毕业设计外文翻译资料
散热器的结构原理及优化方法的
设定
1 绪论
1.1选题的背景及意义
随着汽车发动机转速和功率的不断提高,热负荷也愈来愈大,对冷却系统的要求也越来越高,人们对包括散热器在内的冷却系统的研究愈加重视,新技术、新材料不断涌现。汽车铝散热器产品的优势体现在轻量化、可靠性高、价格低以及生产环保,整车厂采用铝水箱替代原有铜水箱是汽车散热器技术发展的必然趋势。目前,汽车散热器正朝着轻型、高效、经济的方向发展,国内乘用车产品90%以上采用的是铝散热器,在商用车上的使用近年也陆续采用并有扩大的趋势。
因此如何提高散热器的传热效能是一个综合性的经济效益问题,应通过技术经济比较后确定。在提高散热器的散热效率的情况下同时考虑降低散热器的散热阻力,合理选择使用板片材质和橡胶密封垫材质,使用正确的安装方法,才可保证设备安全运行,延长设备的使用寿命。通过计算机的模拟,可以使管带式热器性能更为优越,结构更加合理,经济性更强。另一方面,现代计算机技的快速发展和进步也为管带式散热器的优化设计提供了强大的技术支持,所以管带式散热器的优化设计对于现代诸多工业的可持续发展有着深远的意义。
1 Introduction
1.1 Background and Significance topics
Power continues to increase, more and more large heat load on the cooling
system requirements are also increasing , people including the radiator cooling system pay more attention to research , new technologies , new materials emerging. The advantages of automotive aluminum radiator products is reflected in the lightweight , high reliability , low prices and the production of environmentally friendly vehicle plant to replace the original copper- aluminum radiator auto radiator tank is the inevitable trend of technological development . Currently, the auto radiator is moving light , efficient and economic direction, more than 90% of domestic passenger car is aluminum radiator, in recent years, the use of commercial vehicles have gradually adopted and is growing .
Therefore, how to improve the heat transfer performance of the heat sink is a comprehensive economic issues , through technical and economic comparison OK. Improve the efficiency of the heat sink in the case of taking lower radiator cooling resistance , a reasonable choice to use Plate material and rubber gasket material, using the correct installation method can ensure the safe operation of equipment , extend equipment life . Through computer simulation, you can heat the pipe band performance is more superior, more rational structure , economy stronger .On the other hand , the rapid development of modern computer technology and progress but also for the optimization of the radiator pipe belt design provides a strong technical support, so pipe radiator with the optimal design for the modern sustainable industrial development has a number of far-reaching significance .
1.2车用散热器的分类
能满足某种规定工艺的要求使得热量从热流体到冷流体传递的装置被称为换热器。换热器的分类方法有很多,最基本的是按照工作原理来分:通常可分为回热式、混合式和间壁式三大类。回热式换热器多用于空气预热。一般是将金属和砖类物体做成流道,热流体和冷流体交替地流过同一个通道,并尽量避免混合。在混合式换热器中全部流体均匀地处于同温同压下离开换热器。这种换热器虽然换热效率高,但因两种流体的相互混合,故其在应用上受到一定的限制。间壁式换热器中,高温流体和低温流体由壁面间隔分别位于壁面的两侧,热量通过壁面进行传递。
1.2 Classification of car radiator
To meet the requirements of a process that provides the heat from the hot fluid to the cold fluid transfer device is called the heat exchanger. Classification of heat exchangers there are many ways , the most basic working principle is based on points : usually divided into a heat recovery , hybrid and partitioned three categories. Recuperative heat exchanger used for air preheating . Generally is made of metal and brick -like object flow channel , alternately hot and cold fluids flow through the same channel , and try to avoid mixing .In a hybrid heat exchanger fluid evenly in all the same temperature and pressure leaving the heat exchanger . While this heat exchanger efficiency is high, but the two fluids are mixed , so its application subject to certain restrictions . Recuperative heat exchanger , the high temperature fluid and the low temperature fluid between the wall surfaces are located on both sides of the wall , the heat transfer through the wall surface .
1.3 车用散热器的性能评价
在符合各方面工况要求的前提下,人们仍然需要平衡散热器技术上的先进性和经济上的合理性,即所谓的散热器性能评价问题,以便更好地确定和比较散热器的完善程度。广义地说,散热器的性能含义很广,有阻力性能、传热性能、经济性、机械性能等。用一个或多个指标从一个方面或几个方面来评价换热器的性能问题一直是专家长期以来所探索的问题,目前尚在研究改进中。
1.3 Performance evaluation of car radiator
All aspects of working conditions in line with requirements under the premise that people still need to balance the radiator technically advanced and economically reasonable, the so-called heat sink performance evaluation in order to better determine and compare the degree of perfection of the radiator . Broadly speaking , the performance implications of the radiator is very broad, there is resistance properties, heat transfer performance , economy and mechanical properties. With one or more
indicators from one aspect or aspects to evaluate the performance of the heat exchanger has been the expert 's long exploration of the problem , which is still under study improvements .
1.4 汽车散热器概述
汽车散热器属于间壁式换热器,其中散热水管一般为椭圆管或扁管,外侧布置有多层翅片以强化与冷空气侧的传热。通常,汽车散热器由主片、芯体、封条等零件通过钎焊工艺焊接而成,它的结构紧凑、轻巧、薄壁及传热强度高。根据芯体中翅片排列方式分,汽车散热器主要分为管带式和管片式两种.
1.4 Overview of Auto Radiator
Auto Radiator belong recuperative heat exchanger , where heat pipes is generally oval tube or flat tubes, finned outer layers are arranged in order to strengthen the cold side of the heat transfer . Typically , car radiator from the main piece , core body, seals and other parts welded together by brazing process , it is compact, lightweight , thin-walled and heat transfer and high strength. According to the core body fin arrangement points, automotive radiator divided into tube and tube sheet with two kinds ,
2汽车散热器结构设计
2.1 散热管
咬口焊接制造水管是在联合制管机上能够以7~10个工序滚压成型,通过7~10组特殊的导板和滚轮逐渐的弯曲成型,在成型的最后过程中,带料差不多卷成圆形时,再继续前行,带料将碰到一个圆定不动的扁型断面芯板,芯板断面的形状、尺寸和欲制造的管子内部形状相同,然后连续的进行焊接,进入钎焊炉,将咬口部位和外表面同时镀锡,冷却后,用几组校直滚轮矫正端面形状,扭曲度等,然后按所需的长度自动切断。联合制管机一般24~26m/s。
2. 2散热带
散热带上开有扰动气流的类似百叶窗的孔,以破坏流动空气在散热带表面上
的附着层,提高散热能力。由波纹状散热带和冷却管相间排列经焊接而成所组成的散热器为管带式散热器。
2 car radiator design
2.1 heat pipe
Manufacture of pipes welded seams in the United pipe machine capable of 7 to 10 roll forming process by 7 to 10 special set of guides and rollers gradually bending in the final molding process, almost rolled into a circular strip , and then move on a circle with a given material will encounter immovable flat -section core , core cross-section shape, size and shape of the inside of the pipe for manufacturing the same , and a continuous welding , brazing furnace into , the seams at the same time parts of tin and an outer surface , after cooling , straightening rollers with several groups face shape correction , distortion degree , and then cut off the desired length . Joint pipe machine generally 24 ~ 26m / s.
2.2 Thermal Tape
Cooling air disturbance opened to bring the louver -like holes to destroy the flowing air to the heat adhesive layer on the belt surface , to improve heat dissipation . By the corrugated fins and cooling with alternating warp composed of welded pipe radiator with radiator .
2.3主片及上下水室
散热器的主片及水室的构造均以工艺简便,节约材料,易于钎焊和装配,牢固可靠为前提。
主片中的水管孔的排列要完全符合散热片中水管的排列和数量,散热器上水室一般高60~100mm,容积应该与水关的总容积想适应,并且要稍大于水管的总容量,同时还要考虑发动机水套的容量和进水管的尺寸,另外还要便于安装其他的附件,如进水管,加水口,内部隔板等。
2.3 main piece upper and lower water chamber
The main piece and radiator water chamber structure are simple process , saving material , brazing and easy to assemble, solid and reliable as a precondition.
The film's main water pipe holes are arranged to be in full compliance with heatsink arrangement and number of pipes , radiators Sheung Shui chamber generally high 60 ~ 100mm, the volume should be related to the total volume of water would adapt to , and slightly larger than the total capacity of water , but also consider the capacity of the engine water jacket and the inlet pipe size , while also easy to install other accessories such as inlet pipe, plus intakes, internal partitions, etc. .
2.4 左右侧板及装机架
散热器的固定框架是将散热器固定在汽车上必须的部件,包括左右侧板,U型件,三角吊耳等。用来保证芯部刚度,并在起撒谎能够安装有关零件。左右侧板是直接焊接在水室上的,底部托住下水室,并一起外沿焊接在上下水室上,U型件和三角吊耳是用来安装和固定散热器总成。
2.4 left and right plates and installation frame
Radiator radiator fixed frame is to be fixed in the car components, including left and right side panels , U-shaped , triangle hanging ears and so on. Used to ensure that the core stiffness , and in the relevant parts can be installed from the lie . Left side is soldered directly to the water chamber on the bottom hold the water chamber and the outer edge welded together on the upper and lower water chamber , U-shaped pieces and triangular lug is used to install and secure the heat sink assembly.
2.5散热水管
大多数情况下,散热器的进出水管是由生铁铸造成的并以铆钉,加强板和钎焊固定在水室上,为了增加强度,在很多散热器的结构上,水管是穿过水室的,并在它相对的两壁上加焊。散热器的进出水管通常是焊接在水室上的。散热器的上部加水口平时常用盖严密封住的,以防冷却水溅出。但如果冷却水中水蒸汽过多,将使冷却系内压力过大,可能导致散热器破裂。因此,必须在加水口处设置排除水蒸气的通道-泄气软管。
2.5 Cooling water
In most cases, the radiator inlet and outlet pipe is caused by the Health and cast-iron rivets, reinforcing plate and brazing fixed on the water chamber , in order to increase the strength of the structure in many radiator , plumbing is through the water chamber and in its two opposite walls plus welding . Radiator inlet and outlet pipe is usually soldered on the water chamber . The upper part of the radiator filler neck usually used cap tightly sealed to prevent the cooling water spill. However, if too much water vapor in the cooling water , cooling the pressure will be too large, may result in rupture of the radiator . Therefore, you must add water vapor at the outlet of the channel set exclusion - discouraged hoses.
3 管带式散热管传热过程的理论分析
散热管的传热过程的分析,主要主要进行的分析计算如下,包括管带式散热管的传热计算;散热面积的计算;当量直径的计算;对数平均温差△t m;传热系数K;水侧换热系数hi
3 cooling tube with theoretical analysis of heat transfer process Heat pipe heat transfer analysis of the process , mainly for the analysis of the main calculated as follows , including the tube -type heat pipe with heat transfer calculation ; cooling area calculations ; equivalent diameter is calculated ; logarithmic mean temperature difference △ tm; heat transfer coefficient K; water side heat transfer coefficient hi
4提高散热器散热性能的有效途径
根据传热方程
tmQKFtm式可以看出来,要增加热量Q,无论是增加K,还是F,都能起到一定的效果。工业设计和生产实践中大都从这些方面考虑
强化散热器的传热。所以提高散热器的散热性能的途径有:改善传热系数K;增加对数平均温差;扩大传热面积F;减少散热器重量
4 radiator cooling performance improve effective way
According to the heat transfer equation can be seen to increase the heat ,QKFtm whether it is increased , or , can play a certain effect . Industrial
design and production practice mostly from these considerations strengthen the radiator heat . Therefore, to improve the performance of the heat sink through: improving the heat transfer coefficient K; increase the logarithmic mean temperature difference ; enlarged heat transfer area F; reduce heat sink weight
5 管带数学模型的建立
人们在设计散热器时所追求的目标是:根据冷却系统的要求,在给定空间容积的条件下求得最大的散热量,同时又获得尽量小的压降;或者是在Q和P值一定的前提下,使散热器所消耗的材料最省。因此,这是一个多目标的优化问题。 优化问题的三个条件主要是优化变量的选取,约束条件设定,目标函数的设置。
5 with a mathematical model
People in the design of the radiator when the goal is: According to the requirements of the cooling system in a given volume of space obtained under the conditions of the maximum amount of heat while to get as small pressure drop ; or Q and P values in certain under the premise of the radiator materials consumed most provinces . Therefore, this is a multi-objective optimization problem .The three main criteria optimization problem is to optimize the selection of variables , constraints set , the objective function is set .
6 基于MATLAB优化工具箱实现散热管数学模型的求解 Matlab软件的优点包含:
1、友好的工作平台和编程环境。
2、简单易用的编程语言
3、强大的科学计算数据处理能力
4、出色的图形处理功能
5、应用广泛的模块集合工具箱
优化方法的设定。优化方法是利用MATLAB的优化工具箱,可以求解线性规划、非线性规划和多目标规划问题。具体而言,包括线性、非线性最小化、最大最小化、二次规划、线性与非线性的最小二乘解等问题。另外,该工具箱还提供了线性、非线性最小化,方程求解,曲线拟合,二次规划等问题中大型课题的求解方法,为优化方法在工程中的实际应用提供了更方便、快捷的途径。
优化的散热器属于非线性多变量约束优化问题,在MATLAB中,采用Fmincon优化工具箱中的“Active Set”算法。
计算的结果表明,采用优化设计具有以下有点:
(1)大大节省了设计时间,提高了工作效率;工厂设计一台散热器往往是先凭经验设计,制出样机,然后用试验方法验证样机设计的合理性(若试验结果不理想,再重新修改设计方案)。
(2)散热面积与原方案相比,优化方案可增加1.6%-1.72%。压降特性与原方案相比,优化方案减少6.38%-6.5%。单个散热管的质量相比,优化方案减少
1.52%-1.55%。
6 Based on MATLAB Optimization Toolbox to achieve mathematical models for solving the heat pipe
Matlab software advantages include :
1 , friendly platform and programming environment.
2 , easy to use programming language
3 , a powerful data processing capabilities scientific computing
4 , excellent graphics capabilities
5 , widely used collection of modules Toolbox
Setting optimization method .optimization method is to use MATLAB optimization toolbox, you can solve linear programming, nonlinear programming and multi- objective programming . Specifically, including linear , nonlinear minimize, minimize, maximize , quadratic programming , linear and non-linear least squares solution of other issues. In addition, the toolkit also provides a linear , nonlinear minimization , equation solving , curve fitting , quadratic programming problems in
the method for solving large-scale project for the optimization method in the practical application of engineering to provide a more convenient and efficient pathway .
Optimized non-linear multi-variable radiator constrained optimization problems, in MATLAB , using Fmincon optimization toolbox
Calculation results show that the optimal design has the following advantages: ( 1 ) significant savings in design time , improve work efficiency ; factory to design a heat sink design is often the first rule of thumb , a system prototype, and then with the test method to verify the reasonableness of the prototype design ( if the test results are not satisfactory, and then re- modify the design ) .
( 2 ) cooling area with the original schemes, optimization program to increase
1.6% -1.72% . Pressure drop characteristics compared with the original plan and optimize programs to reduce the 6.38% -6.5 % . Compared to a single heat pipe quality , optimizing programs to reduce the 1.52% -1.55 % .
总结
毕业设计是大学学习中最重要的一门科目,它要求我们把大学里学到的所有知识系统的联系起来,进行理论联系实际的总体考虑。同时也培养了自学与创新能力。因此本次设计综合性和实践性强、涉及知识面广。所以在设计中既了解了基本概念、基本理论,又注意了生产实践的需要,将各种理论与生产实践相结合,来完成本次设计。
我选择的车用散热器的优化与设计的课题,主要介绍了汽车散热器的结构特性和功能特性,理论论述了散热器的传热过程和压降特性,提高散热器性能的有效途径和散热器优化方法的选择。在计算机中建立数学模型的方法来研究散热器的特性,将会对散热器的性能测试、结构优化、产品选型以及新产品的开发等起到指导或辅助作用,从而可避免常规试验分析方法周期长和费用高的问题。
运用工程软件MATLAB优化工具箱,不仅算法可靠,而且无需大量的编程程序,大大减少了计算工作量,提高了工作效率,是一种行之有效的工作方法。可以既提高了工作效率,又避免了资源浪费。
Summary
University graduation design is the most important one subject , which requires us to all the knowledge learned in university systems linking theory with practice for general considerations . But also cultivate self-learning and innovation. Therefore, this design comprehensive and practical and involves extensive knowledge . Therefore, in the design of both the understanding of the basic concepts and theories , but also pay attention to the needs of the production practice , the various theories and production practice, to complete this design .
I chose the car radiator optimization and design issues , mainly on the structural characteristics of automobile radiators and functional characteristics , the theory discusses the radiator heat transfer and pressure drop characteristics of an effective way to improve the performance of the radiator and cooling optimization method of choice . A mathematical model in the computer methods to study the characteristics of the radiator , the radiator will be on performance testing , structural optimization , product selection and development of new products play a guiding or supporting role, thereby avoiding routine test methods cycle length, and cost is high.
The use of engineering software MATLAB optimization toolbox , not only algorithms and reliable, and without a lot of programming procedures , greatly reducing the computational workload, improve work efficiency, is an effective way of working. Can only improve the work efficiency, but also to avoid the waste of resources .
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