平流层飞艇绕流场及其气动性能的数值模拟与分析

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3.0 赵德峰 2024-11-19 4 4 8.21MB 87 页 15积分
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摘 要
平流层飞艇是一种用途及其广泛的现代高空浮空器，是未来国民经济和国防
建设的非常重要高新技术产品。平流层飞艇外部绕流场及其气动性能的计算是保
证飞艇稳定性、运动模拟、能源供应和形状优化等方面研究的前提和基础。随着
计算机科学技术的快速发展，采用 CFD 方法数值模拟平流层飞艇外部绕流场及其
气动性能成为了可能。本文在 CFD 软件 Fluent 6.3 的计算平台上，采用了 Reynolds
时均 N-S 方程、Realizable κ-ε湍流模型和 MRF 技术数值模拟了带螺旋桨和尾翼的
平流层双椭球飞艇绕流场。
本文重点计算在不同来流攻角和来流速度下，厚度比为 1:5 的裸艇体和带尾翼
飞艇的绕流场。通过对比飞艇表面和外部流场的压力、速度、剪应力以及涡结构
等参数的变化来分析螺旋桨和尾翼对飞艇总体气动性能的影响情况。
数值计算结果表明：飞艇背部的流动分离流场是基本对称的，当攻角为 0～10°
时，分离以闭式分离为主；当攻角大于 10°时，分离以开式分离为主；大攻角下会
出现多次分离现象，且分离区随着攻角的增大而增大；10°以上攻角时，尾翼对飞
艇总体气动性能的影响是很明显的，影响程度也均随着来流攻角的增大而增大。
从飞艇的体积阻力看，采用相同面积的 X形尾翼优于十字形尾翼；十字形和 X形
尾翼，并没有很大程度的影响飞艇艇体总体表面摩擦阻力的大小。飞艇外部流场
的局部速度会大于来流速度，特别是在一定攻角下出现了涡流时，较大速度主要
集中在飞艇侧面壁面区、涡流区以及尾流部分区域。
飞艇所受到的气动力系数总体随螺旋桨推力系数的增大而增大，飞艇表面摩
擦阻力的变化量相对于形状阻力的变化量较小；螺旋桨与飞艇尾端的距离对飞艇
气动特性也有很大的影响，该距离越小则影响越大；螺旋桨的抽吸和扰动作用主
要集中在靠近螺旋桨的前方区域，随着螺旋桨推力系数的增大，螺旋桨对其前方
区域的影响范围越广，飞艇尾部壁面压力系数的变化量也越大；螺旋桨的作用并
没有很大程度的改变飞艇周向壁面压力分布规律，而是改变了周向壁面的压力系
数大小。
关键词：平流层飞艇 螺旋桨 尾翼 绕流场 气动性能 数值模拟
ABSTRACT
Stratospheric airship is a modern high-altitude aerostat and is applied widely; it is a
very important high-tech product for our future economic and national defense
construction. The external flow field and aerodynamic performance analysis of the
stratospheric airship is a premise and foundation for ensuring the stability of airship,
motion simulation, energy supply and the optimization of shape for airship. With the
rapid development of the computer science and technology, numerical simulation of
external flow field and aerodynamic performance of the stratospheric airship become
possible. In the present work, numerical simulation has been carried out with Fluent 6.3
using Reynolds-averaged N-S equations, the Realizable κ-ε turbulent model and MRF
technology to analyze the flow field of a stratospheric airship with a propeller and fins.
This work focuses on calculating the external flow field of a 1:5 airship body under
the different angle of attack and velocity. By comparing surface pressure, external flow
field, velocity, shear stress and the vortex structure changes of airship to analyze the
affection of aerodynamic performance for the airship with propeller and the fins.
The results show that the separated flow along with the body axis is basically
symmetric. When the attack angle is 0~10 degree, the separation is closed separation
primarily, and when the angle of attack is more than 10 degree, the separation is open
separation primarily; The high angle of attack will result in multiple separation
phenomenon, and area of separation zones increases with increasing angle of attack;
When angle of attack is beyond 10 degree, the influence of the fins to overall
aerodynamic performance is very clear and influence increases with increasing angle of
attack. For the volume resistance, use the same area X type fins is more superior to
cross-shaped fins. The magnitude of the surface friction resistance is not greatly effected
by the X type and cross-shaped fins. The local velocity of airships external flow field is
greater than the flow velocity especially appeared eddy flow in certain angle of attack.
The larger velocity mainly located in side wall, vortex flow and partial wake area.
The aerodynamic force coefficients increase with increasing thrust coefficients of
the propeller. The variation of friction coefficient on the airship surface is relatively
small comparing that of profile drag coefficient. The distance between the propeller and
the tail of the airship has a great impact on the aerodynamic forces for the airship body.
The smaller the distance is, the greater the effect is. The effects of propeller suction and
disturbance are obvious mainly near the front of the propeller. With the increase of
propeller thrust coefficient, the effective region of propeller is more extensive and the
variation of pressure coefficient is greater. Pressure distribution profile in airship
circumferential surface is not changed a lot, but the magnitude of pressure coefficient
changes obviously with the increasing thrust coefficient.
Key words: stratospheric airship, propeller, fins,
aerodynamic performance, numerical simulation
目 录
中文摘要
ABSTRACT
第一章 绪 论 ...................................................................................................................1
§ 1.1 研究背景和意义 ..............................................................................................1
§ 1.2 平流层飞艇平台的特点 ..................................................................................1
§ 1.3 研究现状和前景 ..............................................................................................2
§ 1.4 本文主要内容 ..................................................................................................5
第二章 平流层飞艇的空气动力特性 .............................................................................6
§ 2.1 飞艇总体受力分析 ..........................................................................................6
§ 2.2 影响飞艇空气动力的因素 ..............................................................................7
§ 2.2.1 飞行姿态和气流方向 ............................................................................7
§ 2.2.2 外部环境和飞行速度 ............................................................................8
§ 2.2.3 飞艇形状和表面情况 ............................................................................9
§ 2.2.4 尾翼类型及其安装位置 ........................................................................9
§ 2.2.5 螺旋桨形状及其推力系数 ..................................................................10
§ 2.3 飞艇的气动力学性能 ....................................................................................11
§ 2.3.1 升力 ......................................................................................................11
§ 2.3.1.1 艇身和尾翼的升力 ....................................................................11
§ 2.3.1.2 艇身和尾翼组合体的升力 ........................................................12
§ 2.3.2 阻力 ......................................................................................................12
§ 2.3.2.1 摩擦阻力 ....................................................................................13
§ 2.3.2.2 压差阻力 ....................................................................................13
§ 2.3.2.3 诱导阻力 ....................................................................................14
§ 2.4 气动参数计算 ................................................................................................15
§ 2.5 本章小结 ........................................................................................................15
第三章 数学模型与数值计算方法 ...............................................................................17
§ 3.1 流体力学模型 ................................................................................................17
§ 3.2 湍流的数值模拟方法 ....................................................................................18
§ 3.2.1 直接数值模拟（DNS）......................................................................19
§ 3.2.2 大涡模拟（LES）.............................................................................. 20
§ 3.2.3 Reynolds 平均法（RNAS）................................................................20
§ 3.2.4 湍流模式的选择 ..................................................................................22
§ 3.2.5 飞艇壁面区流动情况 ..........................................................................22
§ 3.2.6 壁面函数法 ..........................................................................................23
§ 3.3 转动模型的选择 ............................................................................................24
§ 3.3.1 MRF 模型 ............................................................................................. 25
§ 3.3.2 MP 模型 ................................................................................................26
§ 3.3.3 SM 模型 ................................................................................................26
§ 3.4 数值计算方法 ................................................................................................27
§ 3.4.1 控制方程的离散 ..................................................................................27
§ 3.4.2 有限体积法 ..........................................................................................28
§ 3.5 计算网格生成技术 ........................................................................................28
§ 3.6 本章小结 ........................................................................................................30
第四章 带螺旋桨飞艇裸艇体气动性能的数值分析 ...................................................31
§ 4.1 物理模型 ........................................................................................................31
§ 4.2 计算网格 ........................................................................................................31
§ 4.3 边界条件 ........................................................................................................32
§ 4.4 计算方法验证 ................................................................................................33
§ 4.5 裸艇体绕流场的数值模拟 ............................................................................35
§ 4.5.1 体积阻力系数随雷诺数和攻角的变化规律 ......................................35
§ 4.5.2 摩擦阻力和升力系数随雷诺数和攻角的变化规律 ..........................36
§ 4.5.3 飞艇截面周向表面摩擦阻力系数分析 ..............................................38
§ 4.5.4 飞艇截面周向表面压力系数分析 ......................................................41
§ 4.5.5 飞艇外部流场压力和速度分布 ..........................................................43
§ 4.5.6 飞艇轴向截面流场压力和速度分布 ..................................................45
§ 4.5.7 飞艇背部流场分离流线分析 ..............................................................46
§ 4.6 带螺旋桨裸艇体气动性能的数值分析 ........................................................47
§ 4.6.1 形状阻力和摩擦阻力随推力系数的变化规律 ..................................47
§ 4.6.2 升力和俯仰力矩随推力系数的变化规律 ..........................................48
§ 4.6.3 飞艇表面压力系数变化情况分析 .......................................................49
§ 4.6.4 飞艇空间流动结构对比分析 ..............................................................50
§ 4.7 本章小结 ........................................................................................................51
第五章 带尾翼和螺旋桨飞艇气动性能的数值分析 ...................................................53
§ 5.1 尾翼的选择 ....................................................................................................53
§ 5.2 物理模型 ........................................................................................................54
§ 5.3 计算网格 ........................................................................................................55
§ 5.4 边界条件 ........................................................................................................56
§ 5.5 计算方法验证 ................................................................................................56
§ 5.6 带尾翼飞艇气动性能的数分析 ....................................................................59
§ 5.6.1 十字形和 X形尾翼对体积阻力的影响 .............................................59
§ 5.6.2 十字形和 X形尾翼对升力的影响 .....................................................60
§ 5.6.3 十字形和 X形尾翼对摩擦阻力的影响 .............................................61
§ 5.7 飞艇/尾翼表面压力和摩擦阻力分布 ........................................................ 62
§ 5.8 飞艇外部流场截面压力和速度分布 ..........................................................65
§ 5.9 飞艇外部流场截面流线对比 ......................................................................70
§ 5.10 带尾翼飞艇外部流线 ................................................................................71
§ 5.11 螺旋桨对带十字形尾翼飞艇气动性能的影响 ........................................72
§ 5.11.1 螺旋桨对带尾翼飞艇气动力的影响 ..............................................72
§ 5.11.2 飞艇尾部压力分布对比 ..................................................................73
§ 5.11.3 螺旋桨滑流流线 ..............................................................................73
§ 5.12 本章小结 ....................................................................................................74
第六章 结论与展望 .......................................................................................................75
§ 6.1 结论 ................................................................................................................75
§ 6.2 展望 ................................................................................................................76
主要符号表 .....................................................................................................................77
参考文献 .............................................................................................错误！未定义书签。
在读期间公开发表的论文和承担科研项目 .................................................................82
致 谢 ...............................................................................................................................83
摘要：

摘要平流层飞艇是一种用途及其广泛的现代高空浮空器，是未来国民经济和国防建设的非常重要高新技术产品。平流层飞艇外部绕流场及其气动性能的计算是保证飞艇稳定性、运动模拟、能源供应和形状优化等方面研究的前提和基础。随着计算机科学技术的快速发展，采用CFD方法数值模拟平流层飞艇外部绕流场及其气动性能成为了可能。本文在CFD软件Fluent6.3的计算平台上，采用了Reynolds时均N-S方程、Realizableκ-ε湍流模型和MRF技术数值模拟了带螺旋桨和尾翼的平流层双椭球飞艇绕流场。本文重点计算在不同来流攻角和来流速度下，厚度比为1:5的裸艇体和带尾翼飞艇的绕流场。通过对比飞艇表面和外部流场的压力...

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作者：赵德峰 分类：高等教育资料 价格：15积分 属性：87 页 大小：8.21MB 格式：PDF 时间：2024-11-19

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