基于CFD的吸尘器内流场分析毕业论文
2021-11-20 22:24:36
论文总字数:18063字
摘 要
随着我国经济持续快速发展,越来越多的消费者开始抛弃传统的人力清洁模式,转而选择使用更为省时省力的吸尘器。各大家电厂商开始投入资金,研究吸尘器的内流场特性,以期提升吸尘器的使用性能。由于计算流体力学与计算机技术的发展,CFD技术作为流场分析的重要方法在此背景下被广泛采用。
本文综合分析了国内外使用CFD方法改进吸尘器结构的案例,并以此为参考进行研究。本文研究对象为一款新型的黑板擦吸尘器,为了使描述更为清晰明了,所以首先介绍了该款吸尘器的结构、主要尺寸参数及其工作原理,并结合文献阐述了相关结构参数对于吸尘器性能的影响。之后利用CFD方法,借助计算流体力学软件AVL fire针对此款吸尘器进行了内流场仿真。在对初始模型的仿真过程中,得到了吸尘器内流场的速度矢量图及压力云图,这两种图分别展现了其内部各个区域的气体运动状态与压力分布情况,通过分析该仿真结果寻找到了最合适的盛灰盒位置与筒体高度。流线的形态直观地展现了流场中气体的运动轨迹,在对比仿真中可以简单清晰地得到各个结构下的吸尘器是否能达到要求。因此之后为了进一步寻找到最合适的旋风粉尘分离器进风口尺寸与位置,便利用分析流线形态的方式分别在三种差异较大的情形下进行了比较。由于影响吸尘器性能的结构参数众多,对任何一部分结构稍加改变便有可能影响其内流场的形态,但以上四种参数的影响最为显著,因此本文所得结果对于提高吸尘器除尘效率具有重要的指导意义。由于AVL fire不支持复杂的建模操作,因此本文首先使用SolidWorks对模型进行几何处理,抽取流体域表面,之后导入AVL fire中设置边界条件完成仿真工作。
研究结果表明:对于此结构的吸尘器而言,盛灰盒应放置于筒体底部、筒体高度在结构允许范围内应取最大值、旋风粉尘分离器进风口尺寸应适中、进风口位置应尽可能设置于最高处。这样改进结构后,可得到较高的除尘效率。
关键词:CFD;吸尘器;内流场仿真;流线;结构优化
Abstract
As China's economy continues to develop rapidly, more and more consumers are starting to abandon the traditional manual cleaning mode and choose to use more time-saving and vacuum cleaners. All electrical manufacturers began to invest funds to study the characteristics of the internal flow field of vacuum cleaners, in order to improve the performance of vacuum cleaners. Because of the development of computational fluid mechanics and computer technology, CFD technology is widely used as an important method of flow field analysis in this context.
This article comprehensively analyzes the case of using CFD method to improve the structure of the vacuum cleaner at home and abroad, and uses this as a reference for research. The research object of this paper is a new type of blackboard cleaner. In order to make the description more clear, the structure, main size parameters and working principles of the vacuum cleaner are first introduced. influences. Then using CFD method, with the help of computational fluid dynamics software AVL fire, this vacuum cleaner was used to simulate the internal flow field. During the simulation of the initial model, the velocity vector diagram and pressure cloud diagram of the flow field in the vacuum cleaner were obtained, which respectively showed the gas movement state and pressure distribution in each region of the vacuum cleaner. The most suitable ash box position and barrel height were found by analyzing the simulation results. The shape of the streamline directly shows the movement path of the gas in the flow field. In the comparison simulation, it can be obtained simply and clearly whether the vacuum cleaner under each structure can meet the requirements. Therefore, in order to further find the most suitable size and location of the cyclone dust separator's air inlet, a comparison was made under three different conditions by means of analyzing the flow pattern. Since there are many structural parameters that affect the performance of vacuum cleaners, it is possible to change any part of the structure slightly to affect the shape of its internal flow field, but the above four parameters have the most significant impact, so the results obtained in this paper have important guiding significance for improving the dust removal efficiency of vacuum cleaners. Since AVL fire does not support complex modeling operations, this paper first USES SolidWorks to perform geometric processing on the model, extract the surface of the fluid domain, and then imports it into AVL fire to set boundary conditions to complete the simulation.
The results show that: for the vacuum cleaner with this structure, the ash box should be placed at the bottom of the barrel, the height of the barrel should be the maximum within the allowable range of the structure, the inlet size of the cyclone dust separator should be moderate, and the inlet position should be set as high as possible. After improving the structure, higher dust removal efficiency can be obtained.
Key Words:CFD;vacuum cleaner;internal flow field simulation;streamline;Structure optimization
目 录
第1章 绪论 1
1.1 研究的背景及意义 1
1.2 文献综述 3
1.2.1 国外研究 3
1.2.2 国内研究 3
1.3 研究目标 4
第2章 吸尘器简介 5
2.1 吸尘器结构与主要尺寸参数 5
2.2 吸尘器工作原理 6
2.3 分离效果的影响因素 7
2.3.1 筒体直径的影响 7
2.3.2 筒体高度的影响 8
2.3.3 进风口的影响 8
第3章 CFD仿真计算 9
3.1 原始模型仿真 9
3.1.1 网格划分 9
3.1.2 边界条件设定 10
3.1.3 仿真结果 10
3.2 旋风粉尘分离器进风口尺寸对比 13
3.3 旋风粉尘分离器进风口位置对比 16
3.4 本章小结 18
第4章 结果分析 19
4.1 盛灰盒位置分析 19
4.2 筒体高度分析 19
4.3 进风口尺寸分析 19
4.4 进风口位置分析 20
第5章 总结与展望 21
5.1 本文内容总结 21
5.2 后续工作展望 21
参考文献 23
致谢 24
第1章 绪论
1.1研究的背景及意义
由于中国GDP以及居民收入的持续快速增长,现在的消费者——特别是居住在大、中规模城市的消费者开始追求更加简便、省力地清扫方式。这就导致了传统的手动灰尘清洁模式不再能满足居民日常生活的需要,于是各式各样的吸尘器开始出现并逐渐发展[1]。为了适应这种新形势的变化,全国许多厂家争相引进国外的先进的吸尘器制造技术与设备,准备争夺更多的市场份额。在这种情况下,可以预见吸尘器市场的竞争将十分激烈[2]。
目前市面上常见的吸尘器类型为真空吸尘器,如图1.1所示可见其结构及相关工作原理,为:真空吸尘器的电动马达快速旋转,空气从吸气口被吸其中,因此灰尘随之进入集尘袋内的过滤器,过滤后的空气再通过排气口的数层过滤片排出[5]。
图1.1 真空吸尘器结构及工作原理
但基于此原理制造出来的吸尘器存在体积大、噪音大、除尘效率较低等缺陷。因此为了改良吸尘器,各国的工程师基于不同的角度提出了各种各样的方法。其中,利用旋风粉尘分离器的工作原理对吸尘器进行改善的方法从结构上解决了绝大部分问题。旋风粉尘分离器是具有简单结构、无可动部、高分离效率、适度压降的一种非常重要的气固分离装置,适合各种工作环境[3]。旋风粉尘分离器(结构及工作原理见图1.2)原先多用于工业生产,但由于将其用于家用吸尘器后可以大幅度提升除尘效率,所以国内外多个厂家开始投入精力研究改进其结构的方法,分析流场对分离效果的影响也在该领域已经成为了重中之重。
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