Stress and rigidity calculation method and system for straight-section outer guide cylinder

Abstract

The invention provides a stress and rigidity calculation method and system for a straight-section outer guide cylinder, and the method comprises the steps: firstly building a 1 / 2 symmetric mechanical model according to the symmetric structure characteristics and real load conditions of the straight-section outer guide cylinder; secondly, according to the 1 / 2 symmetric mechanical model, constructing a radial displacement and rotation angle formula of the straight-section outer guide cylinder; constructing a four-order matrix equation according to the radial displacement and a rotation angle formula, and solving to obtain a matrix solution; and finally, determining the stress and the axial rigidity of the straight-section outer guide cylinder based on the matrix solution. The established 1 / 2 symmetric mechanical model not only considers symmetric structure characteristics and real load conditions of the straight-section outer guide cylinder, but also considers discontinuous structure boundary influence, the straight-section outer guide cylinder is split into three basic elements for stress analysis, the axial rigidity of the straight-section outer guide cylinder is obtained through an accurate plate-shell theory solution, the axial rigidity of the straight-section outer guide cylinder is calculated through a precise plate-shell theory, and the accuracy of calculating the stress and rigidity of the outer guide cylinder is further improved.

Description

technical field [0001] The invention relates to the technical field of heat exchanger parameter design, in particular to a method and system for calculating stress and stiffness of a straight-section external flow guide cylinder. Background technique [0002] Heat exchangers are heat transfer equipment widely used in petroleum, chemical industry, and electric power. In order to better distribute the inlet fluid and improve heat transfer efficiency, an external flow guide cylinder is often installed on the shell side of the heat exchanger. Due to the convenience of processing and manufacturing, it has become one of the preferred structures in recent years. [0003] like figure 2 As shown, the current direct-section outer guide cylinder is composed of three basic elements: an end plate 1 , an outer shell 2 and an inner shell 3 . However, the design at home and abroad is too simplified and blind, and it is impossible to objectively evaluate the stress strength failure and saf...

AI Technical Summary

Problems solved by technology

However, the design at home and abroad is too simplified and blind, and it is impossible to objectively evaluate the stress strength failure and safety status of the guide tube. The neglect or unscientific calculation of the axial stiffness will bring safety hazards to the entire heat exchanger. The specific problems are as follows: 1. At present The engineering method only calculates the strength of the outer shell and the shell-side cylinder under internal pressure, and only calculates the primary stress intensity of the continuous structure, that is, the strength of the cylinder away from the discontinuous zone

2. The outer guide tube is a discontinuous structure, and the connection between the inner shell, the outer shell and the end plate is a geometric mutation area. The discontinuity of the structure leads to a high stress area, and the high stress area is the structurally dangerous part, ignoring the danger Part evaluation will bring security risks

3. In the current method, the strength of the end plate is guaranteed by the thickness ratio of the end plate to the outer shell. There is no scientific basis, and it is too blind, which is another safety hazard

However, the appearance of the straight-section outer guide cylinder changes the axial stiffness of the heat exchanger shell. The method provided in my country's GB / T`16749 "Pressure Vessel Corrugated Expansion Joint" is an approximate correction method and is not accurate enough.

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