连续型螺旋折流板成形数值模拟研究

发布时间：2018-08-27 17:15

【摘要】：连续型螺旋折流板换热器具有优良的传热性能,它的传热效率比弓形折流板换热器和非连续型螺旋折流板换热器更高,而且流体流动阻力较小。但是连续型螺旋折流板制造难度较大,目前多采用模具冲压成形技术制造,但是这种制造方法存在许多不足,例如模具制造困难,通用性差,成本较高,生产周期长。因此,连续型螺旋折流板需要一种更加完善的制造方法。本文提出采用多点成形的方法制造连续型螺旋折流板。多点成形是一种目标形状可调的柔性加工方法,这种方法已经成功的应用于船外板,列车流线型车头覆盖件等复杂形状零件的成形制造,并且取得了很多成功的经验。因此,本文根据连续型螺旋折流板的形状特点,提出用多点成形的方法制造连续型螺旋折流板。本文应用商业软件ANSYS/LS-DYNA对连续型螺旋折流板的成形过程进行有限元数值模拟。通过模拟研究了连续型螺旋折流板多点成形过程中的应力、应变分布及回弹特点。模拟结果表明,螺旋折流板成形后的厚向应变沿螺旋折流板的径向方向由内侧向外侧呈减小趋势;回弹量随着连续型螺旋折流板厚度的增加而逐渐减小。本文以螺旋折流板的厚度、材质以及螺旋折流板的螺距、折流板径向尺寸、基本体大小等为变量,通过对螺旋折流板成形过程的数值模拟,研究这些因素对成形过程中压痕、起皱等缺陷的影响规律。研究结果表明,螺旋折流板成形时起皱、压痕等缺陷随板料厚度的增加而减小;随螺旋折流板螺距的增大而增加。压痕缺陷随板料内径的增大而减少;另外,压痕缺陷随螺旋折流板外径的增大而减少。同时随着基本体尺寸的减小,螺旋折流板的压痕和起皱缺陷减少。连续型螺旋折流板多点成形过程的研究表明,压痕、起皱等成形缺陷可以完全压制在允许范围内,不会对连续型螺旋折流板的使用产生不良影响。因此,采用多点成形方法制造合格的连续型螺旋折流板是完全可行的。
[Abstract]:The continuous spiral baffle heat exchanger has excellent heat transfer performance, its heat transfer efficiency is higher than that of the bow baffle heat exchanger and the discontinuous spiral baffle heat exchanger, and the fluid flow resistance is smaller. However, it is difficult to manufacture continuous helical baffle plate. At present, most of them are made by stamping forming technology. However, there are many shortcomings in this manufacturing method, such as difficult manufacturing, poor generality, high cost and long production cycle. Therefore, continuous spiral baffle plate needs a more perfect manufacturing method. In this paper, a multi-point forming method is proposed to fabricate continuous helical baffles. Multi-point forming is a flexible machining method with adjustable target shape. This method has been successfully applied to the forming and manufacturing of complex shape parts such as outboard train streamlined front panels and so on and many successful experiences have been obtained. Therefore, according to the shape characteristics of continuous helical baffles, a multi-point forming method is proposed to fabricate continuous spiral baffles. In this paper, the forming process of continuous helical baffle plate is simulated by finite element method with commercial software ANSYS/LS-DYNA. The stress, strain distribution and springback characteristics of continuous helical baffle plate in multipoint forming are studied by simulation. The simulation results show that the thickness strain of the spiral baffle decreases along the radial direction of the spiral baffle from the inside to the outside, and the springback decreases with the increase of the thickness of the continuous spiral baffle. In this paper, the thickness, material and pitch of helical baffle plate, radial dimension of baffle plate and basic body size are taken as variables. Through numerical simulation of forming process of helical baffle plate, the indentation of these factors in forming process is studied. The rule of influence of defects such as wrinkling. The results show that the wrinkling and indentation of spiral baffles decrease with the increase of sheet thickness and increase with the increase of pitch of spiral baffles. The indentation defect decreases with the increase of the inner diameter of the sheet metal, and the indentation defect decreases with the increase of the outer diameter of the spiral baffle plate. At the same time, the indentation and wrinkling defects of the spiral baffle are reduced with the decrease of the basic body size. The research on the multi-point forming process of continuous spiral baffle plate shows that the forming defects such as indentation and wrinkle can be completely pressed within the allowable range and the use of continuous spiral baffle plate will not be adversely affected. Therefore, it is feasible to manufacture qualified continuous helical baffles by multi-point forming method.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.5

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