矩形蒸汽灭菌压力容器的研究

发布时间：2019-01-08 17:51

【摘要】：灭菌锅体是蒸汽灭菌产品内的核心部件之一，它的性能对产品的使用和寿命有着直接的影响。目前蒸汽灭菌容器多采用圆筒形结构，只有在大容积的灭菌容器中才会采用矩形的结构，这种结构一般通过钣金折弯后焊接制造，生产率低。因此，设计一种加工方便、结构新颖可靠的新型矩形压力容器结构对提高灭菌产品的市场竞争力具有积极的意义。本文分别从实验研究、理论分析和数值仿真等三方面对蒸汽灭菌压力容器进行了探讨和研究。采用应变电测法对原有的圆筒形压力容器进行了实验研究，当实验压力为0.35MPa时，可以得到测量点的主应变。根据广义胡克定律，可以将应变值转换为应力值。虽然测量值与理论值有一定的偏差，但是偏差不大，而且两种结果均反映了薄壁圆筒形压力容器和碟形封头的平面应力状态。实验结果还为后面的新型结构设计提供了参考。然后，基于无限长壳体模型，即忽略两端盖的加强作用，采用曲梁力学模型的分析方法对矩形容器进行了受力分析。引入流动半径的概念，发现危险截面产生于最大流动半径处，并推导了受内压作用的壳体计算公式和强度校核条件。根据计算公式和工程经验，对矩形压力容器的壳体、封头、接管和门体进行了详细的设计。其中，容器的容积约为10L，四个侧板之间的圆角为R=30mm，壳体和封头的名义厚度均为4mm，并且壳体和封头采用整体冲压成形。所获得的矩形容器具有结构简单、易于加工、造型大方以及空间利用率高等特点。通过有限元分析软件ABAQUS，对设计的容器进行了结构静力分析。采用结构化网格划分和扫掠网格划分技术进行了网格划分，并根据实际工况加载了边界条件。当加载0.35MPa的均布压力后，容器上最大当量应力出现在圆角处，然后是侧板的中部。圆角处刚好是最大流动半径，可见数值仿真的结果与理论分析一致。结果表明，为了达到与圆筒形容器同等的强度等级，矩形容器的壁厚增加了，但是其空间利用率更高，，因此，在有效容积相等的情况下，矩形容器所消耗的板材更少。综上看来，采用矩形容器并没有显著提高材料消耗。
[Abstract]:Sterilizing pot is one of the core components in steam sterilizing products, and its performance has a direct impact on the use and life of the products. At present, most of the steam sterilizing containers adopt cylindrical structure, only in large volume sterilizing containers will the rectangular structure be adopted. This kind of structure is usually made by welding after sheet metal bending, and the productivity is low. Therefore, the design of a new type of rectangular pressure vessel structure with convenient processing and novel and reliable structure has a positive significance in improving the market competitiveness of sterilizing products. In this paper, steam sterilizing pressure vessels are studied from three aspects: experimental research, theoretical analysis and numerical simulation. An experimental study was carried out on the original cylindrical pressure vessel by using the strain electric measurement method. When the experimental pressure is 0.35MPa, the principal strain of the measuring point can be obtained. According to the generalized Hook's law, the strain value can be converted into the stress value. Although there is a certain deviation between the measured value and the theoretical value, the deviation is small, and both of the results reflect the plane stress state of the thin-walled cylindrical pressure vessel and the disc head. The experimental results also provide a reference for the design of the new structure. Then, based on the infinite shell model, that is, ignoring the strengthening effect of the two ends cover, the analysis method of curved beam mechanics model is used to analyze the force of the rectangular vessel. By introducing the concept of flow radius, it is found that the dangerous section originates from the maximum flow radius, and the calculation formula of shell subjected to internal pressure and the strength check condition are derived. According to the calculation formula and engineering experience, the shell, head, nozzle and door of rectangular pressure vessel are designed in detail. The volume of the vessel is about 10L, the rounded angle between the four side plates is RX 30mm, the nominal thickness of the shell and the head is both 4mm, and the shell and the head are formed by integral stamping. The rectangular container is characterized by simple structure, easy processing, generous modeling and high space utilization. The structural static analysis of the designed vessel is carried out by the finite element analysis software ABAQUS,. In this paper, structured and swept meshes are used to divide the meshes, and the boundary conditions are loaded according to the actual working conditions. When the uniform pressure of 0.35MPa is loaded, the maximum equivalent stress on the vessel appears at the corner and then at the middle of the side plate. The circular corner is exactly the maximum flow radius, and the numerical simulation results are in agreement with the theoretical analysis. The results show that, in order to achieve the same strength grade as the cylindrical vessel, the wall thickness of the rectangular vessel increases, but its space utilization ratio is higher. Therefore, the rectangular container consumes less plates when the effective volume is equal. Overall, the use of rectangular containers does not significantly increase material consumption.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH49

【参考文献】