Thermal-Structural Analysis of the Super-Heater Tubes of a Unit of 158 MW

2011 ◽  
Author(s):  
J. A. Alfaro-Ayala ◽  
A. Gallegos-Mun˜oz ◽  
A. Olivares-Arriaga ◽  
A. Zaleta-Aguilar ◽  
J. J. Vazquez Martinez
Keyword(s):  
Structural Analysis ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Internal Flow ◽  
Three Dimensional Model ◽  
Super Heater ◽  
Structural Stresses ◽  
Thermal Dilatation ◽  
Rigid Zones ◽  
Selection Of

The thermal-structural analysis of the super-heater tubes for a 158 MW unit, applying FLUENT® (CFD) and ANSYS® (FEA), is presented. The analysis includes the spacers (union piece between tubes), welding and tubes. The failures of these elements are related with the operation of the unit and the selection of the weld and materials involved in the affected zone. The distribution of temperature in each metal depends of the thermal conductivity and coefficient of thermal expansion, provoking stress concentration in the rigid zones. The CFD study considers a three-dimensional model where the conjugate heat transfer, including internal flow (steam) and external flow (gases), was analyzed to full load of the unit in steady state. In the FEA study, the thermal-structural stresses were analyzed considering the temperature distribution obtained from the CFD study. The results obtained show that the spacer is of greater temperature than the tubes, provoking gradients of temperature through tube walls, spacers and welds. The highest stress located on the interior tube wall (on the direction of plane where the spacer is welded) is attributed to the different thermal dilatation and pressure expansion of the tube, spacer and weld. The study includes the analysis of some geometries of the union piece (spacer) to release the thermal-structural stresses.

Stable Platform Based on Workbench Vehicle Structure Analysis

2013 ◽  
Vol 477-478 ◽  
pp. 132-134
Author(s):  
Jin Xia Liu ◽  
Chong Chen ◽  
Liang Wang ◽  
Cong Zhang
Keyword(s):  
Numerical Analysis ◽  
Structural Analysis ◽  
Structure Analysis ◽  
Tilt Angle ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Vehicle Structure ◽  
Platform Tilt

This paper has conducted a structural analysis by workbench after establishing a stable platform for automotive three-dimensional model, primarily concerning whether the platform can provide a benchmark to meet the requirements of equipment, including the numerical analysis of whether the platform tilt angle under load can achieve the requirements as well as the scheme of improvement direction of the structure.

Numerical simulation of three-dimensional airflow in a novel dual-feed rotor spinning box

2016 ◽  
Vol 88 (3) ◽  
pp. 237-253 ◽  
Author(s):  
Nicholus Tayari Akankwasa ◽  
Huiting Lin ◽  
Yuze Zhang ◽  
Jun Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Internal Flow ◽  
Velocity Variation ◽  
Positive Pressure ◽  
Three Dimensional Model ◽  
Air Velocity ◽  
Rotor Spinning ◽  
Pressure Profiles

In order to regulate turbulence strength and determine airflow characteristics in a new dual-feed rotor spinning unit, the internal flow field is investigated. A computational fluid dynamics technique is employed to numerically study the three-dimensional model of the internal airflow in the new design. The effects of air velocity variation on turbulence strength, negative pressure, Re, and wall pressure distribution are investigated based on simulation data and previous studies. The results show that the turbulence strength and Re increased with increase in inlet air velocity. Pressure profiles inside the rotor varied significantly with positive pressure observed at the channel exits. Minimal inlet velocity maintains the flow field in the rotor interior below 100 m/s, which gives the ideal turbulence required to minimize yarn quality deterioration. The dual-feed rotor spinning unit showed more orderly streamline patterns with fewer vortices compared to the conventional one. The numerical simulation can provide insights on airflow studies and some guidelines for future prototyping and experiments to further improve the new design.

scholarly journals Structural analysis of clastic dikes based on Structure from Motion/Multi-View Stereo

2018 ◽  
Author(s):  
Carlos H Grohmann ◽  
Camila D Viana ◽  
Mariana TS Busarello ◽  
Guilherme PB Garcia
Keyword(s):  
Structural Analysis ◽  
Structure From Motion ◽  
Low Cost ◽  
Three Dimensional ◽  
Fine Sand ◽  
Bundle Adjustment ◽  
Three Dimensional Model ◽  
Focal Distance ◽  
Camera Orientation ◽  
Camera Position

This work presents the development of a three-dimensional model of an outcrop of the Corumbataí Formation using Structure from Motion and Multi-View Stereo (SfM-MVS) techniques in order to provide a structural analysis of clastic dikes cutting through siltstone layers. Composed mainly of fine sand and silt, these dikes are formed by sand intrusions when a wet sandy layer is affected by earthquakes of at least 6.5 magnitude, being used as a record of such events.While traditional photogrammetry requires the user to input a series of parameters related to the camera orientation and its characteristics (such as focal distance), in SfM-MVS the scene geometry, camera position and orientations are automatically determined by a bundle adjustment, an iterative procedure based on a set of overlapping images. It is considered a low-cost technique in both hardware and software, also being able to provide point density and accuracy on par to the ones obtained with terrestrial laser scanner.The results acquired on this research have a good agreement with previous works, yielding a NNW main orientation for the dikes measured in the field and on the 3D model. The development of this work showed that SfM-MVS use and practice on geosciences still needs more studies on the optimization of the involved parameters (such as camera orientation, image overlap and angle of illumination), which, when accomplished, will result in less processing time and more accurate models.

scholarly journals First person – Roberta Azzarelli

Biology Open ◽  
2021 ◽  
Vol 10 (2) ◽  
Keyword(s):  
Developmental Biology ◽  
Stem Cell ◽  
Three Dimensional ◽  
Early Career ◽  
First Person ◽  
Tumor Stem Cells ◽  
Three Dimensional Model ◽  
University Of Cambridge ◽  
Research Associate ◽  
Selection Of

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping early-career researchers promote themselves alongside their papers. Roberta Azzarelli is first author on ‘Three-dimensional model of glioblastoma by co-culturing tumor stem cells with human brain organoids’, published in BiO. Roberta conducted the research described in this article while a Rita Levi Montalcini fellow in Roberta Azzarelli's lab at Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Italy. She is now a research associate in the lab of Anna Philpott at the Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, UK, investigating how stem cell and developmental biology can help tackle cancer.

Numerical Analysis of Crack Propagation in Silicon Nitride

2011 ◽  
Vol 490 ◽  
pp. 216-225 ◽  
Author(s):  
Waldemar Karaszewski
Keyword(s):  
Numerical Analysis ◽  
Crack Propagation ◽  
Coefficient Of Thermal Expansion ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Contact Fatigue ◽  
High Hardness ◽  
Rolling Contact ◽  
Three Dimensional Model ◽  
Ring Crack

The properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculation are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack front are analyzed using a three-dimensional boundary element model. The numerical analysis is verified by experimental studies.

scholarly journals Characterization of Residual Stresses in Veneering Ceramics for Prostheses with Zirconia Framework

2018 ◽  
Vol 29 (4) ◽  
pp. 347-353 ◽  
Author(s):  
Vagner Flávio Reginato ◽  
Daniel Takanori Kemmoku ◽  
Ricardo Armini Caldas¹ ◽  
Ataís Bacchi³ ◽  
Carmem Silvia Pfeifer ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
The Finite Element Method ◽  
Three Dimensional Model ◽  
Linear Contraction ◽  
Cte Mismatch ◽  
Fixed Prosthesis

Abstract The aim of this study was to evaluate the influence of the coefficient of thermal expansion (CTE or α) and glass transition temperature (Tg) of three veneering ceramics used with zirconia frameworks of full-arch fixed prostheses. The generation of residual stresses and linear contraction after the simulation of the cooling process and mechanical loading were measured. The analysis was based on the finite element method in three-dimensional model of a maxillary full-arch fixed prosthesis with zirconia framework (e.max ZirCAD) and veneer by felsdpathic ceramics (GEC - IPS e.max Ceram, GVM - Vita VM9 and GLC - Lava Ceram). The linear contraction simulation was performed by cooling the structures from the Tg of each veneer ceramic at room temperature (25°C). A loading of 100 N on the occlusal region of the first molar was performed. The magnitude of the maximum principal stress (smax) and linear contraction were evaluated. The levels of CTE mismatch between veneering ceramics and framework showed no relevant influence on smax and linear contraction. The Tg values of the veneer ceramic showed to be directly proportional to amount of smax and linear contraction. The GEC presented the highest values of smax and linear contraction. The GVM and GLC did not present significant differences between them. In conclusion, GVM was similar to GLC, while GEC presented differences in relation to other veneer ceramics in terms of residual stress and linear contraction.

The Modeling and Flow Simulation of 40BZ6-15 Centrifugal Pump

2011 ◽  
Vol 317-319 ◽  
pp. 789-793
Author(s):  
Xiao Feng Shang ◽  
Liang Tong ◽  
Zhi Jian Wang
Keyword(s):  
Velocity Field ◽  
Centrifugal Pump ◽  
Pressure Field ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Internal Flow ◽  
Navier Stokes ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Navier Stokes Equation

The three-Dimensional model of 40BZ6-15 centrifugal pump is built by the Solidworks software. This paper employs three-D Navier-Stokes equation and standard equation, and uses MRF and STMPLE algorithm to simulate the internal flowing of the 40BZ6 centrifugal pump. The velocity field and pressure field are gained. Through a further analysis, the rule of the internal flow of the centrifugal pump is unveiled, and then the simulative results are compared with the experimental ones, which can provide the base for the further improvement of the centrifugal pump.

Analysis of Ceramic Elements with Ring-Crack Defects in Lubricated Rolling Contact

2016 ◽  
Vol 250 ◽  
pp. 43-49 ◽  
Author(s):  
Waldemar Karaszewski
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Rolling Contact Fatigue ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Contact Fatigue ◽  
High Hardness ◽  
Rolling Contact ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Ring Crack

The properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. Surface ring cracks on lubricating rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations are based on a three-dimensional model of the ring crack. The stress intensity factors along crack front are analyzed using a finite element analysis. The numerical analysis is verified by experimental studies.

scholarly journals LASER-SCANNER SURVEY OF STRUCTURAL DISORDERS: AN INSTRUMENT TO INSPECT THE HISTORY OF PARMA CATHEDRAL’S CENTRAL NAVE

2017 ◽  
Vol XLII-5/W1 ◽  
pp. 167-174 ◽  
Author(s):  
N. Bruno ◽  
E. Coïsson ◽  
M. Cotti
Keyword(s):  
Structural Analysis ◽  
Distinct Element ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
First Case ◽  
Transverse Arch ◽  
Structural Disorders ◽  
The One

This paper presents the use of laser scanner derived data for the study of the structural disorders in the central nave of the Parma Cathedral. An accurate three-dimensional model of the entire nave was realized to investigate deformations, in order to reconstruct the original conformation and the subsequent evolutions, also in comparison with previous surveys. Specifically, for the analysis presented in the paper, seven scans were performed, one for each bay: the results allowed to compare the deformations on the seven vaults, on the transverse and diagonal arches, giving first hints on the possible differences in the behaviour between the different elements. The measures on the levels of floor and pillars bases were analysed in a historical monitoring approach, in order to retrace the evolution of the differential settlements in time, since the construction of the building. Moreover, a structural analysis has been carried out on one transverse arch with distinct element analysis, with two different approaches. In one case, the structure was inserted exactly as surveyed, and then subjected to the actions. In the second case, the original geometry, before the deformation, was retraced through a parametric approach and the structural analysis basically started at the beginning of the building’s life, thus trying to model not only the present structural situation, but also the path which led to the current deformation. The results were particularly meaningful as they showed that in the first case, disregarding the footsteps of history, the stress pattern inside the masonry was very different from the one obtained in the second case, which is more likely to represent the present conditions.

scholarly journals Structural analysis of clastic dikes based on Structure from Motion/Multi-View Stereo

2018 ◽  
Author(s):  
Carlos H Grohmann ◽  
Camila D Viana ◽  
Mariana TS Busarello ◽  
Guilherme PB Garcia
Keyword(s):  
Structural Analysis ◽  
Structure From Motion ◽  
Low Cost ◽  
Three Dimensional ◽  
Fine Sand ◽  
Bundle Adjustment ◽  
Three Dimensional Model ◽  
Focal Distance ◽  
Camera Orientation ◽  
Camera Position

This work presents the development of a three-dimensional model of an outcrop of the Corumbataí Formation using Structure from Motion and Multi-View Stereo (SfM-MVS) techniques in order to provide a structural analysis of clastic dikes cutting through siltstone layers. Composed mainly of fine sand and silt, these dikes are formed by sand intrusions when a wet sandy layer is affected by earthquakes of at least 6.5 magnitude, being used as a record of such events.While traditional photogrammetry requires the user to input a series of parameters related to the camera orientation and its characteristics (such as focal distance), in SfM-MVS the scene geometry, camera position and orientations are automatically determined by a bundle adjustment, an iterative procedure based on a set of overlapping images. It is considered a low-cost technique in both hardware and software, also being able to provide point density and accuracy on par to the ones obtained with terrestrial laser scanner.The results acquired on this research have a good agreement with previous works, yielding a NNW main orientation for the dikes measured in the field and on the 3D model. The development of this work showed that SfM-MVS use and practice on geosciences still needs more studies on the optimization of the involved parameters (such as camera orientation, image overlap and angle of illumination), which, when accomplished, will result in less processing time and more accurate models.

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