scholarly journals An experimental investigation of the fluid structure interactions of a single curved nuclear fuel plate in a narrow channel

2017 ◽  
Author(s):  
◽  
Gerhard Schnieders
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Experimental Setup ◽  
Maximum Deflection ◽  
Test Plate ◽  
Fluid Structure ◽  
Research Reactors ◽  
Structure Interaction ◽  
Channel Thickness ◽  
Enriched Uranium

Nuclear research reactors are major scientific tools used by researchers all over the word to produce medical isotopes, irradiated materials, as well as study nuclear processes. Most fuel for research reactors is in the form of plates of uranium clad in aluminum. Forced water flows across the plates for cooling and reaction moderation. The Global Threat Reduction Initiative (GTRI) is an international effort to develop an acceptable low enriched uranium(LEU) fuel to replace the current high enriched uranium (HEU) fuel in research reactors. Because HEU fuel could be used for nuclear weapons, the goal of the GTRI is to prevent proliferation of HEU. The fuel plates and their assemblies must be redesigned using LEU fuel. Also, the LEU assemblies must fit the same profile within the reactors as the HEU assemblies and must provide a similar neutron distribution. The redesigned fuel plates will be thinner and the inter-plate coolant channels will be wider. The fluid structure interaction (FSI) between the fuel plates and coolant needs to be investigated to understand the potential for channel collapse. Channel collapse occurs when plates deflect to the point of touching the neighboring plate significantly cutting off coolant supply. Fluid structure interaction experiments were carried out to validate numerical FSI models that will be used to design structurally stable LEU fuel plates and assemblies. Past analysis has been conducted on flat and involute plates in single and multiple plate assemblies with channels of equal thickness. No previous experiments have been carried out on a curved plate with unequal channel gaps. The experimental setup consists of two stainless steel cylinders with a plate of 0.4604 mm thickness between them to form two flow channels. The inner channel is designed at 2.032 mm thickness and the outer channel thickness is 2.54 mm. The unequal channels are intended to simulate the maximum and minimum allowable channel thickness in the fuel assembly tolerances for the University of Missouri Research Reactor. The test plate is much thinner than the prototype fuel plate design in order to provide measurable deflections for the flow rates that are achievable in the current flow loop. Deflection is measured through plexiglass windows in the outer cylinder using a laser displacement sensor. The flow experiments showed that curved plates deflect into the initially larger channel and have a maximum deflection that increases at a rate greater than linearly with mass flow of the water. The maximum deflection measured was roughly 0.25 mm at a mass flow rate of 2.5 kg/s (average channel velocity of 4.4 m/s). When deflection is plotted against flow rate, a hysteresis is seen between subsequent sets of measurements throughout the experiment. The hysteresis was investigated and attributed to thermal expansion of the test plate due to the pump heating the circulating water. The experimental pressure results matched well with the numerical FSI models of the experimental setup.

scholarly journals A fluid-structure interaction analysis of the human aortic arch under inertial load

2021 ◽  
Author(s):  
Jonathan M Zalger
Keyword(s):  
Mass Flow ◽  
Data Transfer ◽  
Interaction Analysis ◽  
Fluid Structure Interaction ◽  
Longitudinal Axis ◽  
Tissue Response ◽  
Upper Body ◽  
Inertial Load ◽  
Fluid Structure ◽  
Structure Interaction

Presented is an investigation into the use of numerical methods for modelling the effects of inertial load on the human cardiovascular system. An anatomically correct geometry was developed based on three-dimensional computed tomography (CT) data and independent meshes were created for the solid and fluid regimes. These domains were simulated using independent solvers and subsequently coupled using an intermediate data transfer alogrithm. At the inlet of the arch, a pulsatile velocity boundary condition was enforced replicating the cardiac cycle. Time invariant, resistive boundary conditions were used at all outlets and a linear isotropic constitutive model was used for tissue response. Verification was conducted by comparing simulation results at standard earth gravity (9.81 m/s²) with published values for velocity, mass flow rate, deformation, and qualitative flow behaviour. The presented fluid-structure interaction (FSI) model shows strong agreement with accepted normal values. Inertial load was then applied along the longitudinal axis of the arch in multiples of standard gravity to a maximum of 8+Gz. This load increased arch flow velocities, and reduced mass flow in the ascending brachiocephalic and carotid arteries. Blood flow from the arch to the upper body and brain ceased near 8+Gz. Although the presented results are preliminary, the feasibility of such an analysis has been successfully demonstrated.

scholarly journals Experimental Results for the Rotordynamic Characteristics of Leakage Flows in Centrifugal Pumps

1994 ◽  
Vol 116 (1) ◽  
pp. 110-115 ◽  
Author(s):  
A. Guinzburg ◽  
C. E. Brennen ◽  
A. J. Acosta ◽  
T. K. Caughey
Keyword(s):  
Flow Rate ◽  
Tangential Force ◽  
Fluid Structure Interaction ◽  
Centrifugal Pumps ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Leakage Flows ◽  
Clearance Face ◽  
Rotordynamic Forces

In recent years, increasing attention has been given to fluid-structure interaction problems in turbomachines. The present research focuses on just one such fluid-structure interaction problem, namely, the role played by fluid forces in determining the rotordynamic stability and characteristics of a centrifugal pump. The emphasis of this study is to investigate the contributions to the rotordynamic forces from the discharge-to-suction leakage flows between the front shroud of the rotating impeller and the stationary pump casing. An experiment was designed to measure the rotordynamic shroud forces due to simulated leakage flows for different parameters such as flow rate, shroud clearance, face-seal clearance and eccentricity. The data demonstrate substantial rotordynamic effects and a destabilizing tangential force for small positive whirl frequency ratios; this force decreased with increasing flow rate. The rotordynamic forces appear to be inversely proportional to the clearance and change significantly with the flow rate. Two sets of data taken at different eccentricities yielded quite similar nondimensional rotordynamic forces indicating that the experiments lie within the linear regime of eccentricity.

Coupled Calculation on Fluid Structure Interaction in Plate-Type Fuel Element

2018 ◽  
Author(s):  
Yiqi Yu ◽  
Elia Merzari ◽  
Jerome Solberg
Keyword(s):  
Fuel Element ◽  
Fluid Structure Interaction ◽  
Initial Step ◽  
University Of Missouri ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Coupled Calculation ◽  
Enriched Uranium ◽  
Type Fuel ◽  
Plate Type

In nuclear reactors that use plate-type fuel, the fuel plates are thermally managed with coolant flowing through channels between the plates. Depending on the flow rates and sizes of the fluid channels, the hydraulic forces exerted on a plate can be quite large. Currently, there is a worldwide effort to convert research reactors that use highly enriched uranium (HEU) fuel, some of which are plate-type, to low-enriched uranium (LEU). Because of the proposed changes to the fuel structure and thickness, a need exists to characterize the potential for flow-induced deflection of the LEU fuel plates. In this study, as an initial step, calculations of Fluid-Structure Interaction (FSI) for a flat aluminum plate separating two parallel rectangular channels are performed using the commercial code STAR-CCM+ and the integrated multi-physics code SHARP, developed under the Nuclear Energy Advanced Modeling and Simulation program. SHARP contains the high-fidelity single physics packages Diablo and Nek5000, both highly scalable and extensively validated. In this work, verification studies are performed to assess the results from both STAR-CCM+ and SHARP. The predicted deflections of the plate agree well with each other as well as exhibiting good agreement with simulations performed by the University of Missouri utilizing STAR-CCM+ coupled with the commercial structural mechanics code ABAQUS. The study provides a solid basis for FSI modeling capability for plate-type fuel element with SHARP.

scholarly journals MITR Low-Enriched Uranium Conversion Fluid-Structure Interaction Preliminary Design Verification

2021 ◽  
Author(s):  
Guanyi Wang ◽  
Cezary Bojanowski ◽  
Akshay Dave ◽  
David Jaluvka ◽  
Erik Wilson ◽  
...  
Keyword(s):  
Fluid Structure Interaction ◽  
Preliminary Design ◽  
Design Verification ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Enriched Uranium

scholarly journals A Comparison of Physical and Numerical Modeling of Homogenous Isotropic Propeller Blades

2020 ◽  
Vol 8 (1) ◽  
pp. 21 ◽  
Author(s):  
Luca Savio ◽  
Lucia Sileo ◽  
Sigmund Kyrre Ås
Keyword(s):  
Numerical Modeling ◽  
Open Water ◽  
Computational Approach ◽  
Experimental Setup ◽  
Fluid Structure ◽  
Towing Tank ◽  
Design Procedures ◽  
Structure Interaction ◽  
Marine Propellers ◽  
Propeller Blades

Results of the fluid-structure co-simulations that were carried out as part of the FleksProp project are presented. The FleksProp project aims to establish better design procedures that take into account the hydroelastic behavior of marine propellers and thrusters. Part of the project is devoted to establishing good validation cases for fluid-structure interaction (FSI) simulations. More specifically, this paper describes the comparison of the numerical computations carried out on three propeller designs that were produced in both a metal and resin variant. The metal version could practically be considered rigid in model scale, while the resin variant would show measurable deformations. Both variants were then tested in open water condition at SINTEF Ocean’s towing tank. The tests were carried out at different propeller rotational speeds, advance coefficients, and pitch settings. The computations were carried out using the commercial software STAR-CCM+ and Abaqus. This paper describes briefly the experimental setup and focuses on the numerical setup and the discussion of the results. The simulations agreed well with the experiments; hence, the computational approach has been validated.

Factors of Influence on the Leakage of Brush Seals

2020 ◽  
Author(s):  
Alexander Fuchs ◽  
Johann Göttler ◽  
Oskar J. Haidn
Keyword(s):  
Fluid Dynamics ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Interaction Model ◽  
Structure Interaction ◽  
Preliminary Results ◽  
Mechanics Model ◽  
Factors Of Influence ◽  
Brush Seals

Abstract Based on previous research from the authors a modeling approach for brush seals is developed further. Each individual bristle is reproduced in both the fluid dynamics and the structural mechanics model. An investigation regarding the influence of the free bristle height and the sealing gap on the leakage mass flow rate is carried out. Results are compared to experimental and literature data. Furthermore, preliminary results of the segregated fluid-structure interaction model are presented briefly, and matched to literature data.

scholarly journals Development and experimental benchmarking of numeric fluid structure interaction models for research reactor fuel analysis

2015 ◽  
Author(s):  
◽  
John Charles Kennedy
Keyword(s):  
High Velocity ◽  
Plate Thickness ◽  
Fluid Structure Interaction ◽  
Quality Data ◽  
Flow Rates ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Manufacturing Tolerances ◽  
Enriched Uranium ◽  
Plate Deflection

As part of the Global Threat Reduction Initiative (GTRI) reactor conversion program, five U.S. High Performance Research Reactors (HPRRs) are currently studying a novel Low Enriched Uranium (LEU) foil based fuel to replace their current High Enriched Uranium (HEU) dispersion fuel. The proposed fuel uses a monolithic U-10Mo foil meat clad in aluminum, whereas the current HEU fuel meat is comprised of Uranium dispersed in an aluminum matrix, before being clad in aluminum. Along with a change in the physical structure of the fuel, the fuel plate thickness has been significantly decreased. Given that these fuel plates are subject to high velocity coolant flow, these changes in the plate design have led to a need to characterize the structural response of the plates in presence of high velocity flow. The proposed method for completing this analysis is to use novel fluid-structure interaction (FSI) simulations. These simulations are carried out using commercial CFD and FEA solvers Star-CCM+ and Abaqus, and iteratively coupling their solutions together at the interface between the plate and the fluid. Given the unique nature of these simulations, it is necessary to first benchmark and qualify the codes for this analysis. To generate benchmark quality data, a flow loop and test section have been constructed for studying plate deflection and channel pressure drop under a variety of fluid flow conditions. Similar experimental analysis which considered equally sized fluid channels has been studied by a number of individuals in the past. The work presented here differs however, by intentionally offsetting the plate and creating fluid channels of different thickness. This offset effectively simulates manufacturing tolerances of a real fuel assembly. A method for generating 'As-Built' numeric models of the experiment geometry is presented. These As-Built numeric models have been shown to dramatically improve matching between experiment and numeric solutions, particularly at low- to mid-range flow rates. At higher flow rates, the experiment exhibited a dynamic 'snap' behavior that could not be replicated numerically. Additional interrogation of the boundary conditions revealed a possible explanation for this snap, however numeric methods do not yet exist for recreating this behavior. In earlier works which considered equally sized channels, plate deflection was not examined in detail and was found to be largely unpredictable and reliant upon the manufacturing tolerances of the experiment. In the numeric and experimental work presented here, plate deflection behavior at low to mid-range flow rates is qualitatively consistent with theoretical expectations.

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