Study on Gas Entrainment From Unstable Drifting Vortexes on Liquid Surface

2018 ◽  
Author(s):  
Moe Hirakawa ◽  
Yuichiro Kikuchi ◽  
Takaaki Sakai ◽  
Masaaki Tanaka ◽  
Hiroyuki Ohshima
Keyword(s):  
Water Surface ◽  
Evaluation Method ◽  
Liquid Surface ◽  
Design Method ◽  
Reactor Vessel ◽  
Energy Agency ◽  
Circulating Water ◽  
Gas Entrainment ◽  
Slit Flow ◽  
Study Evaluation

Gas entrainment (GE) from cover gas, which is an inert gas to cover Sodium coolant in a reactor vessel, is one of key issue for Sodium-cooled fast reactors (SFRs) design to prevent unexpected effects to core reactivity. In this study, evaluation method has been investigated for surface dimple depth growth of unstable drifting vortex dimples on the liquid surface in the reactor vessel. By using a computational fluid dynamics (CFD) code, analyses have been conducted to estimate the drifting vortexes on water experiments in the circulating water tunnel. The unstable drifting flow vortexes on the water surface were generated as wake vortexes behind a plate obstacle. Downward flow velocity was induced by bottom slit flow pass along the flow channel. In CFD analysis, flat water surface assumption was used with free-slip model for the development of a conventional design method. The gas core lengths from the surface vortexes were evaluated based on existing non-dimensional numbers method by using the stream-viewer code provided from Japan Atomic Energy Agency (JAEA). In this paper, the results of comparison between experiments and analyses were discussed.

Analysis of Gas Entrainment Phenomenon From Free Liquid Surface for a Sodium-Cooled Fast Reactor Design: Validation of Velocity Profile and Strouhal Number in a Flow Field

2020 ◽  
Author(s):  
Mao Uchida ◽  
Moe Hirakawa ◽  
Aaru Sano ◽  
Keisuke Inoue ◽  
Takaaki Sakai ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Flow Velocity ◽  
Liquid Surface ◽  
Velocity Profiles ◽  
Reactor Vessel ◽  
Flow Channel ◽  
Wake Flow ◽  
Gas Entrainment ◽  
Piv Method

Abstract Gas entrainment (GE) from cover gas, which is an inert gas to cover sodium coolant in a reactor vessel, is one of key issue for Sodium-cooled fast reactors (SFRs) design to prevent unexpected effects to core reactivity. In this research series, evaluation method has been investigated for surface dimple depth growth of unstable drifting vortex dimples on the liquid surface in the reactor vessel. By using a computational fluid dynamics (CFD) code, analyses have been conducted to estimate the drifting vortex on water experiments in a circulating water tunnel. The unstable drifting flow vortexes on the water surface were generated as wake vortexes behind a plate obstacle. Downward flow velocity was induced by bottom slit flow pass along the flow channel. In the previous study, the onset conditions of the gas entrainment were evaluated based on existing non-dimensional numbers method by using the STREAM-VIEWER code. However, the CFD predication accuracy of the detail flow field itself was not clear especially for vortex frequency in the wake flow and detail velocity profiles in the flow channel. In this study, to clarify the accuracy of CFD analysis, Strouhal numbers of vortex frequency and detail flow velocity profiles were compared with experimental data which were measured by Particle Image Velocimetry (PIV) method. As the results, the Strouhal numbers of the vortex frequency behind the plate obstacle reasonably agreed with experimental data. Prediction accuracy for the velocity profiles in the flow channel were also confirmed by comparisons with measured data by the PIV method.

Artifact Design and Measurement Error Analysis in the Evaluation of Lead Measurement Accuracy of Helical Gear Using Wedge Artifact

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Masaharu Komori ◽  
Fumi Takeoka ◽  
Aizoh Kubo ◽  
Kazuhiko Okamoto ◽  
Sonko Osawa ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Plane Surface ◽  
Design Method ◽  
Measuring Instrument ◽  
Setting Error ◽  
Geometrical Form ◽  
Measurement Experiment ◽  
Mechanical Devices ◽  
Tooth Flank ◽  
Artifact Design

The reduction in the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometer order; therefore, strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a helicoid artifact. However, it is difficult to manufacture it with high accuracy because the helix is a complicated geometrical form. To solve this problem, a method of evaluating a gear-measuring instrument using a wedge artifact, which includes a highly precise plane surface, has been proposed. In this research, to put the wedge artifact into practice, a design method of the wedge artifact is developed. In addition, the effects of the measuring condition and the setting error of the wedge artifact on the measurement result are investigated. The uncertainty for the evaluation method using a wedge artifact is assessed by a measurement experiment and simulation.

The Research of Design Method on Green Modular that Oriented Construction Machinery

2014 ◽  
Vol 1049-1050 ◽  
pp. 828-832
Author(s):  
J.R. Yang
Keyword(s):  
Evaluation Method ◽  
Modular Design ◽  
Comprehensive Evaluation ◽  
Design Method ◽  
Fuzzy Comprehensive Evaluation ◽  
Element Analysis ◽  
Construction Machinery ◽  
Comprehensive Evaluation Method ◽  
The Finite Element Analysis ◽  
Factor Evaluation

The aim of this study was to obtain the method of the green design and modular design that oriented construction machinery products. A variety of modern design tools such as the finite element analysis software package and optimize design package and a two-factor evaluation fuzzy modelare used to analyze and Evaluation the green degree and the module degree of the construction machinery. Some modern mathematical tools such as AHP and fuzzy comprehensive evaluation method are used to calculate and evaluate the green degree and the module degree in construction machinery design. The proposed design method can meet the requirements of the green degree and the module degree of the construction machinery.

scholarly journals Passive solar systems for buildings: performance indicators analysis and guidelines for the design

2020 ◽  
Vol 197 ◽  
pp. 02008
Author(s):  
Giacomo Cillari ◽  
Fabio Fantozzi ◽  
Alessandro Franco
Keyword(s):  
Performance Indicators ◽  
Energy Demand ◽  
Evaluation Method ◽  
International Energy Agency ◽  
Objective Evaluation ◽  
Design Guidelines ◽  
Design Strategies ◽  
Energy Agency ◽  
Solar Systems ◽  
Passive Solar

Data from the International Energy Agency confirm that in a zero-energy perspective the integration of solar systems in buildings is essential. The development of passive solar strategies has suffered the lack of standard performance indicators and design guidelines. The aim of this paper is to provide a critical analysis of the main passive solar design strategies based on their classification, performance evaluation and selection methods, with a focus on integrability. Climate and latitude affect the amount of incident solar radiation and the heat losses, while integrability mainly depends on the building structure. For existing buildings, shading and direct systems represent the easiest and most effective passive strategies, while building orientation and shape are limited to new constructions: proper design can reduce building energy demand around 40%. Commercial buildings prefer direct use systems while massive ones with integrated heat storage are more suitable for family houses. A proper selection must consider the energy and economic balance of different building services involved: a multi-objective evaluation method represents the most valid tool to determine the overall performance of passive solar strategies.

A general evaluation method for the diabatic journal bearing

1974 ◽  
Vol 336 (1606) ◽  
pp. 307-325 ◽  
Keyword(s):  
Evaluation Method ◽  
Journal Bearing ◽  
Design Method ◽  
Three Dimensional ◽  
Algebraic Equations ◽  
Mixing Conditions ◽  
General Evaluation ◽  
Wide Range ◽  
Energy Equations ◽  
Independent Parameters

A design method is described for the steadily loaded, full journal bearing. This is presented as a non-iterative set of algebraic equations, where a dependent bearing parameter, e. g. eccentricity or power-loss, is predicted in terms of known independent parameters which include bearing geometry, running conditions and oil characteristics. The method is developed from a regression analysis of accurately computed, fully thermohydrodynamic, solutions for the bearing. These solutions are generated by simultaneously solving the Reynolds and energy equations in the oil film, the Laplace equation in the bearing material and the oil-mixing conditions at inlet. A quasi three-dimensional finite-difference technique is used. Both the particular solutions and the predictions of the design method compare favourably with a wide range of experimental data, the latter showing an improvement in accuracy and economy on existing design methods.

Fuzzy Synthesized Evaluation of Product Quality of Machine Tool Based on Harmonious Design Method

2009 ◽  
Vol 16-19 ◽  
pp. 1382-1386
Author(s):  
Chun Shi Liu ◽  
Xiao Peng Li ◽  
Wei Sun ◽  
Yi Min Zhang
Keyword(s):  
Machine Tool ◽  
Product Quality ◽  
Evaluation Method ◽  
Design Method ◽  
Price Ratio ◽  
Design Quality ◽  
Product Function ◽  
Working Capability ◽  
One Machine

In this work, it is presented and studied that the harmonious of product function with capability, harmonious of product with product, harmonious of product with people, with technology, with society environment, with entironment from the view of entironment, society, economy, science, politics, culture and legal point in the design process. And the quality verification and evaluation methods are studied to enhance the design quality more effectively. And that, all the studied contents is named harmonious design method. One machine tool is used as an example to explain the method with design quality evaluated by fuzzy synthesized evaluation method from function, structure capability, working capability and craftwork capability factors. The grade and disparity of design quality are obtained through the evaluation results, then design project could be modified based on it, and it is very useful to improve product quality and to enhance performance-price ratio and market competitive ability.

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