scholarly journals Investigations On Flow And Flow-Induced Vibration Of Candu Fuel Bundles

2021 ◽  
Author(s):  
Alokendu Bhattacharya
Keyword(s):  
High Performance ◽  
Nuclear Reactor ◽  
Angular Position ◽  
Three Dimensional ◽  
Power Spectra ◽  
Wide Band ◽  
Major Step ◽  
Processing Scheme ◽  
Fuel Channel ◽  
Fuel Bundle

Excitations induced by three-dimensional unsteady flows of ordinary water coolant through a string of CANDU fuel bundles in a fuel channel are investigated in this thesis. Several comprehensive computational fluid dynamics (CFD) models are developed and solved by means of large eddy simulation (LES), high performance computers and parallel processing scheme. The 12-bundle flow model is the first ever developed concerning flow in a very complex CANDU fuel channel. The lateral fluid flow and flow-induced excitations on every fuel bundle are obtained and analyzed for various combinations of bundle angular positions. The coherent nature of the flow through the multiple bundles inside the fuel channel exhibiting fluid excitations of frequencies spreaded over a wide band in the power spectra is a source of bundle lateral vibration. The flow features of different bundle regime are correlated both in time and frequency domain and they are sensitive to the bundle-to-bundle angular position. This finding directs that, to study the flow and flow-induced excitations and vibrations of a bundle string, it is necessary to include all bundles for fluid-structure interactions. Results from the computational model reveal that the misaligned interface changes the flow pattern in the fuel channel. The mean lateral fluid forces increase by an order of magnitude and their RMS values raise about 3 to 4 times at some configurations compared to fully aligned situation. Experiments are also performed using the simulated CANDU bundles in an out-reactor setup to verify the computational results. An analysis of a complete fuel channel of a nuclear reactor using LES is at the forefront of current research worldwide and this study is a major step forward towards understanding and unfolding the fuel bundle vibration phenomenon.

Investigations On Flow And Flow-Induced Vibration Of Candu Fuel Bundles

2021 ◽  
Author(s):  
Alokendu Bhattacharya
Keyword(s):  
High Performance ◽  
Nuclear Reactor ◽  
Angular Position ◽  
Three Dimensional ◽  
Power Spectra ◽  
Wide Band ◽  
Major Step ◽  
Processing Scheme ◽  
Fuel Channel ◽  
Fuel Bundle

Excitations induced by three-dimensional unsteady flows of ordinary water coolant through a string of CANDU fuel bundles in a fuel channel are investigated in this thesis. Several comprehensive computational fluid dynamics (CFD) models are developed and solved by means of large eddy simulation (LES), high performance computers and parallel processing scheme. The 12-bundle flow model is the first ever developed concerning flow in a very complex CANDU fuel channel. The lateral fluid flow and flow-induced excitations on every fuel bundle are obtained and analyzed for various combinations of bundle angular positions. The coherent nature of the flow through the multiple bundles inside the fuel channel exhibiting fluid excitations of frequencies spreaded over a wide band in the power spectra is a source of bundle lateral vibration. The flow features of different bundle regime are correlated both in time and frequency domain and they are sensitive to the bundle-to-bundle angular position. This finding directs that, to study the flow and flow-induced excitations and vibrations of a bundle string, it is necessary to include all bundles for fluid-structure interactions. Results from the computational model reveal that the misaligned interface changes the flow pattern in the fuel channel. The mean lateral fluid forces increase by an order of magnitude and their RMS values raise about 3 to 4 times at some configurations compared to fully aligned situation. Experiments are also performed using the simulated CANDU bundles in an out-reactor setup to verify the computational results. An analysis of a complete fuel channel of a nuclear reactor using LES is at the forefront of current research worldwide and this study is a major step forward towards understanding and unfolding the fuel bundle vibration phenomenon.

scholarly journals Numerical and experimental investigations on vibration of simulated CANDU fuel bundles subjected to turbulent fluid flow

2021 ◽  
Author(s):  
Xuan Zhang
Keyword(s):  
Numerical Simulations ◽  
Nuclear Reactor ◽  
Plate Theory ◽  
Three Dimensional ◽  
Element Model ◽  
Experimental Investigations ◽  
Flow Induced Vibration ◽  
Flow Measurements ◽  
Eddy Simulation ◽  
Fuel Bundle

Vibration of simulated CANDU fuel bundles induced by coolant flow is investigated in this thesis through experiments and numerical simulations. Two simulated bundles and a hydraulic loop are built to mimic the situation of the fuel bundles located at the inlet of a fuel channel in a CANDU nuclear reactor. Fuel bundle vibration mechanism is investigated through experiments and numerical simulations. The three-dimensional turbulent flow that passes through the simulated bundles is modeled using the large eddy simulation (LES) and solved with parallel processing. The local cross flows induced by the presence of endplates at the inlet location and bundle interface location are investigated. The fluid forces are obtained as excitations for the fuel bundle vibration analysis. A finite element model of the fuel bundles is developed with the endplates modeled using the 3rd order thick plate theory. The response of the inlet fuel bundle to the fluid excitations is solved in the time and the frequency domain. The added mass and the fluid damping are approximated with the theory on the flow-induced vibration of slender bodies in a parallel flow. Measurements are obtained and used to validate the numerical prediction under various operating flow conditions.

scholarly journals Numerical and experimental investigations on vibration of simulated CANDU fuel bundles subjected to turbulent fluid flow

2021 ◽  
Author(s):  
Xuan Zhang
Keyword(s):  
Numerical Simulations ◽  
Nuclear Reactor ◽  
Plate Theory ◽  
Three Dimensional ◽  
Element Model ◽  
Experimental Investigations ◽  
Flow Induced Vibration ◽  
Flow Measurements ◽  
Eddy Simulation ◽  
Fuel Bundle

Vibration of simulated CANDU fuel bundles induced by coolant flow is investigated in this thesis through experiments and numerical simulations. Two simulated bundles and a hydraulic loop are built to mimic the situation of the fuel bundles located at the inlet of a fuel channel in a CANDU nuclear reactor. Fuel bundle vibration mechanism is investigated through experiments and numerical simulations. The three-dimensional turbulent flow that passes through the simulated bundles is modeled using the large eddy simulation (LES) and solved with parallel processing. The local cross flows induced by the presence of endplates at the inlet location and bundle interface location are investigated. The fluid forces are obtained as excitations for the fuel bundle vibration analysis. A finite element model of the fuel bundles is developed with the endplates modeled using the 3rd order thick plate theory. The response of the inlet fuel bundle to the fluid excitations is solved in the time and the frequency domain. The added mass and the fluid damping are approximated with the theory on the flow-induced vibration of slender bodies in a parallel flow. Measurements are obtained and used to validate the numerical prediction under various operating flow conditions.

Wireless communicating nodes at 60 GHz integrated on flexible substrate for short-distance instrumentation in aeronautics and space

2011 ◽  
Vol 4 (1) ◽  
pp. 109-117 ◽  
Author(s):  
Mohamed Mehdi Jatlaoui ◽  
Daniela Dragomirescu ◽  
Mariano Ercoli ◽  
Michael Krämer ◽  
Samuel Charlot ◽  
...  
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Flexible Substrate ◽  
Three Dimensional ◽  
Wide Band ◽  
Cmos Technology ◽  
Electrical Contacts ◽  
Planar Antenna ◽  
60 Ghz ◽  
Polyimide Substrate

This paper presents the research done at LAAS-CNRS and in the context of “NANOCOMM” project. This project aims to demonstrate the potential of nanotechnology for the development of reconfigurable, ultra-sensitive, low consumption, and easy installation sensor networks with high performance in terms of reliability in line with the requirements of aeronautics and space. Each node of the sensor network is composed of nano-sensors, transceiver, and planar antenna. In this project, three-dimensional (3D) heterogeneous integration of these different components, on flexible polyimide substrate, is planned. Two types of sensors are selected for this project: strain gauges are used for the structure health monitoring (SHM) application and electrochemical cells are used to demonstrate the ability to detect frost phenomenon. After processing, sensors data are processed and transmitted to the reader unit using an ultra-wide band (UWB) transceiver. (digital baseband and radiofrequency (RF) head). The design and implementation of reconfigurable wireless communication architectures are provided according to the application requirements using nanoscale 65 nm CMOS technology. It is proposed to integrate on flexible substrate the transceiver using the flip-chip technique. A 60 GHz planar antenna is connected to the transceiver for the wireless data transmission. This paper is focused on the 3D integration techniques and the technological process used for the realization of such communicating nano-objects on polyimide substrate. The first assembly tests were carried out. Tests of interconnections quality and electrical contacts (Daisy Chain, calibration kit, etc.) were also performed with good results. A bumps contact resistance of 15 mΩ is measured.

Improved 3-D reconstruction using stereo computer graphics and multiple tilt EM images

1995 ◽  
Vol 53 ◽  
pp. 630-631
Author(s):  
Lee D. Peachey ◽  
Lou Fodor ◽  
John C. Haselgrove ◽  
Stanley M. Dunn ◽  
Junqing Huang
Keyword(s):  
Computer Graphics ◽  
High Performance ◽  
Transverse Section ◽  
Three Dimensional ◽  
Stereo Pair ◽  
3D Reconstructions ◽  
Video Cameras ◽  
Biological Objects ◽  
Microscope Images ◽  
High Performance Computer

Stereo pairs of electron microscope images provide valuable visual impressions of the three-dimensional nature of specimens, including biological objects. Beyond this one seeks quantitatively accurate models and measurements of the three dimensional positions and sizes of structures in the specimen. In our laboratory, we have sought to combine high resolution video cameras with high performance computer graphics systems to improve both the ease of building 3D reconstructions and the accuracy of 3D measurements, by using multiple tilt images of the same specimen tilted over a wider range of angles than can be viewed stereoscopically. Ultimately we also wish to automate the reconstruction and measurement process, and have initiated work in that direction.Figure 1 is a stereo pair of 400 kV images from a 1 micrometer thick transverse section of frog skeletal muscle stained with the Golgi stain. This stain selectively increases the density of the transverse tubular network in these muscle cells, and it is this network that we reconstruct in this example.

Image formation analysis of thick biological specimens using three-dimensional power-spectra of through focus series

1994 ◽  
Vol 52 ◽  
pp. 124-125
Author(s):  
Karen F. Han
Keyword(s):  
Inelastic Scattering ◽  
Imaging Techniques ◽  
Mass Density ◽  
Relative Proportion ◽  
Three Dimensional ◽  
Power Spectra ◽  
Image Formation ◽  
Energy Filtering ◽  
Ewald Sphere ◽  
Nonlinear Imaging

The primary focus in our laboratory is the study of higher order chromatin structure using three dimensional electron microscope tomography. Three dimensional tomography involves the deconstruction of an object by combining multiple projection views of the object at different tilt angles, image intensities are not always accurate representations of the projected object mass density, due to the effects of electron-specimen interactions and microscope lens aberrations. Therefore, an understanding of the mechanism of image formation is important for interpreting the images. The image formation for thick biological specimens has been analyzed by using both energy filtering and Ewald sphere constructions. Surprisingly, there is a significant amount of coherent transfer for our thick specimens. The relative amount of coherent transfer is correlated with the relative proportion of elastically scattered electrons using electron energy loss spectoscopy and imaging techniques.Electron-specimen interactions include single and multiple, elastic and inelastic scattering. Multiple and inelastic scattering events give rise to nonlinear imaging effects which complicates the interpretation of collected images.

Rationally Designed Three-Dimensional Porous Nico 2n@C Reticular Structure for High-Performance Li-Ion Batteries

2020 ◽  
Author(s):  
Peiyao Wang ◽  
Bangchuan Zhao ◽  
Jin Bai ◽  
Kunzhen Li ◽  
Hongyang Ma ◽  
...  
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Li Ion Batteries ◽  
Reticular Structure ◽  
Li Ion

CALCULATION OF THE DEPENDENCE OF THE DISTANCE TO THE LOCATED OBJECT FROM THE CORNER POSITION OF THE VEHICLE LINE

2018 ◽  
pp. 14-18
Author(s):  
V. V. Artyushenko ◽  
A. V. Nikulin
Keyword(s):  
Real Time ◽  
Statistical Physics ◽  
Angular Position ◽  
Three Dimensional ◽  
Line Of Sight ◽  
Two Dimensional ◽  
Radar Station ◽  
Flight Mode ◽  
Vector Algebra ◽  
Analytical Expressions

To simulate echoes from the earth’s surface in the low flight mode, it is necessary to reproduce reliably the delayed reflected sounding signal of the radar in real time. For this, it is necessary to be able to calculate accurately and quickly the dependence of the distance to the object being measured from the angular position of the line of sight of the radar station. Obviously, the simplest expressions for calculating the range can be obtained for a segment or a plane. In the text of the article, analytical expressions for the calculation of range for two-dimensional and three-dimensional cases are obtained. Methods of statistical physics, vector algebra, and the theory of the radar of extended objects were used. Since the calculation of the dependence of the range of the object to the target from the angular position of the line of sight is carried out on the analytical expressions found in the paper, the result obtained is accurate, and due to the relative simplicity of the expressions obtained, the calculation does not require much time.

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