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Song Xueguan,Li Qingye,Liu Fuwen,Zhou Weihao,Zong Chaoyong 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.8
A pressurized vessel-pipe-safety valve (PVPSV) combination is a commonly used configuration in nuclear power plants, and a good numerical model is essential for the system design, sizing and performance optimization. However, owing to the large-scale and cross-scale features, it is still a challenge to build a system level numerical model with both high accuracy and efficiency. To overcome this, a novel system level modeling method which can synthesize the advantages of various models is proposed in this paper. For system modeling, the analytical approach, the method of characteristics (MOC) and the surrogate model approach are respectively adopted to predict the dynamics of the pressure vessel, the connecting pipe and the safety valve, and different models are connected through data interfaces. With this system model, dynamic simulations were carried out and both the stable and the unstable system responses were obtained. For the model verification purpose, the simulation results were compared with those obtained from experiments and full CFD simulations. A good agreement and a better efficiency were obtained, verifying the ability of the model and the feasibility of the modeling method proposed in this paper
Numerical Investigation of a Liquid-Gas Ejector Used for Shipping Ballast Water Treatment
Song, Xueguan,Cao, Maosen,Shin, Wonhyup,Cao, Wenping,Kang, Sanghoon,Park, Youngchul Hindawi Limited 2014 Mathematical problems in engineering Vol.2014 No.-
<P>Shipping ballast water can have significant ecological and economic impacts on aquatic ecosystems. Currently, water ejectors are widely used in marine applications for ballast water treatment owing to their high suction capability and reliability. In this communication, an improved ballast treatment system employing a liquid-gas ejector is introduced to clear the ballast water to reduce environmental risks. Commonly, the liquid-gas ejector uses ballast water as the primary fluid and chemical ozone as the secondary fluid. In this study, high-pressure water and air, instead of ballast water and ozone, are considered through extensive numerical and experimental research. The ejector is particularly studied by a steady three-dimensional multiphase computational fluid dynamics (CFD) analysis with commercial software ANSYS-CFX 14.5. Different turbulence models (including standardk-ε, RNGk-ε, SST, andk-ω) with different grid size and bubble size are compared extensively and the experiments are carried out to validate the numerical design and optimization. This study concludes that the RNGk-εturbulence model is the most efficient and effective for the ballast water treatment system under consideration and simple change of nozzle shape can greatly improve the ejector performance under high back pressure conditions.</P>
중심형 버터 플라이 밸브의 유동 Torque 계수의 예측에 대한 연구
송학관(Xueguan Song),오승환(Seung-Hwan Oh),강정호(Jung-Ho Kang),박영철(Young-Chul Park) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.2
Butterfly valves are commonly used as control valves in applications where the pressure drops required of the valves are relatively low. As the shutoff valve (on/off service) or throttling valves (for flow or pressure control), the higher order and the better precision of butterfly valves are required. Thus it's more and more essential to know the flow characteristic around the valve. Due to the fast progress of the flow visualization and numerical technique, it becomes possible to observe the flows around a valve and to estimate the performance of a valve. Researching these results did not gave only access to understand the process of the valve flows at different valve opening angles, but also was made to determine the accuracy of the employed method. Furthermore, the results of the three-dimensional analysis can be used in the design of butterfly valve in the industry.
송학관(Xueguan Song),강정호(Jung-Ho Kang),김승규(Seung-Gyu Kim),박영철(Young-Chul Park) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.4
The valve is used on control of flow in a ship. Flow coefficient of valve is very importance in the design of valve. In this paper, three-dimensional computer simulations by commercial code CFX were conducted to observe the valve type and to measure flow coefficient when valves with various angles and uniform incoming velocity were used in a piping system. By contrast, a group of experimental data is used to compare with the data obtained by CFX simulation to investigate the validity of numerical method.
Multiobjective Optimization of Beam Structure for Bogie Frame Considering Fatigue-Life Extension
Baek Seokheum,Song Xueguan,Kim Myungil,Kim Jaesung 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3
This paper addresses the multiobjective optimization of a brake end beam of a bogie frame with consideration of three elements: the stress, fatigue, and weight. A fi nite-element analysis (FEA) is performed to obtain the stress distribution of the component, and the stress-life method and fatigue notch factor are used for fatigue-life assessment based on the FEA results. Subsequently, the multiobjective optimization problem in the form of mathematical functions, which considers three objectives, is handled using the design of experiments, approximation technique, analysis of variance, multiobjective algorithm, and Pareto-optimal solution. Finally, the FEA is validated according to the optimal result to verify the accuracy of the optimization. The results of this study indicate that the proposed approach is very available and has potential for the optimal design of the components of the bogie frame and/or the bogie itself.
유한요소법을 이용한 Butterfly Valve의 Metal-Seat의 해석
이성민(Seong-Min Lee),송학관(Song Xueguan),강정호(Jung-Ho Kang),박영철(Young-Chul Park) 한국기계가공학회 2008 한국기계가공학회 춘추계학술대회 논문집 Vol.2008 No.-
This paper presents a Finite Element Analysis (FEA) developed using the commercial software ANSYS, and presents predicted contact pressure between Disc and Metal seat to estimate the sealing effect during closure. The result shows that this sealing mechanism using metal seat could satisfy the need for sealing well, and the metal seat is very safe under general conditions.
조영직(Young-Jik Jo),송학관(Xueguan Song),김세훈(Se-Hun Kim),강정호(Jung-Ho Kang),박영철(Young-Chul Park) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.6
Shape memory alloy (SMA)has been used to improve the tensile strength of composite materials. Because it produces compressive residual stress in the matrix by using its shape memory effect. In order to fabricate a shape memory alloy composite, TiNi alloy and A12024, Al606l were used as reinforcing material and matrix, respectively. In this study, TiNi/A12024 and TiNi/Al606l shape memory alloy composites were made by the hot press method. The fatigue limit of a shape memory alloy composite determined the volume ratio and reduction ratio. The probabilistic stress-life curve (P-S-N curve) about the shape memory alloy composite makes up using statistical method.
Design optimization of a nuclear main steam safety valve based on an E-AHF ensemble surrogate model
Zong Chaoyong,Shi Maolin,Li Qingye,Liu Fuwen,Zhou Weihao,Song Xueguan 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11
Main steam safety valves are commonly used in nuclear power plants to provide final protections from overpressure events. Blowdown and dynamic stability are two critical characteristics of safety valves. However, due to the parameter sensitivity and multi-parameter features of safety valves, using traditional method to design and/or optimize them is generally difficult and/or inefficient. To overcome these problems, a surrogate model-based valve design optimization is carried out in this study, of particular interest are methods of valve surrogate modeling, valve parameters global sensitivity analysis and valve performance optimization. To construct the surrogate model, Design of Experiments (DoE) and Computational Fluid Dynamics (CFD) simulations of the safety valve were performed successively, thereby an ensemble surrogate model (E-AHF) was built for valve blowdown and stability predictions. With the developed E-AHF model, global sensitivity analysis (GSA) on the valve parameters was performed, thereby five primary parameters that affect valve performance were identified. Finally, the ksigma method is used to conduct the robust optimization on the valve. After optimization, the valve remains stable, the minimum blowdown of the safety valve is reduced greatly from 13.30% to 2.70%, and the corresponding variance is reduced from 1.04 to 0.65 as well, confirming the feasibility and effectiveness of the optimization method proposed in this paper