平流层飞艇热特性的数值模拟与分析

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3.0 高德中 2024-11-19 5 4 3.34MB 84 页 15积分
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摘 要
平流层飞艇在对地观测、红外遥感通信等诸多的领域有着十分广阔的应用前
景和非常大的发展潜力，对于平流层飞艇的研究已经成为了当前许多国家研究的
热点问题之一,若要保证其长期运行中的稳定性和易控制等性能，十分有必要对其
进行相应的热特性分析。对于平流层飞艇的热特性这类基础性的研究将会极大的
影响到飞艇的整体设计、飞行控制以及飞行预测的准确度等，是平流层飞艇研究
中亟待攻关的重要技术之一。本课题以平流层飞艇为研究背景，基于Linux操作系
统下的并行计算平台，运用Fluent6.3软件并结合UDF自编程，对平流层飞艇在不同
的复杂的热运行环境的相关热特性进行了数值模拟与分析。
本文首先分析了平流层的辐射以及对流等主要的特性,同时结合气象学和传
热学相关的知识分析了平流层飞艇热环境的复杂形成机制和诸多的影响因素。根
据本文所模拟的对象具有几何尺寸庞大、热边界条件复杂等特点，确立合适的数
值计算方法，并建立了相应的物理模型及网格划分系统，结合UDF自编程，引入
了飞艇外部非均匀的多项辐射和对流组成的复杂热边界条件。通过了网格无关性
验证，同时，进行了数值方法验证，所得的数值计算结果与文献中给出的实验数
据的对比分析，说明了编写的UDF以及选择的数值方法模拟平流层飞艇的热特性
是可行的。
通过数值模拟，首先获得了平流层飞艇的基本换热和流动特性，进而分析太
阳辐射、反照辐射、红外辐射等环境辐射以及对流等因素对平流层飞艇全天各个
时刻囊体表面温度、内部浮升气体温度、囊体内部的流场、气体密度等随时间的
变化规律；其次分析了飞艇运行环境中季节、工作纬度、风速的变化对其囊体内
浮升气体温度昼夜变化产生的影响；然后着重分析了飞艇飞行姿态（俯仰角、偏
航角）的变化以及对飞艇的热控效果有着直接影响的囊体表面材料热物性即囊体
材料的发射率、吸收率以及材料的吸收发射比的不同等因素造成的影响情况，并
重点建立了敷设有太阳能电池的飞艇的废热计算模型，对太阳能电池带来的废热
进行了相应的研究。
本文的数值模拟与分析结果，对于全面了解复杂热环境中的平流层飞艇的相
关热特性提供了必要的知识积累，同时，也为飞艇囊体材料的制备或者选择提供
一定的参考依据，为平流层飞艇的总体设计以及有关热性能方面的分析起到很好
的指导作用。
关键词 平流层飞艇，复杂热环境，材料辐射物性，太阳能电池废热， 数值模拟
ABSTRACT
Stratospheric airship has great application prospects and potential in the fields of
the earth observations，remote sensing , telecommunication services and so on. It has
received more and more attention for its potential applications. To ensure the long term
reliability, stability and control, it is necessary to carry on the thermal analysis. The
basic research of the thermal analysis will affect the airship structure design, flight
prediction and flight control, which is one of the key technologies of the stratospheric
airship study. In this paper, thermal characteristic of the stratospheric airship in different
complex thermal environment conditions are simulated and analyzed by choosing
Computational fluid dynamics software Fluent6.3 as flow solver on the Linux based on
parallel computing system combined with the UDF coding.
First of all, the convective and radiant thermal environment of the stratospheric
airship is analyzed. The heat transfer principle is employed to analyze the complex
mechanism governing the thermal status of the stratospheric airship and the main heat
influencing factors. Numerical simulation methods are chosen according to the
characteristic of the simulated target, which has large size complex thermal boundary
conditions and so on. Furthermore, the relevant physical model and calculation mesh
systems are constructed and the UDF codes are developed to solve the complicated
distribution of uniform temperature and heat flux on the airship surface. TGrid
independence was conducted and numerical method was verified. The comparison
shows that results of numerical simulation are in good agreement with the experimental
data published in literature. It be concluded that the meshing and the numerical
simulation methods with UDF codes of are reasonable.
Numerical simulation results show the heat transfer and flow principle. Based on
the results, the thermal effects on stratospheric airship were analyzed that include sun
radiation, albedo radiation, infrared radiation and others. The characteristics of
temperature of the buoyant gas, speed, density varied with the time and the effects of
the temperature of inside buoyant gas changes with the running environment (season,
operation latitude, wind speed) one day and night are also obtained. According to the
simulation results, the influence of the variations of flight attitude (angle of pitch and
yaw angle) and thermal performance caused by different thermal radiant properties of
envelope materials, such as absorptivity, emissivity and the ratio of absorptivity to
emissivity were studied in detail. Finally, this work stresses on establishing the waste
heat calculation model of the stratospheric airship with solar cells and doing some
research of the waste heat caused by solar cells.
The study in this work can be valuable reference for the further investigation of the
related thermal characteristics of stratospheric airship exposed to complicated thermal
environment. The results are also significantly useful for the envelope material selection,
the precondition of thermal control design and crucial to the development of
stratospheric airship.
Keywords: stratospheric airship, complicated thermal environment,
thermal radiant properties of envelope materials, waste heat of solar
cells, numerical simulation
目 录
中文摘要
ABSTRACT
第一章 绪 论 .......................................................................................................... 1
§1.1 引言 ............................................................................................................... 1
§1.2 平流层飞艇特点及研究意义 ....................................................................... 1
§1.3 平流层飞艇的研究现状、发展水平及前景 ............................................... 2
§1.4 研究对象的主要特征 ................................................................................... 5
§1.5 主要研究内容 ............................................................................................... 6
第二章 基本概念与理论 ....................................................................................... 7
§2.1 平流层飞艇结构组成 ................................................................................... 7
§2.2 飞艇基本受力分析 ....................................................................................... 8
§2.3 平流层飞艇热环境形成机制与特性 ........................................................... 8
§2.3.1 平流层大气热环境 ................................................................................ 9
§2.3.2 平流层飞艇外部热环境 ...................................................................... 10
§2.3.3 平流层飞艇内部热环境 ...................................................................... 10
§2.3.4 平流层飞艇热状况的形成机制 .......................................................... 10
§ 2.3.5 辐射相关的基本概念以及数学模型 .................................................. 11
§ 2.3.6 对流传热相关的基本概念 .................................................................. 17
§ 2.4 本章小结 ..................................................................................................... 18
第三章 数值计算方法 ....................................................................................... 19
§ 3.1 计算传热简述 ............................................................................................. 19
§ 3.2 数值计算方法简介 ..................................................................................... 19
§ 3.3 控制方程 ..................................................................................................... 21
§ 3.3.1 控制方程的建立 .................................................................................. 21
§ 3.3.2 控制方程的离散 .................................................................................. 21
§3.4 对流换热数学模型 ...................................................................................... 23
§3.5 辐射模型 ...................................................................................................... 24
§ 3.5.1 辐射外热流模型 .................................................................................. 24
§3.5.2 内部表面辐射模型的选择 ................................................................... 25
§3.6 湍流的数值模拟方法简介 .......................................................................... 27
§ 3.6.1 直接数值模拟（DNS） ..................................................................... 28
§ 3.6.2 大涡模拟（LES） .............................................................................. 28
§ 3.6.3 Reynolds 平均法（RANS） ................................................................ 28
§ 3.6.4 湍流模型的选择 ................................................................................. 29
§ 3.7 计算域网格划分 ......................................................................................... 30
§ 3.8 用户自定义函数 UDF ................................................................................ 31
§ 3.9 本章小结 ..................................................................................................... 32
第四章 太阳辐射及大气环境影响下平流层飞艇热特性 ................................... 33
§ 4.1 物理模型 ..................................................................................................... 33
§ 4.2 计算网格 ..................................................................................................... 33
§ 4.3 边界条件 ..................................................................................................... 34
§ 4.4 网格无关性验证 ......................................................................................... 35
§ 4.5 计算方法验证 ............................................................................................. 36
§ 4.6 夏至日定点过程模拟 ................................................................................. 39
§ 4.6.1 飞艇囊体表面温度分布 ...................................................................... 39
§ 4.6.2 飞艇囊体内部温度分布 ...................................................................... 43
§ 4.6.3 局部温度沿轴向分布情况 .................................................................. 46
§ 4.6.4 飞艇囊体内部流场分布 ...................................................................... 46
§ 4.6.5 飞艇囊体内部气体密度分布 .............................................................. 48
§ 4.6.6 飞艇内部氦气体积变化估算 ............................................................. 50
§4.7 飞艇热特性的影响因素 .............................................................................. 50
§4.7.1 模型验证 ............................................................................................... 50
§4.7.2 季节的影响 ........................................................................................... 51
§4.7.3 工作纬度的影响 ................................................................................... 52
§4.7.4 风速的影响 ........................................................................................... 53
§ 4.8 本章小结 ..................................................................................................... 54
第五章 飞行姿态、囊体材料、太阳能电池废热对平流飞艇热特性的影响 ... 56
§ 5.1 飞艇姿态的影响 ......................................................................................... 56
§5.1.1 飞艇俯仰角的影响 ............................................................................... 56
§5.1.2 飞艇偏航角的影响 ............................................................................... 57
§ 5.2 材料辐射特性的影响 ................................................................................. 58
§5.2.1 发射率影响 ........................................................................................... 59
§5.2.2 吸收率影响 ........................................................................................... 60
§5.2.3 吸收发射比的影响 ............................................................................... 61
§5.3 太阳能电池废热的影响 ............................................................................. 62
§5.3.1 太阳能电池的热环境 ........................................................................... 63
§5.3.2 物理模型 ............................................................................................... 64
§5.3.3 数值方法 ............................................................................................... 64
§5.3.4 边界条件 ............................................................................................... 65
§5.3.5 计算结果分析 ....................................................................................... 66
§ 5.4 本章小结 ..................................................................................................... 69
第六章 结论与展望 ............................................................................................... 71
§6.1 结论 .............................................................................................................. 71
§6.2 展望 .............................................................................................................. 72
主要符号表 ............................................................................................................. 73
参考文献 ................................................................................................................. 75
摘要：

摘要平流层飞艇在对地观测、红外遥感通信等诸多的领域有着十分广阔的应用前景和非常大的发展潜力，对于平流层飞艇的研究已经成为了当前许多国家研究的热点问题之一,若要保证其长期运行中的稳定性和易控制等性能，十分有必要对其进行相应的热特性分析。对于平流层飞艇的热特性这类基础性的研究将会极大的影响到飞艇的整体设计、飞行控制以及飞行预测的准确度等，是平流层飞艇研究中亟待攻关的重要技术之一。本课题以平流层飞艇为研究背景，基于Linux操作系统下的并行计算平台，运用Fluent6.3软件并结合UDF自编程，对平流层飞艇在不同的复杂的热运行环境的相关热特性进行了数值模拟与分析。本文首先分析了平流层的辐射以及对流等...

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作者：高德中 分类：高等教育资料 价格：15积分 属性：84 页 大小：3.34MB 格式：PDF 时间：2024-11-19

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