【作者】 周洋；

【导师】 邓文君； 昌建林；

【作者基本信息】 华南理工大学 ， 机械工程（专业学位）， 2019， 硕士

【摘要】 进入21世纪后,得益于化石能源的广泛开采和使用,人类社会得到了快速的发展和进步。但是,化石能源的大量开采的同时也引发了能源短缺和环境污染等问题。翅片技术是一种能够极大地提高能源利用率的节能技术,被广泛应用于石油化工、余热回收、空调制冷、核能、航天航空、电子冷却系统等各行各业中。本文提出了一种新方法来加工三维翅片——滚压-切削成形法,通过实验和有限元模拟探究了该方法可行性。主要研究内容如下:(1)设计了滚压-切削组合刀具,分析了该工艺的成形过程,该工艺由滚压工艺和切削工艺组成,在滚压工艺中,带槽辊滚压工件的过渡表面,形成微沟槽结构;在切削工艺中,带有薄底的微沟槽结构被切削刀具切除下来,此时在切削变形的作用下,微沟槽结构会得到膨胀、放大,最终形成具有丰富表面形貌的三维翅片。(2)使用DEFORM-3D建立了该工艺的有限元模型,分析了各加工参数对该工艺的等效应力、等效应变率、切削温度、主切削力的影响。(3)详细分析了该工艺的成形原理。该翅片主要由主结构、复合结构和微观结构等丰富表面结构组成,该翅片的主结构呈倒置的抛物线形;复合结构呈周期性分布于翅片的顶部,由大量的非规则矩形突起组成;微观结构主要分布于翅片的底部,由大量的线状结构组成。(4)探究了各加工参数对翅片尺寸、硬度和腐蚀性能的影响。实验结果表明:随着刀具前角的减小、滚压深度的增加、进给量的增大以及切削深度的减小,翅片高度越来越高。翅片的硬度值是明显高于基体材料的硬度值的,说明加工过程中产生了剧烈的加工硬化现象。该翅片的电化学实验结果表明:该翅片在0.5 mol/L的HCl溶液中的与在0.5 mol/L的NaCl溶液中的奈奎斯特曲线相似,该翅片在这两种溶液中的耐腐蚀性能差别不大,并且刀具前角越小,翅片的耐腐蚀性能越强。更多还原

【Abstract】 After entering the 21 st century,thanks to the extensive exploitation and use of fossil energy,human society has made rapid development and progress.However,the massive exploitation of fossil energy has also caused lots of problems such as energy shortages and environmental pollution.Fin technology is an energy-saving technology that can greatly improve energy efficiency.It is widely used in petrochemical industry,waste heat recovery,air conditioning and refrigeration,nuclear energy,aerospace,electronic cooling systems and other industries.In this paper,a new method is proposed to produce 3-D fins,namely rolling-cutting forming method.The feasibility of the method is investigated by experiments and simulations.This paper mainly includes the following aspects:(1)The rolling-cutting combined tool is designed and the forming process of the process is analyzed.The process consists of rolling process and cutting process.In the rolling process,the grooved roller rolls the transition surface of the workpiece to form a micro-groove structures.In the cutting process,the micro grooved structures with a thin bottom are cut from the workpiece by the cutting tool.At the same time,under the action of cutting deformation,the micro grooved structures are swollen and magnified.And finally the 3-D fins with abundant surface structures are formed.(2)The finite element model of the process is established using DEFORM-3D.The effects of various processing parameters on the effective stress,effective strain rate,cutting temperature and main cutting force of the processs are analyzed.(3)The forming mechanism of the process is analyzed in detail.The fin is mainly composed of the primary structure,the composite structures and the micro structures.The primary structure is inverted parabolic.The composite structures are periodically distributed on the top of the fins,which is composed of a large number of irregular rectangular protrusions.The micro structures are mainly distributed at the bottom of the fins and consists of a large number of linear structures.(4)The influences of various processing parameters on the fins size,hardness and corrosion performance are investigated.The experimental results show that as the tool rake angle decreases,the roll depth increases,the feed rate increases,and the depth of cut decreases,the fins height becomes higher and higher.The hardness of the fins is significantly higher than the hardness of the base material,indicating that the work hardening phenomenon occurs during the processing.The electrochemical experiment results of the fins show that the Nyquist plot of the fins in the 0.5 mol/L HCl solution are similar to the Nyquist plot in a 0.5 mol/L NaCl solution.The fins have little difference in corrosion resistance between the two solutions.And the smaller the rake angle,the stronger the corrosion resistance of the fins.更多还原