CFD and Thermo-Mechanical Analysis for Heat Exchanger Used in Aero Engine

Author(s):  
Ho Seung Jeong ◽  
Jong Rae Cho ◽  
Lae Sung Kim ◽  
Man Yeong Ha ◽  
Ji Hwan Jeong ◽  
...  

The multi-physics analysis using both the CFD and thermo-mechanical analysis is carried out to estimate the life of the heat exchanger which is operated under the conditions of high temperature and high pressure. First CFD analysis is carried out to obtain the distribution of flow, pressure and temperature around heat exchanger. The distribution of pressure, temperature and heat transfer coefficient obtained from the CFD analysis is transferred to the thermo-mechanical analysis using finite element analysis technique and is used as data to calculate the mechanical and thermal stress distribution in the heat exchanger. For the CFD analysis, it is considered a segment of heat exchangers using the symmetric and periodic conditions. For the thermo-mechanical analysis, the present finite element model considered both a segment and a half of full geometry by using the symmetric and periodic conditions. Alloy 625 is used for the present heat exchanger design due to its high strength at the elevated temperatures. The temperature-dependent physical properties of Alloy 625 for the thermo-mechanical analysis are used in a temperature ranges of 300∼1100K. Fatigue analysis is performed using a Goodman-diagram to assess the life of the present heat exchanger.

2008 ◽  
Vol 44-46 ◽  
pp. 529-536
Author(s):  
Biao Yuan ◽  
Y.Z. Wang ◽  
X. Ma ◽  
Yang Yan Zheng ◽  
Shan Tung Tu

Zirconium tube is widely used in heat exchanger equipments in petrochemical process for significant corrosion resistance. The connection joint of tube-tubesheet is the weakest parts in a heat exchanger. The experiment and numerical analysis of different materials (zirconium tubes, titanium tubes and 16MnR tubesheets, 316L tubesheet) joints were performed in this paper. The expansion joints specimens were prepared at the pressure ranging from 28MPa to 38MPa. And pulling out test was performed from 20°C to 300°C. The finite element model of tube-tubesheet joint was established. The effect of expansion pressure, temperature and groove on the pulling out strength of joints was analyzed. Both the experiments and the finite element analysis show that the pull-out strength increases with the increasing expansion pressures. Working temperature also has a great effect on the connection strength of tube-to-tubesheet joints, especially for the zirconium and 316L joints, which have the most significant difference of thermal expansion coefficient between tube and tubesheet. The residual contacting pressure on the contact surface between tubes and the tubesheet is not uniformly distributed and two tightness bands are found near the surfaces of the tubesheet or at the two brinks of the groove on the tubesheet hole. Compared with the ungrooved joint, the residual contacting pressure on the tightness bands for the grooved joint is much higher, indicating a grooved joint has better tightness.


2017 ◽  
Vol 29 (5) ◽  
pp. 896-904 ◽  
Author(s):  
Duo Yi ◽  
Min Zhang ◽  
Lijuan Gu ◽  
Jianming Yang ◽  
Wenhui Yu

This study aims to evaluate the thermomechanical behavior of a new composite structure using finite element method. The composite structure consists of the substrate and the thermal spray coating with embedded fiber optic. The temperature evolution of the composite estimated by the finite element model shows good agreement with the experimental recording, which confirms the justifiability of model initialization, and then, the thermal results are applied for the following mechanical analysis. The stress distribution and the variation in refractive index of the embedded fiber are investigated. The results show that the stress level suffered by the embedded fiber is much lower than the yield strength, and the variation in refractive index of the embedded fiber has an insignificant effect on optical transmission, which ensures a good embedding quality of the fiber optic.


Author(s):  
Eduardo Ribeiro Malta ◽  
Clóvis de Arruda Martins

Axial compressive loads can appear in several situations during the service life of a flexible pipe, due to pressure variations during installation or due to surface vessel heave. The tensile armor withstands well tension loads, but under compression, instability may occur. A Finite Element model is constructed using Abaqus in order to study a flexible pipe compound by external sheath, two layers of tensile armor, a high strength tape and a rigid nucleus. This model is fully tridimensional and takes into account all kinds of nonlinearities involved in this phenomenon, including contacts, gaps, friction, plasticity and large displacements. It also has no symmetry or periodical limitations, thus permitting each individual wire of the tensile armor do displace in any direction. Case studies were performed and their results discussed.


Author(s):  
N. Rino Nelson ◽  
N. Siva Prasad ◽  
A. S. Sekhar

Gasketed flange joint is a vital component in pressure vessels and piping systems. Flange joint is usually subjected to bending load due to expansion, wind load, self-weight, etc. Most of the flange design methods use equivalent pressure to include the effect of external bending loads. It becomes complex when the joint is subjected to bending load at elevated temperatures, due to the nonlinear behavior of gasket material. In the present work, performance of the flange joint has been studied under external bending load at elevated temperatures. A 3D finite element model is developed, considering the nonlinearities in the joint due to gasket material and contact between its members along with their temperature dependent material properties. The performance of the joint under different bolt preloads, internal fluid pressures and temperatures is studied. Flange joint with two gaskets (twin gasketed joint) placed beside each other radially, is also analyzed under external bending moment. The maximum allowable bending moments at different internal temperatures, for single and twin gasketed joints with spiral wound gasket are arrived.


2012 ◽  
Vol 590 ◽  
pp. 487-491
Author(s):  
Qin Man Fan

The frame is the main part of the force matrix of truck vehicle and the stress state is complex and difficult to design. The finite element method is more accurate for the analysis of the static and dynamic characteristics of the frame, which provide guidance for the frame structure design. Establish finite element model of the frame with the application of ANSYS. According to the mechanical analysis of the model, impose reasonable constraints and load, the most typical of the four conditions in the frame is calculated with the finite element analysis, and predicted the weak parts of the frame according to the frame stress-strain cloud, which provided a very important theoretical basis for the improvement of the frame structure of the frame and optimizing design of the frame.


Author(s):  
Nicolas A. DeLovato ◽  
Kevin J. Albrecht ◽  
Clifford K. Ho

Abstract A focus in the development of the next generation of concentrating solar power (CSP) plants is the integration of high temperature particle receivers with improved efficiency supercritical carbon dioxide (sCO2) power cycles. The feasibility of this type of system depends on the design of a particle-to-sCO2 heat exchanger. This work presents a finite element analysis (FEA) model to analyze the thermal performance of a particle-to-sCO2 heat exchanger for potential use in a CSP plant. The heat exchanger design utilizes a moving packed bed of particles in crossflow with sCO2 which flows in a serpentine pattern through banks of microchannel plates. The model contains a thermal analysis to determine the heat exchanger’s performance in transferring thermal energy from the particle bed to the sCO2. Test data from a prototype heat exchanger was used to verify the performance predictions of the model. The verification of the model required a multitude of sensitivity tests to identify where fidelity needed to be added to reach agreement between the experimental and simulated results. For each sensitivity test in the model, the effect on the performance is discussed. The model was shown to be in good agreement on the overall heat transfer coefficient of the heat exchanger with the experimental results for a low temperature set of conditions with a combination of added sensitives. A set of key factors with a major impact on the performance of the heat exchanger are discussed.


2014 ◽  
Vol 611-612 ◽  
pp. 1753-1762 ◽  
Author(s):  
Elena Silvestre ◽  
Eneko Sáenz de Argandoña ◽  
Lander Galdos ◽  
Joseba Mendiguren

Roll levelling is a forming process used to remove the residual stresses and imperfections of metal strips by means of plastic deformations. During the process the metal fibres are subjected to cyclic tension-compression deformations leading to achieve flat product. The process is especially important to avoid final geometrical errors when coils are cold formed or when thick plates are cut by laser. In the last years, and due to the appearance of high strength materials such as Ultra High Strength Steels, machine design engineers are demanding a reliable tool for the dimensioning of the levelling facilities. In response to this demand, Finite Element Analysis and Analytical methods are becoming an important technique able to lead engineers towards facilities optimization through a deeper understanding of the process. Aiming to this study two different models have been developed to analyze the roll levelling operations: an analytical model and a finite element model. The FE-analysis was done using 2D-modelling assuming plane strain conditions. Differing settings, leveller configuration and materials were investigated. The one-dimensional analytical levelling model is based on classical beam theory to calculate the induced strain distribution through the strip, and hence the evolving elastic/plastic stress distribution. Both models provide a useful guide to process-sensitivities and are able to identify causes of poor leveller performance. The theoretical models have been verified by a levelling experimental prototype with 13 rolls at laboratory.


2014 ◽  
Vol 607 ◽  
pp. 286-289
Author(s):  
Hai Fei Qiu ◽  
Song Lin Wu ◽  
Hong Cai Yang

Trough roller is an important component part on belt conveyor, the carrying capacity of the roller is a basis of belt conveyor. The calculation principle and method of material’s cross section area is deduced in the thesis, and mechanical analysis of the trough roller is carried out based on that, in results, the static load of it is calculated. The finite element model of the trough roller is set up by Simulation /Works software, and then the stress and deformation results of it is clear through finite element statics calculation and analysis. Based on this thesis, some valuable basis and reference are offered to trough roller’s strength and stiffness design.


Author(s):  
Long Ju ◽  
Shrinivas Patil ◽  
Jim Dykeman ◽  
Taylan Altan

Aluminum alloys are increasingly used in automotive manufacturing to save weight. The drawability of Al 5182-O has been proven at room temperature (RT) and it is also shown that formability is further enhanced at elevated temperatures (ETs) in the range of 250–350 °C. A cost effective application of ET forming of Al alloys can be achieved using heated blank and cold dies (HB–CD). In this study, the material behavior of Al 5182-O is characterized using tensile test and viscous bulge test at RT. The nonisothermal finite element model (FEM) of deep drawing is developed using the commercial software pamstamp. Initially, deep drawing simulations and tests were carried out at RT using a 300 ton servo press, with a hydraulic cushion. The predictions with flow stress curves obtained from tensile and bulge tests were compared with experimental data. The effect of punch speed and temperature rise during forming at RT is investigated. The warm forming simulations were carried out by combining material data at ETs obtained from the literature. The coupled effects of sheet temperatures and punch speeds are investigated through the finite element analysis (FEA) to provide guidelines for ET stamping of Al 5182-O.


Author(s):  
Gary A. Anderson ◽  
Corey M. Lanoue ◽  
Fereidoon Delfanian

In order to ensure rifle barrels have the features of high strength, durability, and light weight, the strength analysis of the barrels under hot temperatures and pressures is very important in the design. A finite element model incorporating the plastic deformation of a typical 0.50 caliber rifle barrel is constructed to determine the stresses caused by the mechanical loads and plastic deformation. According to the simulation results, the finite element analysis is proved to be a power analysis tool for future failure analysis of firearm barrels. The method provides a power tool for analysis of firearm barrels. The projectile was accelerated to 941.7 m/s in 1.430 ms with a pressure profile that reached a maximum of 469.3 MPa. Stresses as large as 1,410 MPa along the interior of the barrel were found where the leading edge of the projectile slides along the bore, but the largest stresses at the exterior of the barrel were found where the barrel wall is thinnest near the chamber.


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