压力容器非径向接管的应力分析与补强研究
发布时间：2018-12-12 14:56
【摘要】：压力容器是常见的过程装备，由于工艺和结构上的要求，经常需要在压力容器上安装斜向或切向的非径向接管，这种非径向接管需要在容器上开椭圆孔。开孔的结果，，不仅削弱了压力容器器壁的强度，而且在在开孔附近产生严重的应力集中，其峰值应力往往高达容器薄膜应力的数倍。因此，如何正确分析非径向开孔附近的应力集中，采用合适的补强方法，是目前压力容器设计中令人关注的课题。 本文以承受内压作用的压力容器非径向开孔接管为研究对象，用有限元法分别模拟研究了非径向接管的非径向角度、接管厚度、接管内伸长度以及补强圈厚度等四个因素对非径向接管开孔区附近应力分布的影响和应力集中系数。 本文主要工作及所得结论如下： (1)非径向接管的应力集中系数随着非径向角度的增大而显著增大，但并不是单调增大。容器的非径向角度在25—45时，应力集中系数较大。同时通过加圆倒角处理对比分析，发现打磨焊缝对于消除容器开孔的残余应力具有积极的效果。 (2)接管补强的效果较好，但接管与筒体刚度差不应过大，当接管筒体厚度比达到1.2时，补强效果开始降低。本文认为，接管筒体厚度比t T一般取0.8—1.2之间较为合适。 (3)内伸接管的补强效果有限，当补强满足要求时，不必再增加接管的内伸长度，否则会造成弯曲应力的增加。如确需采用接管内伸式补强，建议接管内伸长度控制在h2≤0.5T。 (4)补强圈补强效果仅次于接管补强。但是，由于补强圈使筒体局部壁厚加大，造成局部弯曲应力增大，并且补强圈与筒体之间不能完全贴合，难以与筒体形成一个整体，所以抗疲劳性能差。通过有限元模拟结果可知，补强圈厚度在0.8T至1.2T之间较为合适。补强圈补强结构不宜在高压高温容器上使用。 (5)本文借助空间解析几何坐标变换的理论以及回归分析方法，推导出了半经验半理论的非径向接管应力快速计算公式。通过这两个形式简单的公式，可以比较容易地得到非径向接管的应力分布情况。
[Abstract]:Pressure vessel is a common process equipment. Due to the requirements of process and structure, it is often necessary to install oblique or tangential non-radial nozzle on the pressure vessel, which needs to open elliptical hole in the vessel. The results of opening not only weaken the strength of the wall of the pressure vessel, but also produce serious stress concentration near the hole. The peak stress is often several times higher than that of the membrane stress of the vessel. Therefore, how to correctly analyze the stress concentration near non-radial openings and adopt appropriate reinforcement methods is a subject of concern in the design of pressure vessels at present. In this paper, the non-radial nozzle of pressure vessel subjected to internal pressure is studied, and the non-radial angle and thickness of the non-radial nozzle are simulated by finite element method. The influence of four factors such as the elongation of the nozzle and the thickness of the reinforcing ring on the stress distribution and the stress concentration factor near the opening zone of the non-radial nozzle. The main work and conclusions are as follows: (1) the stress concentration factor of the non-radial nozzle increases significantly with the increase of the non-radial angle, but it is not monotonous. When the non-radial angle of vessel is 25-45, the stress concentration factor is larger. At the same time, it is found that grinding weld has a positive effect on eliminating the residual stress of the open hole of the vessel through the comparative analysis of adding circle chamfering. (2) the effect of nozzle reinforcement is better, but the stiffness difference between nozzle and cylinder should not be too big. When the thickness ratio of nozzle tube reaches 1.2, the reinforcement effect begins to decrease. In this paper, it is considered that the thickness ratio of the tubing tube to t T is generally between 0.8-1.2. (3) the reinforcement effect of the inner extension nozzle is limited. When the reinforcement meets the requirement, it is not necessary to increase the extension length of the nozzle, otherwise, the bending stress will be increased. If it is necessary to adopt the nozzle extension reinforcement, it is suggested that the extension of the pipe should be controlled at H2 鈮
本文编号：2374774
[Abstract]:Pressure vessel is a common process equipment. Due to the requirements of process and structure, it is often necessary to install oblique or tangential non-radial nozzle on the pressure vessel, which needs to open elliptical hole in the vessel. The results of opening not only weaken the strength of the wall of the pressure vessel, but also produce serious stress concentration near the hole. The peak stress is often several times higher than that of the membrane stress of the vessel. Therefore, how to correctly analyze the stress concentration near non-radial openings and adopt appropriate reinforcement methods is a subject of concern in the design of pressure vessels at present. In this paper, the non-radial nozzle of pressure vessel subjected to internal pressure is studied, and the non-radial angle and thickness of the non-radial nozzle are simulated by finite element method. The influence of four factors such as the elongation of the nozzle and the thickness of the reinforcing ring on the stress distribution and the stress concentration factor near the opening zone of the non-radial nozzle. The main work and conclusions are as follows: (1) the stress concentration factor of the non-radial nozzle increases significantly with the increase of the non-radial angle, but it is not monotonous. When the non-radial angle of vessel is 25-45, the stress concentration factor is larger. At the same time, it is found that grinding weld has a positive effect on eliminating the residual stress of the open hole of the vessel through the comparative analysis of adding circle chamfering. (2) the effect of nozzle reinforcement is better, but the stiffness difference between nozzle and cylinder should not be too big. When the thickness ratio of nozzle tube reaches 1.2, the reinforcement effect begins to decrease. In this paper, it is considered that the thickness ratio of the tubing tube to t T is generally between 0.8-1.2. (3) the reinforcement effect of the inner extension nozzle is limited. When the reinforcement meets the requirement, it is not necessary to increase the extension length of the nozzle, otherwise, the bending stress will be increased. If it is necessary to adopt the nozzle extension reinforcement, it is suggested that the extension of the pipe should be controlled at H2 鈮
本文编号：2374774
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