Strength Evaluation of LNG Containment System Considering Fluid-Structure Interaction Under Sloshing Impact Pressure

2007 ◽  
Author(s):  
Bo Wang ◽  
Jang Whan Kim
Keyword(s):  
Comparative Method ◽  
Fluid Structure Interaction ◽  
Operating Conditions ◽  
Impact Pressure ◽  
Acoustic Medium ◽  
Strength Evaluation ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Containment System ◽  
Membrane Type

As LNG carriers become larger and new operating conditions are being designed, it is essential to develop a new procedure for the strength evaluation of a membrane-type LNG containment system under sloshing loads. The conventional comparative method based on existing service experiences and previous damage cases is currently used in most cases, but this method is only valid for designing new LNG carriers with similar size and type of existing ones. In this study, an analytical solution of acoustic-solid interaction has been derived and a simple 2D coupled acoustic-solid model has been simulated to investigate hydro-elastic effects for the verification purpose. After validation of FE modeling, a coupled model considering the fluid-structure interaction between LNG and containment system has been developed for structural analysis of LNG Mark III containment system. For LNG Mark III containment system, nonlinear dynamic FE analysis under sloshing impact pressure has been conducted using the fluid-structure coupling model. In FE simulations, the hydro-elastic effect in structural response has been studied through considering LNG as an acoustic medium, foam as a visco-elastic material, plywood as an orthotropic material, and mastic as an isotropic material. Parametric study has also been done to investigate the effects of material properties and loading patterns on hydro-elastic response in the coupled fluid-structure model. Based on FE results and experimental data, the strength of LNG Mark III containment system has been evaluated in terms of acceptance criteria. Finally, the new procedure has been developed for the strength evaluation of membrane-type LNG containment systems.

A Direct Assessment Approach for Structural Strength Evaluation of Cargo Containment System Under Sloshing Inside LNGC Tanks Based on Fluid Structure Interaction

2008 ◽  
Author(s):  
Hisashi Ito ◽  
Yongsuk Suh ◽  
Sangeon Chun ◽  
Y. V. Satish Kumar ◽  
Munkeun Ha ◽  
...  
Keyword(s):  
Structural Strength ◽  
Fluid Structure Interaction ◽  
Structural Safety ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Direct Assessment ◽  
Containment System ◽  
Assessment Approach ◽  
Technical Issues ◽  
Membrane Type

The sloshing phenomenon is one of the most important and challenging issues for the design of cargo containment systems of LNG carriers and is being studied by various research groups in many countries. In this paper, a direct assessment approach based on fluid structure interaction is proposed to assess the structural safety of cargo containment systems against extreme sloshing loads. In the course of developing the methodology, two technical issues are mainly dealt with; (1) how to efficiently apply a numerical method for sloshing phenomena and (2) how to verify the structural safety criteria of cargo containment system against sloshing. The developed methodology is applied to a membrane-type cargo containment system of a large LNG carrier built in Samsung Shipyard.

Experimental and Numerical Investigation Into the Effects of Fluid-Structure Interaction on the Sloshing Impact Loads in Membrane LNG Carrier

2008 ◽  
Author(s):  
Jong-Jin Jung ◽  
Hyun-Ho Lee ◽  
Tae-Hyun Park ◽  
Young-Woo Lee
Keyword(s):  
Numerical Simulations ◽  
Numerical Study ◽  
Fluid Structure Interaction ◽  
Impact Pressure ◽  
Natural Period ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Pressure Peak ◽  
Membrane Type ◽  
The Impact

The hydro-elasticity effect of sloshing loads in LNG cargo tank has been studied through experiments and numerical simulations regarding the fluid-structure interaction between sloshing impact pressures and tank structures. Sloshing model tests with 1/50 scale membrane type tanks were carried out for 1-D regular harmonic motion to investigate variations of impact pressures due to elasticity differences of the tank structure. Numerical simulations were performed and validated for the same case. Additionally, wall impinging jet flow was simulated by numerical simulation to verify the relation between elasticity of structure and impact pressure. It was commonly observed that the elasticity of the tank structure had significant influence on the height and shape of the impact pressure peak. Numerical study showed that the ratio between the structural natural period and the duration of the impact pressure is important for the influence of impact pressure on the tank structure.

scholarly journals Simulation of 2-Way Fluid Structure Interaction in a 3D Model Combustor

2012 ◽  
Author(s):  
Mina Shahi ◽  
Jim B. W. Kok ◽  
P. R. Alemela
Keyword(s):  
Flue Gas ◽  
Fluid Structure Interaction ◽  
Operating Conditions ◽  
Limit Cycle Oscillation ◽  
Structural Domain ◽  
Pressure Oscillations ◽  
Fluid Structure ◽  
Thermoacoustic Instability ◽  
Structure Interaction ◽  
Computational Fluid Dynamics Analysis

The liner of a gas turbine combustor is a very flexible structure that is exposed to the pressure oscillations that occur in the combustor. These pressure oscillations can be of very high amplitude due to thermoacoustic instability, when the fluctuations of the rate of heat release and the acoustic pressure waves amplify each other. The liner structure is a dynamic mechanical system that vibrates at its eigenfrequencies and at the frequencies by which it is forced by the pressure oscillations to which it is exposed. On the other hand the liner vibrations force a displacement of the flue gas near the wall in the combustor. The displacement is very small but this acts like a distributed acoustic source which is proportional to the liner wall acceleration. Hence liner and combustor are a coupled elasto-acoustic system. When this is exposed to a limit cycle oscillation the liner may fail due to fatigue. In this paper the method and the results will be presented of the partitioned simulation of the coupled acousto-elastic system composed of the liner and the flue gas domain in the combustor. The partitioned simulation uses separate solvers for the flow domain and the structural domain, that operate in a coupled way. In this work 2-way fluid structure interaction is studied for the case of a model combustor for the operating conditions 40–60 kW with equivalence ratio of 0.625. This is done in the framework of the LIMOUSINE project. Computational fluid dynamics analysis is performed to obtain the thermal loading of the combustor liner and finite element analysis renders the temperature, stress distribution and deformation in the liner. The software used is ANSYS workbench V13.0 software, in which the information (pressure and displacement) is also exchanged between fluid and structural domain transiently.

The Ocean Cleanup System 001 Performance During Towing and Seakeeping Tests

2019 ◽  
Author(s):  
Joost Sterenborg ◽  
Nicola Grasso ◽  
Rogier Schouten ◽  
Arjen Tjallema
Keyword(s):  
Fluid Structure Interaction ◽  
Model Tests ◽  
Operating Conditions ◽  
Image Correlation ◽  
Plastic Pollution ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Floating System ◽  
Floating Systems

Abstract One of the aims of The Ocean Cleanup is to develop technologies to extract plastic pollution from the world’s oceans. Several concepts of passive floating systems were considered that are supposed to confine plastics to ease their collection. Such concepts consist of a floating member and a submerged flexible skirt and have in common that their span is generally more than 500 meters. Consequently, fluid-structure interaction plays an important role in the response of such a floating system. To support numerical simulations, MARIN carried out extensive model tests on a 120 meter system section of the final concept, with focus on the fluid-structure interaction (FSI) of the submerged skirt in operating conditions and in towing configuration. The ability to capture plastics was not investigated in these model tests. Novel for wave-basin tests were non-intrusive measurements using underwater Digital Image Correlation (DIC) to obtain the displacements and deformations of the flexible skirt. DIC proved to be a capable measurement technique for this type of structure in combination with a wave basin. Detailed quantitative data on skirt motions and deformations were delivered and the last concept of the cleanup system was tested in the towing configuration and operational configuration.

Seismic Analysis of a Nuclear Reactor With Fluid-Structure Interaction

2005 ◽  
Author(s):  
Jean-Franc¸ois Sigrist ◽  
Daniel Broc ◽  
Christian Laine
Keyword(s):  
Internal Structure ◽  
Pressure Vessel ◽  
Nuclear Reactor ◽  
Seismic Analysis ◽  
Mass Operator ◽  
Fluid Structure Interaction ◽  
Added Mass ◽  
Operating Conditions ◽  
Fluid Structure ◽  
Structure Interaction

The present paper is related to a seismic analysis of a naval propulsion ground prototype nuclear reactor with fluid-structure interaction modeling. Many numerical methods have been proposed over the past years to take fluid/structure phenomenon into account [14] in various engineering domains, among which nuclear engineering in seismic analysis [15]. The purpose of the present study is to apply general methods on a global approach of the nuclear reactor. A simplified design of the pressure vessel and the internal structure is presented; fluid-structure interaction is characterized by the following effects: • added mass effects are highlighted with the calculation of an added mass operator, obtained from a finite element discretisation of the coupled problem. The numerical model is developed within the CASTEM code using an axi-symmetric model of the industrial structure; • coupling effects between the external and internal structure via the confined inner fluid are also illustrated and numerically described with the added mass operator; • added stiffness effects are taken into account with an added stiffness matrix describing pre-stress effects due to a static pressure loading simulating the actual operating conditions of the reactor. The expected fluid-structure interaction effects on the nuclear pressure vessel and their numerical modeling leads to the definition of a global coupled model which can be used to perform a seismic analysis. A modal analysis is first performed and classical linear methods (static, spectral and temporal) are then applied on the studied structure with taking fluid-structure into account.

Numerical Evaluation of Deformation and Stress in Impellers of Multistage Pumps by Means of Fluid Structure Interaction

2013 ◽  
Author(s):  
Andreas Schneider ◽  
Björn-Christian Will ◽  
Martin Böhle
Keyword(s):  
Numerical Evaluation ◽  
Fluid Structure Interaction ◽  
Hydrodynamic Pressure ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Design Parameters ◽  
Centrifugal Pumps ◽  
Fluid Structure ◽  
Structural Part ◽  
Structure Interaction

The operational reliability of centrifugal pumps strongly depends on an adequate structural design of every single component. Therefore, the design process requires trustworthy information about the expected stresses and deformations. The numerical evaluation of the deformations and the stresses in the impellers of multistage centrifugal pumps is the topic of this report. The loads acting on the impeller under operating conditions can be subdivided into structural and hydrodynamic components, which are considered by means of one-way coupled fluid-structure interaction (FSI) simulations. For the investigations, an exemplary multistage pump with a specific speed of nq = 30 has been chosen. The hydrodynamic pressure loads on the impeller are derived from the CFD solution for a single stage of the pump. These pressure loads are imposed on the impeller in the structural part of the simulation. In order to determine the resulting deformations and stresses of the impeller, static structural analyses are performed. Different operating conditions, i.e. flow rates and temperatures, are analyzed. Furthermore, the influence of structural impeller design parameters on the resulting deformations and stresses is investigated in detail. The thickness of the impeller shrouds as well as the fillet radii between the blades and the shrouds are considered as design parameters.

Study of coating's effects on mechanical performances for sleeve of cotton picker with fluid–structure interaction method

2014 ◽  
Vol 228 (17) ◽  
pp. 3057-3068 ◽  
Author(s):  
FM Meng ◽  
ZW Chen
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Fluid Structure Interaction ◽  
Operating Conditions ◽  
Poisson's Ratio ◽  
Interaction Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Cotton Picker ◽  
Mechanical Performances

A sleeve and its matched spindle are key components of a cotton picker, whose performances affect picking cotton efficiency directly. To enhance the sleeve strength and wear resistance, it is desired to add coatings on the inner surface of the sleeve. In this paper, influences of the coatings on the mechanical performances of the sleeve are investigated with fluid–structure interaction method. Mechanical performances of the sleeve are studied at the varied elastic modulus, Poisson's ratio, and thickness of the coating and different operating conditions. The numerical results show that both the amplitude and position of the von Mises stress and strain of the coated sleeve depend on the varied elastic modulus, Poisson's ratio, and thickness of coating. The coating effect on the sleeve is significant at a big eccentricity ratio or high rotational speed of the spindle.

Validation of Fluid-Structure Interaction Calculations in a Large-Break Loss of Coolant Accident

2008 ◽  
Author(s):  
Antti Timperi ◽  
Timo Pa¨ttikangas ◽  
Ismo Karppinen ◽  
Ville Lestinen ◽  
Jukka Ka¨hko¨nen ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Fluid Structure Interaction ◽  
Acoustic Medium ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Loss Of Coolant Accident ◽  
Phase Calculation ◽  
Loss Of Coolant ◽  
Pipe Break ◽  
Good Agreement

In the hypothetical Large-Break Loss Of Coolant Accident (LBLOCA), rapid depressurization of the reactor primary circuit causes loads on the reactor internals. This paper presents numerical simulations of a HDR experiment, where LBLOCA of a pressurized water reactor due to a sudden pipe break in the primary loop was studied. In the experiment, Fluid-Structure Interaction (FSI) phenomena caused by the flexibility of the core barrel were studied in particular. Star-CD Computational Fluid Dynamics (CFD) code and ABAQUS structural analysis code were used for three-dimensional calculations. The MpCCI code was used for two-way coupling of the CFD and structural analysis codes in order to take FSI into account. Two-way FSI calculation was also performed with ABAQUS only by modeling water as an acoustic medium. Pressure boundary condition at the pipe break was evaluated with the system code APROS as a two-phase calculation. Comparisons with the experiment were made for fluid pressures and break mass flow as well as for structural displacements and strains. Fairly good agreement was found between the experiment and simulation when coupling of the CFD and structural analysis codes was used. For the acoustic calculation, the results showed good agreement in the early phase of the simulation. In the late phase, structural loads were over-predicted by the acoustic calculation due to the effect of bulk flow of water which is not included in the acoustic model.

scholarly journals A GPU-Accelerated Compressible RANS Solver for Fluid-Structure Interaction Simulations in Turbomachinery

2016 ◽  
Author(s):  
L. Mangani ◽  
E. Casartelli ◽  
G. Romanelli ◽  
Magnus Fischer ◽  
A. Gadda ◽  
...  
Keyword(s):  
Computational Efficiency ◽  
Power Efficiency ◽  
Linear Time ◽  
Fluid Structure Interaction ◽  
Operating Conditions ◽  
Structural Deformation ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Non Linear ◽  
The Impact

Computational Fluid Dynamics (CFD) is a fundamental tool for the aerodynamic development in industrial applications. In the usual approach structural deformation due to aerodynamic and thermal loads is often neglected. However, in some cases, where power efficiency is the ultimate goal, an accurate prediction of the structure-flow interaction is essential. This is particularly true for trim and flutter analysis of aircrafts, helicopter and turbomachinery blades. Particularly, turbomachinery trim and flutter predictions still represent a challenge due to phenomena like rotor-stator interaction, separations and shock waves. The usual time-linearised, frequency-domain strategies can be inadequate when this kind of strong non-linear phenomena occur in the flow, making necessary full non-linear time-domain simulations or the harmonic balance technique. Beside flutter, another important aspect, not yet adequately investigated, is the trim analysis, which is fundamental for an accurate steady simulation that aims to consider static blade elasticity for the performance evaluation of turbomachines. Moreover, alongside the obvious contribution given by centrifugal loads to the blade deformation, a not less important source of blade displacement is the thermal effect due to the heat exchanged between the solid and the fluid domains. In particular, for some geometries and operating conditions, thermal effects can be more important than centrifugal effects for the blade deformations. Considering multiple sources of blade deformation (elastic, centrifugal and thermal) in a what is often called “multiphysics” approach is nowadays more and more important, if the goal of the analysis is geometry optimization. To achieve this, next to result’s accuracy also computational efficiency is required, when hundreds of aeroelastic simulations have to be performed in a typical optimization loop. Modern GPUs can be exploited to pursue this goal thanks to their high peak computational power available at relatively low costs and low power consumption with respect to the usual CPUs. In this paper a pioneer work describing the impact of static deformation due to blade elasticity, thermal and centrifugal effects on the performances and power efficiency will be provided. Alongside with accurate results, computational efficiency is taken into account. The purpose of this article is to show the architecture of a GPU-accelerated Fluid-Structure Interaction (FSI) solver for compressible viscous flows. The proposed approach is validated with a typical industrial case, i.e. a turbocharger transonic centrifugal-compressor provided by ABB. The effects of trimmed solutions on the most important integral quantities (i.e. mass flow, characteristic curves, mass-averaged outflow profiles) are investigated and a comparison with pure aerodynamic results is provided. Due to the high blade stiffness and thus the very small displacements obtained with the trim solutions, for the particular case presented in the paper the aeroelastic solutions basically provide nearly the same results as the pure aerodynamic solutions.

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