scholarly journals Improved Analysis on the Fin Reliability of a Plate Fin Heat Exchanger for Usage in LNG Applications

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3624
Author(s):  
Mustansar Hayat Saggu ◽  
Nadeem Ahmed Sheikh ◽  
Usama Muhamad Niazi ◽  
Muhammad Irfan ◽  
Adam Glowacz ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Exchanger ◽  
Temperature Gradient ◽  
Large Temperature ◽  
The Finite Element Method ◽  
Lower Face ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Liquefaction Process

A plate fin heat exchanger (PFHE) is a critical part of the cryogenic industry. A plate fin heat exchanger has many applications, but it is commonly used in the liquefied natural gas (LNG) industry for the gasification/liquefaction process. During this gasification to the liquefaction process, there is a large temperature gradient. Due to this large temperature gradient, stresses are produced that directly influence the braze joint of PFHE. Significant work has been carried out on heat transfer and the flow enhancement of PFHE; however, little attention has been paid to structural stability and stresses produced in these brazed joints. Due to these stresses, leakages in PFHE are observed, mostly in braze joints. In the current study, standard fin design is analyzed. In addition, the structural stability of brazed joints under standard conditions is also tested. Two techniques are used here to analyze fins, using the finite element method (FEM), first by examining the whole fin brazed joint on the basis of experimentally calculated yield strength and second by dividing the braze seam into three sections and defining individual strength for each section of the seam to find stress magnitude on the basis of heat-affected zones. Moreover, by using two different techniques to analyze brazed joints, the stresses in the lower face of the brazed joint were increased by 13% and decreased by 18% in the upper face using different zone techniques as compared to standard full braze seam analysis. It can be concluded that different zone techniques are better in predicting stresses as compared to simple full braze seam analysis using the finite element method since stresses along the lower face are more critical.

scholarly journals Assessment of the Technical Condition of the Emergency Heat Exchanger for the Reactor Plant of the B-320 Type in Order to Extend Its Service Life

2021 ◽  
pp. 36-43
Author(s):  
Valeriy Konshin ◽  
Mikola Zaiats
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Exchanger ◽  
Nuclear Power ◽  
Power Plants ◽  
Technical Condition ◽  
Operating Conditions ◽  
Preliminary Evaluation ◽  
The Finite Element Method ◽  
Element Method

Extending the life of nuclear power plants in Ukraine during in the super-project period, as in most countries operating nuclear power units, is an accepted strategy and is being implemented practically. In this regard, there is a need for verification calculation of the main elements The calculated analysis of the stress-strain state of the heat exchanger is carried out using the finite element method of power equipment that determine the resource characteristics. The technical condition of the emergency cooling heat exchanger  for the power unit no. 3 of the SUNPP has been evaluated. The analysis of design, technical and operational documentation in the amount of preliminary evaluation of technical condition was performed. Potential mechanisms of wear of heat exchanger elements were determined. The technique of carrying out verification calculations for static, cyclic and seismic stability was described. The emergency cooling heat exchanger calculation model is made in the APM Structure 3D calculation code. The tense-deformed state of the heat exchanger is calculated using the finite-element method of resampling the design region.  The results of the verification calculation of the emergency cooling heat exchanger in the calculated states corresponding to normal operating conditions, hydrotests and under seismic impacts in conditions of the maximum design earthquake were presented.  The correspondence of the actual stresses in the calculation zones of the heat exchanger to the permissible values, specified in the current regulatory documentation was established. The amount of damageability to the heat exchanger elements was determined for the permissible number of load cycles. The cyclical strength of the elements of the emergency cooling heat exchanger, taking into account the period of application equal to 60 years inclusive, is ensured in accordance with the requirements.

scholarly journals A novel method for calculating effective thermal conductivity of particulate fouling

2019 ◽  
pp. 308-308
Author(s):  
Zhong-Bin Zhang ◽  
C Congyu ◽  
Yang Liu ◽  
Li-Hua Cao
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Method ◽  
Finite Element ◽  
Heat Exchanger ◽  
Effective Thermal Conductivity ◽  
Parametric Design ◽  
The Finite Element Method ◽  
Particulate Fouling ◽  
Novel Method ◽  
Element Method

The accurate thermal conductivity of fouling plays a very significant role in designing heat exchanger. In this paper, a novel method of calculating the effective thermal conductivity (ETC) of particulate fouling is put forward by using Image-Pro-Plus image processing, the finite element method and ANSYS parametric design language (APDL). First of all, according to the analysis on the particulate fouling samples features, the particulate fouling is considered as porous media with fractal characteristics, whose microscopic network model is established using the finite element method, and each unit body material properties are randomly assigned by APDL. Secondly, ETC of particulate fouling model is calculated by the steady state plate method. And then, the influence of particulate fouling microstructure on ETC is explored. Last, it is also show that the calculation resulting of ETC agrees well with available experimental data and empirical correlation. Moreover, it has been shown that ETC of particulate fouling is closely associated with the porosity and pore size. The method can be used to research on the thermal conductivity of fouling, discuss the influence of microstructure on ETC of fouling, and provide the guidelines for designing of heat exchanger on calculating accurate thermal conductivity of fouling.

scholarly journals The plane-to-cellular-to-dendrite transition of the shape of the crystallization front during the crystallization of Al-Cu alloys

2006 ◽  
Vol 71 (3) ◽  
pp. 303-312
Author(s):  
Vesna Radojevic ◽  
Andreja Valcic ◽  
Slobodanka Nikolic ◽  
Aleksandar Golubovic
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Crystal Growth ◽  
Temperature Gradient ◽  
Crystallization Front ◽  
The Finite Element Method ◽  
Cu Alloys ◽  
Vertical Bridgman

The evolution of the crystallization front from a planar to a dendritic one as a function of the G L/(Rc 0) parameter was investigated during the crystallization of Al-Cu alloys by the vertical Bridgman method. Six series of alloys with different initial compositions of Cu were solidified at different growth rates. A mathematical model for the heat transfer during vertical Bridgmen crystal growth was developed. The model was solved using the finite element method. The temperature gradient in the melt at the beginning of crystal growth was calculated using the obtained model. Discrete stages of the crystallization front were identified in the experiments, as the ratio G L/(Rc 0) decreased.

Dynamic Fracture Behavior of 316L Brazed Joint: Study With Experimental and Finite Element Methods

2018 ◽  
Author(s):  
Weiya Zhang ◽  
Wenchun Jiang ◽  
Bin Yang ◽  
Ming Song ◽  
Xiangnan Zhai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain Rate ◽  
Dynamic Fracture ◽  
Fracture Behavior ◽  
Dynamic Pressure ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Axial Fracture ◽  
Element Method

Brazed joints are widely used in the plate fin structures, and it is very important to ensure the strength under dynamic pressure. This paper investigated the dynamic fracture mechanism of 316L brazed joints using experimental and finite element method. Results show that the yield strength, tensile strength and elongation of the brazed joint are closely related with the strain rate. Using the finite element method, the strain rate sensitive model (Johnson-Cook) is built, and the brazed joint shows a multi-axial fracture mode. Meanwhile, the brazed residual stress and filler metal thickness affect the dynamic fracture behavior of the brazed joint.

scholarly journals Operation analysis of a spiral ground heat exchanger functioning as a lower heat source in a pressurizing heat pump

2018 ◽  
Vol 21 ◽  
pp. 00022
Author(s):  
Damian Mazur ◽  
Robert Smusz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Ground Heat Exchanger ◽  
The Finite Element Method ◽  
Heating Period ◽  
Operation Analysis ◽  
Spiral Heat Exchanger ◽  
Lower Heat

The main aim of the study is to identify functioning of a ground, spiral heat exchanger co-functioning with a pressurizing heat pump. The heat pump is connected with a heat battery and works periodically during the heating period. The analysis was made by means of numerical modelling and using the finite element method.

Design and Analysis of Open Rack LNG Vaporizer

2004 ◽  
Author(s):  
Norihiro Hisada ◽  
Masaru Sekiguchi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Heat Exchanger ◽  
Numerical Analysis ◽  
External Surface ◽  
Design Method ◽  
Thermal Design ◽  
The Finite Element Method ◽  
Significant Difference

The dominating LNG Vaporizer is the Open Rack Vaporizer, which uses seawater for the heat source. This Vaporizer is designed to exchange heat between LNG of −160°C and seawater of ambient temperature, thus resulting in phenomena such as the vaporization of LNG inside heat exchanger tubes and the icing of seawater on the external surface of the heat exchanger tubes, which brings about difficulties in the thermal design. Since the ORV is the heat exchanger that makes a significant difference in temperature and needs a rapid startup or shutdown, appropriate considerations should be given to thermal stress. In this connection, through a variety of tests or analysis by the finite element method, highly endurable structures have been established. The thermal design method making it possible to design best-suited shapes (e.g. sizes and internal/external surface shapes) of the heat exchanger tubes through the use of numerical analysis and the thermal stress design of ORV is introduced hereunder.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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