The Unified Theory of Tubesheet Design - Part III: Comparison with ASME Method and Case Study

2021 ◽  
Author(s):  
Hong-Song Zhu ◽  
Jinguo Zhai ◽  
Guo-Yan Zhou
Keyword(s):  
Heat Exchangers ◽  
Numerical Comparison ◽  
Unified Theory ◽  
Element Analysis ◽  
Theoretical Comparison ◽  
Comparison Results ◽  
Different Types ◽  
Special Case ◽  
Simplified Mechanical Model

Abstract Based on the unified theory of tubesheet (TS) design for fixed TS heat exchangers (HEX), floating head and U-tube HEX presented in Part I and Part II, theoretical and numerical comparisons with ASME method are performed in this paper as Part III. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the unified theory. Numerical Comparison results indicate that predictions given by the unified theory agree well with finite element analysis (FEA), while ASME results are not accurate or not correct. Therefore, it is concluded that the unified theory deals with different types of HEX in equal detail with confidence to predict design stresses.

A Unified Analytical Method of Stress Analysis for Tubesheet—Part II: Case Study

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Hongsong Zhu
Keyword(s):  
Stress Analysis ◽  
Analytical Method ◽  
Heat Exchangers ◽  
Numerical Comparison ◽  
Element Analysis ◽  
Comparison Results ◽  
Different Types ◽  
The Unified Method ◽  
Unified Method

Based on the unified analytical method of stress analysis for fixed tubesheet (TS) heat exchangers (HEX), floating head and U-tube HEX presented in Part I, numerical comparisons with ASME method are performed in this paper as Part II. Numerical comparison results indicate that predictions given by the unified method agree well with finite element analysis (FEA), while ASME results are not accurate or not correct. Therefore, it is concluded that the unified method deals with thin TS of different types of HEX in equal detail with confidence to predict design stresses.

Refined General Theory of Stress Analysis for Tubesheet

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Hongsong Zhu
Keyword(s):  
General Theory ◽  
Stress Analysis ◽  
Heat Exchangers ◽  
Numerical Comparison ◽  
Refined Theory ◽  
Element Analysis ◽  
Comparison Results ◽  
Special Cases ◽  
Edge Conditions ◽  
Plate On Elastic Foundation

The stress analysis method for fixed tubesheet (TS) heat exchangers (HEX) in pressure vessel codes such as ASME VIII-1, EN13445, and GB151 is based on the classical theory of thin plate on elastic foundation. In addition, these codes all assume a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the unit or one TS is needed to be considered. In this study, a refined general theory of stress analysis for TS is presented which also considers unequal thickness for two TSs, different edge conditions, pressure drop and deadweight on two TSs, the anisotropic behavior of the TS in thickness direction, and transverse shear deformation in TS. Analysis shows floating and U-tube heat exchangers are the two special cases of the refined theory. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the refined theory. Numerical comparison results indicate that predictions given by the refined theory agree well with finite element analysis (FEA) for both thin and thick TS heat exchangers, while ASME results are not accurate or not correct. Therefore, it is concluded that the presented refined general theory provides a single unified method, dealing with both thin and thick TSs for different type (U type, floating, and fixed) HEXs in equal detail, with confidence to predict design stresses.

scholarly journals Analysis of Expansion Joint - A Case Study

2021 ◽  
Vol 9 (10) ◽  
pp. 45-51
Author(s):  
Prof. P R Subramaniam
Keyword(s):  
Variable Pressure ◽  
Pressure Loading ◽  
Ansys Software ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Pressure Load ◽  
Different Types ◽  
Comprehensive Modeling ◽  
Metallic Bellow

Abstract: Automotive, Aerospace, Pipeline industries widely use Bellows. Different types of bellows are used in these industries. The bellows are used for contraction or expansion applications. Repeated variable pressure loading and displacement on Metallic bellows joints results in bellows failure. This paper is a comprehensive modeling and analysis of an axial type exhaust metallic bellow due to varying pressure load and circumferential and radial displacement. All analysis completed using ANSYS software considering variable pressure load and cylindrical displacement as a boundary condition and perused the consequences. Stress distribution in the conditions of Case (i) variable pressure load and Case (ii) displacement are obtained. Keywords: ANSYS, FE Bellows, Finite Element Analysis, Bellow Failures

scholarly journals Stress Analysis and Design of Main Reducer Housing Using Finite Element Method

2018 ◽  
Vol 221 ◽  
pp. 04008
Author(s):  
S. Wang
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Numerical Comparison ◽  
Original Design ◽  
Element Analysis ◽  
Time Saving ◽  
Analysis And Design ◽  
Analysis Process ◽  
Comparison Results ◽  
Strength And Stiffness

The main reducer housing takes over the shaft loads from gear engagement and transmits to other components, such as differential, semiaxle and driving wheels, so the main reducer housing with enough strength and stiffness is very important. Some factors preventing it from failure need to be taken into consideration when design it. To design a main reducer housing with better performance, in this paper, FEA (Finite Element Analysis) is used to analysis the main reducer housing and to find out some big stress regions. Then, some modifications are proposed to eliminate those big stress regions and obtain a reliable main reducer housing. During the analysis process, an annulus model is built and the reaction forces between the differential bearing seats and axle housing are calculated to determine whether they contact with each other. Finally, some design methods and improvements of the original design main reducer housing are proposed. And numerical comparison results of the stress distribution of the original and improved main reducer housing validate the effectiveness of the proposed methods and modifications in this paper. Those stress analysis and modifications in this paper are time-saving and money-saving before mass production.

The Unified Theory of Tubesheet Design - Part I: Theoretical Foundation

2021 ◽  
Author(s):  
Hong-Song Zhu ◽  
Jinguo Zhai
Keyword(s):  
Theoretical Foundation ◽  
Numerical Comparison ◽  
Unified Theory ◽  
Shell Side ◽  
Dead Weight ◽  
Element Analysis ◽  
Structure Comparison ◽  
Temperature Growth ◽  
Wide Range ◽  
Flow Pressure

Abstract The unified theory of tubesheet (TS) design for fixed TS heat exchangers (HEX), floating head and U-tube HEX is presented by removing the mid-plane symmetry (MPS) assumption, which assumes a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the HEX or one TS need be considered. All common types of HEXs, with arbitrary combinations of TS configurations, and with arbitrary geometric, material properties and temperature for each component are considered by the unified theory. The effects of unperforated annual plate, TS flange, gravitational (e.g. dead-weight of tubes, catalyst inside tubes, shell side fluid and tube side fluid) and fluid flow pressure loss, bending stiffness of the tubes, TS in-plane stretch, pressure in TS perforations, differential temperature growth in TS radial direction as well as the temperature gradient in TS thickness direction are also evaluated by the unified theory. Theoretical analysis shows that existing theories of TS design can be derived from the unified theory as special deductions. Structure comparison shows the unified theory covers a wide range of applicable HEX configuration well beyond existing theories. Numerical Comparison indicates that predictions given by the unified theory agree well with finite element analysis (FEA), while ASME results are not accurate or not correct.

scholarly journals Environmental enrichment for primates in laboratories

2011 ◽  
Vol 5 (1) ◽  
pp. 41-56 ◽  
Author(s):  
H. M. Buchanan-Smith
Keyword(s):  
Natural History ◽  
Environmental Enrichment ◽  
Critical Component ◽  
Study Protocols ◽  
Different Types ◽  
Need To Evaluate ◽  
And Control ◽  
Special Case

Abstract. Environmental enrichment is a critical component of Refinement, one of the 3Rs underlying humane experimentation on animals. In this paper I discuss why primates housed in laboratories, which often have constraints of space and study protocols, are a special case for enrichment. I outline a framework for categorising the different types of enrichment, using the marmoset as a case study, and summarise the methods used to determine what animals want/prefer. I briefly review the arguments that enrichment does not negatively affect experimental outcomes. Finally I focus on complexity and novelty, choice and control, the underlying features of enrichment that makes it successful, and how combined with a thorough understanding of natural history we can put effective enrichment into practice in laboratories. Throughout the paper I emphasise the need to evaluate enrichment to ensure it is having the desired effect.

A Unified Analytical Method of Stress Analysis for Tubesheet—Part I: Theoretical Foundation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Hongsong Zhu
Keyword(s):  
Stress Analysis ◽  
Analytical Method ◽  
Numerical Comparison ◽  
Design Standards ◽  
Element Analysis ◽  
Technical Literature ◽  
Edge Conditions ◽  
The Unified Method ◽  
Special Case ◽  
Unified Method

Based on a brief review of existing tubesheet (TS) design standards and the pertinent technical literature, a unified analytical method of stress analysis for fixed TS heat exchangers (HEXs), floating head and U-tube HEXs is proposed by removing the midplane symmetry (MPS) assumption, which assumes a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the HEX or one TS needs be considered. The unified method can be successfully extended to the situations for different TS materials, unequal TS thicknesses, different TS edge conditions, different TS temperatures, pressures drop and dead weights on two TSs. The effects of pressure in TS perforations and temperature gradient in TS thickness direction are also considered by the unified method. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the unified method. Numerical comparison indicates that predictions given by the unified method agree well with finite element analysis (FEA), while ASME results are not accurate or not correct.

Finite Element Analysis and Experimental Investigation of Tubesheet Structure

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
C. F. Qian ◽  
H. J. Yu ◽  
L. Yao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Heat Exchangers ◽  
Thermal Load ◽  
Axial Strain ◽  
Element Analysis ◽  
Shell Elements ◽  
Different Types ◽  
Analysis Models

In order to investigate the possibility of numerical simulation for whole structures of heat exchangers, two finite element analysis models have been established for the fixed tubesheet structure composed of tubesheet, cylindrical shell, and tubes using different types of elements. Stresses and deformations produced by pressure load or thermal load are calculated, and the axial strain at the middle area of the cylindrical shell is experimentally measured. By comparing the numerical results with experimental measurements, it is found that both finite element analysis models can give satisfactory results. Considering the difficulties in modeling heat exchangers, beam and shell elements are recommended.

Design of Unpartitioned, Plug Type Header Boxes for Air-Cooled Heat Exchangers in Refinery Service

2012 ◽  
Author(s):  
Hugh-Jean Nel ◽  
Alan Nurick ◽  
André Leon Nel ◽  
Francois Lombaard
Keyword(s):  
Heat Exchangers ◽  
Theory Model ◽  
American Petroleum Institute ◽  
Element Analysis ◽  
Cooling Systems ◽  
Rigid Frame ◽  
Division 1 ◽  
Section Viii ◽  
Accurate Stress Analysis

Dry air-cooled heat exchangers (ACHE) form an integral part of refinery cooling systems of which the header boxes form an important component. It is commonly designed as an ASME Section VIII Division 1 pressure vessel, but unfortunately neither ASME nor the American Petroleum Institute (API) provide guidance regarding to the methodology which should be used in the assessment of nozzle loads on the header box design. Subsequently, the designer must rely either on empirical guidelines or Finite Element Analysis (FEA) in line with the requirements of ASME Section VIII U-2(g). The aim of this project therefore was to develop an analytical design methodology that accounts for the effects of these nozzle loads on the header box. A new mechanical model was derived by extending the existing ASME Section VIII rigid frame theory model and the result was tested against an FEA case study to determine whether the model was useable. It was found that the new model makes some useful qualitative statements but cannot be used for accurate stress analysis of the stresses near the base of the nozzle on the header box. The case study was also used to examine the effectiveness of a commonly used empirical guideline.

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