The Proposal of Wall Thickness Management Criteria of T-Pipes

2012 ◽  
Author(s):  
Kiyoharu Tsunokawa ◽  
Taku Ohira ◽  
Naoki Miura ◽  
Yasumi Kitajima ◽  
Daisuke Yoshimura
Keyword(s):  
Numerical Simulation ◽  
Wall Thickness ◽  
Parametric Study ◽  
The Other ◽  
Wall Thinning ◽  
Study Results ◽  
Simulation Results ◽  
Design Construction

Although the reinforcement for openings is checked in accordance with design / construction standard when thinning was observed in T-pipes, this evaluation becomes too conservative or requires much time and effort. This paper describes additional parametric study results and proposes a guideline for thickness management of wall thinning T-pipes. On the other papers related to this project, the experiment and numerical simulation results are reported. This paper referred these results and performed further investigation.

Proposal of a Guideline for Thickness Management of Wall Thinning T-Joints

2012 ◽  
Author(s):  
Mayumi Ochi ◽  
Katsuhiko Yamakami ◽  
Yoshinobu Hamaguchi ◽  
Katsumasa Miyazaki ◽  
Keita Naito ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Japan Society ◽  
Minimum Thickness ◽  
T Joints ◽  
Wall Thinning ◽  
Study Results ◽  
Simulation Results ◽  
Design Pressure ◽  
Design Construction

Although the required minimum thickness (tsr) of T-joints (tees) of class 2, 3 and lower classes of nuclear power plants in Japan is calculated from the design pressure and temperature for design, there are neither any rules nor standards for thickness management of wall thinning T-joints for facilities maintenance. This paper describes additional parametric study results and proposes a guideline for thickness management of wall thinning T-joints. In other papers related to this project, the experiment and numerical simulation results are reported. This paper refers to these results and performs further investigation under the consideration of JSME (The Japan Society of Mechanical Engineers) design, construction and maintenance codes and standards.

Modeling Recrystallization for 3D Multi-Pass Forming Processes

2007 ◽  
Vol 558-559 ◽  
pp. 1201-1206 ◽  
Author(s):  
Mihaela Teodorescu ◽  
Patrice Lasne ◽  
Roland E. Logé
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Present Model ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
The Other ◽  
Finite Element Code ◽  
3D Numerical Simulation ◽  
Fraction Distribution ◽  
Simulation Results

The present work concerns the simulation of metallurgical evolutions in 3D multi-pass forming processes. In this context, the analyzed problem is twofold. One point refers to the management of the microstructure evolution during each pass or each inter-pass period and the other point concerns the management of the multi-pass aspects (different grain categories, data structure). In this framework, a model is developed and deals with both aspects. The model considers the microstructure as a composite made of a given (discretized) number of phases which have their own specific properties. The grain size distribution and the recrystallized volume fraction distribution of the different phases evolve continuously during a pass or inter-pass period. With this approach it is possible to deal with the heterogeneity of the microstructure and its evolution in multi-pass conditions. Both dynamic and static recrystallization phenomena are taken into account, with typical Avrami-type equations. The present model is implemented in the Finite Element code FORGE2005®. 3D numerical simulation results for a multi-pass process are presented.

Study on Numerical Simulation of Fire and Evacuation for a Supermarket

2015 ◽  
Vol 744-746 ◽  
pp. 1736-1740 ◽  
Author(s):  
Si Hui Dong ◽  
Min Li ◽  
Yu Han Lin
Keyword(s):  
Numerical Simulation ◽  
Physical Model ◽  
Development Process ◽  
Fire Danger ◽  
Actual Situation ◽  
Study Results ◽  
Simulation Results ◽  
Fire Scene ◽  
Safety Evacuation

3D physical model of a supermarket was constructed with Pyrosim software, and the fire scene was set according to the actual situation. The fire development process and personnel evacuation process were simulated with FDS. The fire danger time of the fire scene was analyzed according to the smoke temperature and visibility of different time. The personnel evacuation process to the supermarket was simulated with the evacuation software Evac, and the required safety egress time was calculated. By comparing the fire danger time and the required safety egress time, the conclusion was drawn that the supermarket can not meet the requirement for safety evacuation. After changing the conditions for safety evacuation, the required safety egress time was simulated again. And the simulation results showed that the changed evaluation conditions can meet the requirement for safety evacuation. The study results provide a basis to improve the safety evacuation conditions of the supermarket.

The Numerical Simulation of Air Bulge Forming of Profiled Can

2010 ◽  
Vol 97-101 ◽  
pp. 2774-2778
Author(s):  
Jie Jin ◽  
Xin He
Keyword(s):  
Numerical Simulation ◽  
Parameter Estimation ◽  
Friction Coefficient ◽  
Process Parameters ◽  
Wall Thickness ◽  
Process Parameter ◽  
The Other ◽  
Technological Parameters ◽  
Forming Process ◽  
Inner Pressure

Air bulge forming is a forming process where an inner pressure deforms the material to the shape of a die cavity. The main concerns about such a process of profiled cans are to avoid wall thickness reduction, wrinkling and bursting. The success of this process strongly depends on the choice of process parameters, i.e. the properties of material, thickness and inner pressure. By transforming the problem into a deformation controlled rather than a force controlled process, the results from the process parameter estimation become more reliable but on the other hand less intuitive. In this context, the influence of materials, friction coefficient, transitional fillet radius, thickness and bulging load are studied and some suited technological parameters and forming rules are obtained. The most important point is that the simulation and results of experiments are probably consistent.

Numerical Simulation of Different Coal Combustion in Two Tiny-Oil Ignition Burners With Oxygen-Enriched

2012 ◽  
Author(s):  
Yongsheng Zhang ◽  
Haisu Wu ◽  
Xueqi Liu ◽  
Chenn Qian Zhou ◽  
Zhongguang Fu
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Coal Combustion ◽  
Bituminous Coal ◽  
The Other ◽  
Temperature Zone ◽  
Heating Value ◽  
Oxygen Burner ◽  
High Volatility ◽  
Simulation Results

Two tiny-oil ignition combustion burners with oxygen-enriched were studied in this paper. One is adding oxygen directly into primary air, and the other is adding oxygen by extra adding-oxygen tube. The bituminous coal, the lignite, and the meager coal, are simulated in these burners. By comparing the two different combustion characteristics, the simulation results show that, for bituminous coal, the high temperature zone congregates in the first directly added oxygen burner, while, for the meager coal, it is difficult to burn in the first directly added oxygen burner. As to the lignite, because of its characteristics of high volatility and low heating value, the first directly added oxygen burner provide oxygen timely for its high volatile, its flame combust more quickly and directly.

Origin of Leakage Currents in ZnO Based Varistor Ceramics with Al(NO3)3 Dopant

2010 ◽  
Vol 434-435 ◽  
pp. 386-388 ◽  
Author(s):  
Jun Hu ◽  
Wang Chen Long ◽  
Jin Liang He ◽  
Jun Liu ◽  
Feng Chao Luo
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Electrical Properties ◽  
Grain Boundaries ◽  
The Other ◽  
Leakage Currents ◽  
Donor Density ◽  
Zno Varistor ◽  
Zno Varistors ◽  
Simulation Results

The additive of Al(NO3)3 has been doped into ZnO varistors in order to reduce their residual voltages. However, the leakage currents of samples always increase at the same time. Generally, it is recognized that some of doped Al3+ ions enter the ZnO grains and reduce their resistivity, which results in lower residual voltages of varistor samples. On the other hand, the remnant Al3+ ions appear in the grain boundaries and also reduce their resistivity, which results in larger leakage currents. In this paper, the electrical properties of ZnO varistor samples with various amounts of Al(NO3)3 dopant were measured. The experimental data are compared with the numerical simulation results, which reveals that the increased leakage currents of ZnO varistors with Al(NO3)3 dopant are not only due to the decreased resistivity of grain boundaries, but also the increased donor density of ZnO grains.

Avalanche Features in Silicon Schottky-FETs in Accordance with Numerical Simulation Results

2006 ◽  
Vol 65 (16) ◽  
pp. 1533-1546
Author(s):  
Yu. Ye. Gordienko ◽  
S. A. Zuev ◽  
V. V. Starostenko ◽  
V. Yu. Tereshchenko ◽  
A. A. Shadrin
Keyword(s):  
Numerical Simulation ◽  
Simulation Results

An Intuitionistic Fuzzy Based Novel Approach to CPU Scheduler

2020 ◽  
Vol 16 (4) ◽  
pp. 316-328
Author(s):  
Supriya Raheja
Keyword(s):  
Fuzzy Inference ◽  
The Other ◽  
Simulation Environment ◽  
Inference System ◽  
Intuitionistic Fuzzy ◽  
Novel Approach ◽  
Continuous Feedback ◽  
Simulation Results ◽  
Effectiveness And Efficiency ◽  
Unique Capability

Background: The extension of CPU schedulers with fuzzy has been ascertained better because of its unique capability of handling imprecise information. Though, other generalized forms of fuzzy can be used which can further extend the performance of the scheduler. Objectives: This paper introduces a novel approach to design an intuitionistic fuzzy inference system for CPU scheduler. Methods: The proposed inference system is implemented with a priority scheduler. The proposed scheduler has the ability to dynamically handle the impreciseness of both priority and estimated execution time. It also makes the system adaptive based on the continuous feedback. The proposed scheduler is also capable enough to schedule the tasks according to dynamically generated priority. To demonstrate the performance of proposed scheduler, a simulation environment has been implemented and the performance of proposed scheduler is compared with the other three baseline schedulers (conventional priority scheduler, fuzzy based priority scheduler and vague based priority scheduler). Results: Proposed scheduler is also compared with the shortest job first CPU scheduler as it is known to be an optimized solution for the schedulers. Conclusion: Simulation results prove the effectiveness and efficiency of intuitionistic fuzzy based priority scheduler. Moreover, it provides optimised results as its results are comparable to the results of shortest job first.

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

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