级间管—翅换热器的机械胀接模拟与实验研究

发布时间：2018-04-28 01:42

本文选题：胀接成形 + 机械胀接　；参考：《上海交通大学》2015年硕士论文

【摘要】：机械胀接是利用模具在管中的推进,使换热管胀大,实现换热管和翅片连接的一种成形工艺。由于其工艺简单,便于大规模自动化生产,管-翅连接强度高等优点,在换热器制造中获得广泛的应用。由于胀接行程的限制,目前机械胀接工艺多用在小型换热器的生产中。机械胀接工艺在大型换热器生产中的应用一直是该领域的难点及热点之一。本文通过有限元仿真和试验的方法,对大型管-翅式换热器的机械胀接工艺进行研究。本文基于弹塑性力学理论,对换热管的胀接过程进行了解析分析,推导了换热管与翅片之间的残余接触压力以及胀接驱动力的解析解。建立了含支撑板结构的大型换热器的机械胀接工艺的有限元模型,并对胀接成形进行仿真计算。分析了胀接驱动力、换热管参数的变化、翅片的倒伏规律以及翅片最易损坏的位置,分析了支撑板的存在对翅片变形的影响,研究了支撑板的弯曲变形情况及原因;通过对对多个换热管胀接的仿真,研究了相邻换热管胀接对中间换热管的影响;研究了模具几何形状对胀接成形的影响,并对胀接工艺进行优化。分别通过解析方法和数值模拟的方法对胀接杆的临界压力进行了计算,并对解析计算公式进行了修正。将计算获得的胀接驱动力与胀接杆的临界压力进行比较,提出胀接生产中可能会出现胀接杆失稳破坏的情况,并提出改进意见。利用换热器试样做了胀接实验,测量了胀接驱动力,以及胀接前后换热管内径、壁厚、管长的变化。实验结果验证了有限元模型的准确性。
[Abstract]:Mechanical expansion joint is a kind of forming technology which can make the heat exchanger tube swell and realize the connection between the heat exchanger tube and the fin by the push of the die in the tube. It has been widely used in heat exchanger manufacturing because of its simple process, convenient for large-scale automatic production and high strength of tube-fin connection. Due to the limitation of expansion stroke, the mechanical expansion process is widely used in the production of small heat exchangers. The application of mechanical expansion process in the production of large heat exchangers has been one of the difficulties and hot spots in this field. In this paper, the mechanical expansion process of large tube-fin heat exchanger is studied by means of finite element simulation and test. Based on the theory of elastoplastic mechanics, the expansion process of heat exchanger pipe is analytically analyzed, and the analytical solutions of the residual contact pressure and the driving force of expansion joint between the heat exchanger tube and the fin are derived. The finite element model of mechanical expansion process for large heat exchangers with supporting plate structure is established, and the simulation of expansion joint forming is carried out. The driving force of expansion joint, the change of heat transfer pipe parameters, the law of fin lodging and the most vulnerable position of fin are analyzed. The influence of the existence of supporting plate on the deformation of fin is analyzed, and the bending deformation and reason of supporting plate are studied. Through the simulation of the expansion joint of several heat transfer pipes, the influence of the expansion joint of the adjacent heat exchanger tube on the intermediate heat transfer tube is studied, and the influence of the die geometry on the forming of the expansion joint is studied, and the expansion process is optimized. The critical pressure of expansion rod is calculated by analytical method and numerical simulation method, and the analytical formula is modified. By comparing the calculated expansion driving force with the critical pressure of the expansion rod, it is pointed out that the instability and failure of the expanded joint rod may occur in the expansion joint production, and some suggestions for improvement are put forward. In this paper, the expansion test of heat exchanger specimen was carried out, the driving force of expansion joint was measured, and the changes of inner diameter, wall thickness and tube length of heat exchanger before and after expansion were measured. The experimental results verify the accuracy of the finite element model.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.5

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