

In this paper, the ideal mouth-throat model with air flow channel, mucous layer and surrounding tissue is constructed. The air flow channel is the fluid domain, while the mucous layer and its surrounding tissue are simplified as the solid domain. After the mesh independency test, the mesh number in total is 289.3 million. In the fluid domain, the wet air flow under unsteady respiration and the evaporation of water at unsteady boundary temperature are simulated. In the solid domain, the heat conduction and the latent heat loss in the mucous layer due to evaporation are calculated. The prediction of flow, boundary convective heat transfer, latent heat of vaporization and thermal conductivity in the human mouth-throat model under unsteady breathing and boundary heat transfer are realized. The velocity, temperature and relative temperature distribution at different time intervals in the respiratory cycle are analyzed when the temperature of the airway mucous - tissue region reaches an equilibrium status with the time of the respiratory cycle.

The main conclusions are: the respiratory cycle has basically reached a steady state after three breathing cycles; the average temperature difference of the inspiration and expiration is approximately 6°C in the mouth-throat model, and the relative humidity difference of the inspiration and expiration is about 60%. In the curved pipe region of the mouth-throat model, the value of the temperature waveform can decrease by 1.3°C when it reaches an equilibrium status after multiple breathing cycles comparing to the first cycle.

Key words: Transient breathing; Idealized mouth-throat airway model; Wet air; Temperature and humidity distributions

目 录

摘 要 I

Abstract II

目录 III

第一章 绪论 1

1.1研究背景及意义 1

1.2国内外研究进展 2

1.3研究思路和技术路线 3

1.4本章小结 4

第二章 控制方程 5

2.1 Transition SST湍流模型相关方程 5

2.2干空气和水蒸气相关方程 7

2.3黏液层和组织层的控制方程 8

2.4本章小结 8

第三章 模拟对象与条件 9

3.1理想口喉模型 9

3.2边界与初始条件 9

3.3 Fluent软件相关设置 10

3.4本章小结 11

第四章 结果分析 12

4.1流场分布 12

4.1.1 第1个呼吸循环的流场分布 12

4.1.2 第2个呼吸循环的流场分布 14

4.1.3 第10个呼吸循环的流场分布 15

4.2温度场分布 17

4.3湿度场分布 18

4.4温度与速度变化 20

4.4.1 口喉模型进出口速度变化 20

4.4.2 口喉模型进出口质量流量变化 21

4.4.3 口喉模型进出口附近截面流体区域和固体区域的温度变化 21

4.4.4 口喉模型进出口附近单元点的温度变化 22

4.5与稳态条件下吸气过程的一些对比 24

4.6本章小结 25

第五章 结论与展望 26

致 谢 27

参考文献： 28

第一章 绪论

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