• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.661-662
• /
• 2009

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.6
• /
• pp.1726-1732
• /
• 2008

Injection molding is one of plastic forming technology which can easily mass-produce plastic parts with various and even complex shape. The technology has lots of difficulties in making a good part due to phase change of material, high applied pressure, and fast melt flow speed in the cavity. To overcome the problems, they had to make trial and error method until the CAE(Computer Aided Engineering) could be a tool for concurrent engineering. In this paper, we investigate the optimal design for a plastic DVD tray part by systematic approach of the commercial CAE program. In design, we should consider two objectives which are both dimensional stability and cost-down. The dimension of the part is crucial because the tray should carry a DVD correctly, but the part is too thin to injection-mold easily. In order to improve the moldability, the mold is designed in the form of stack mold which is a kind of 4 hot runner system. In first, we changed the stack-mold system with one hot-runner to cost down, and decided the optimal position of the gate. After that, we investigate the effect of both the layout of cooling channels and the cooling temperature on the shrinkage of the DVD tray. A optimal simulation approach, the gate design is 2Gate#3 and the layout is Case2 cooling line as the optimal temperature of $70^{\circ}C$. The Moldflow and PC+ABS are used for the CAE program and material respectively.

• The KSFM Journal of Fluid Machinery
• /
• v.17 no.2
• /
• pp.5-11
• /
• 2014

Small hydro power, among other renewable energy resources, has been evaluated to have enough development value because it is a clean, renewable and abundant energy resource. In addition, small hydro power has the advantage of low cost development by using existing facilities like sewage treatment plants, water works and similar resources. But in the case of small hydro power systems, there are problems with degraded operation efficiency of turbine due to changes in flow rates. In order to overcome this, variable speed control can be achieved by using the power rectifier and permanent magnetic synchronous generator(PMSG) as a possible method to respond to the changes in flow rates. In this study, a commercial ANSYS CFD code was used to analyze the performance of 10kW class propeller hydro turbine and to also investigate flow characteristics at variable flow rates and runner vane.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.2
• /
• pp.115-122
• /
• 2014

Injection pressure is one of factors that influence part quality. In this paper, injection pressure was minimized by optimizing valve gate locations. In order to perform design optimization, MAPS-3DTM (Mold Analysis and Plastic Solution-3D) was used for injection mold analysis and PIAnOTM (Process Integration, Automation and Optimization) was used as process integration and design optimization. Also we adapted meta models based on design of experiments for efficiency. By using introduced methodology, we were able to obtain a result so that maximum injection pressure reduced by 28% compared to the initial design. And the validity of the proposed method could also be demonstrated.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.3
• /
• pp.225-232
• /
• 2017

Several maintenance issues related to cavitation erosion and fatigue cracks in the water turbine subcomponents of pumped-storage plants, such as a runner and a draft tube, have been reported in the past. Generally, the pumped-storage plants provide ancillary services, such as black-start and system stabilization. The ancillary services are responsible for cyclic low opening operation of the guide vanes. It has been empirically established that this low opening operation further damages the water turbine subcomponents. In this study, the acceleration effect of the low opening operation on the cavitation erosion and fatigue of the water turbine is quantitatively assessed through finite element flow analysis, finite element stress analysis, and fatigue analysis. As a result of the assessment, it is identified that the cavitation potential increases and the turbine efficiency decreases with a decrease in the opening of the guide vane. Also, the low opening operation has an insignificant effect on the fatigue even though it increases the maximum stress values at the runner blade roots.

• Proceedings of the KAIS Fall Conference
• /
• 2001.05a
• /
• pp.249-252
• /
• 2001

본 논문은 사출성형제품의 런너시스템 설계를 합리적으로 수행하기 위해 사출금형설계전문가의 축적된 지식과 경험을 발췌ㆍ정리하여 지식베이스를 작성하였으며, 설계에 필요한 제품의 형상정보를 제공하기 위해 총칭형상과 특징형상 개념을 이용하여 특징형상을 정의하였다. 또한 지식베이스를 통해 산출된 설계결과를 기하학적 모델러와의 인터페이스를 통해 3차원 형상으로 보여지도록 하였으며, 최종 생성된 3차원 기하학적 형상정보는 CAE 모듈이나 CAPP 모듈에서의 후속작업을 위해 제공될 수 있도록 구축되었다.

• The KSFM Journal of Fluid Machinery
• /
• v.16 no.1
• /
• pp.17-23
• /
• 2013

Recently so much attention has been focused on renewable energy and, since its sources to exploit are already almost saturated in the country, the practical alternative to this situation could be a micro-turbine which uses the low head and low flow. From a point of view of local micro-turbine design capacity and manufacturing technology, the problems such as the accumulation of technical skills, the expansion of related industries, the national policy expansion and the turbine efficiency to improve are still vulnerable and it's true that there are also negative views about the economic feasibility, the technicity and the operation management of the micro-turbine. However, if the improvement can be done in technology of low-head double regulation micro-turbine to generate more outputs and the operation management can be reliably realized, the micro-turbine will be re-evaluated as an appliable source of renewable energy, even the output is small, and by a paradigm shift, it could realize a power generation as an economic and rational system.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.2
• /
• pp.9-18
• /
• 2000

Combustion and emission characteristics in a direct injection diesel engine is closely related to the intake port system. It is therefore important to understand the swirl flow characteristics formed by a helical intake port. However there are still many uncertainties. The purpose of this experimental study is to investigate the effects of the valve eccentricity ratio and the inlet flow conditions of a helical intake port on the characteristics of an in-cylinder swirl flow. A steady state flow test rig consisted of ISM(impulse swirl meter), LFM(laminar flow meter) and cylinder head with a helical intake port was used. The swirl ratio(Rs) and mean flow coefficient(Cf(mean)) with inlet flow conditions were measured. The results of these experiment can be summarized as follows. Swirl flow characteristics of a helical intake port are affected by the inlet flow conditions, and especially they are much affected by the length of a manifold runner and the rotational angle of a curved manifold runner.

• Journal of People, Plants, and Environment
• /
• v.23 no.6
• /
• pp.615-624
• /
• 2020

Background and objective: Urbanization caused a reduction in urban green space and a lack of community spaces. An attempt to solve these problems, urban gardens, have become popular and are currently being implemented in various downtown areas. However, urban gardens have some inadequate aspects from a visual or landscape perspective. The goal of this study was to examine the possibility of an aesthetic and productive garden space by introducing cultivation methods through the planting system design process. Methods: The design process using plants was classified and presented to suggest the importance of the landscape and aesthetic value. An urban garden space was designed according to the perspective of 'production scenery' and 'participation aesthetics'. According to the characteristics of the plant, urban gardens were divided into vertical type (corn, millet, sorghum), climbing type (kidney bean, cucumber, bitter gourd), and runner type (melon, watermelon, peanut). After classifying plants according to the shape of the root, the structure supporting climbing was installed and the crops were cultivated in an upright form with a tunnel. Results: In the designed cultivation, each crop cooperates, without invading each other's space. Compared with the conventional cultivation, there was little difference in production, and management was made more convenient since weed outbreaks were effectively suppressed while runner type crops cover over the land's surface. Since the positions of each crop are clearly distinguished, the aesthetic value is improved by offering a sense of rhythm with a balanced design. Conclusion: The results suggest that the cultivation methods through the plant system design process have aesthetic as well as productive value, and the design using plants, an infinite living resource, could lead to an expansion of the design field. Moreover, it would enable a sustainable symbiosis between industry and environment. There is potential for the design industry to make significant progress through collaboration with agriculture, horticulture, and landscape architecture.

• Proceedings of the KAIS Fall Conference
• /
• 2004.11a
• /
• pp.73-76
• /
• 2004

본 연구는 사출 성형에 있어서의 불량과 그에 따른 해결책을 Visual Basic을 이용하여 전산 정보화함으로써 성형 불량 대책을 제공, Gate와 Runner를 최적화하는 지적 결정 시스템을 개발하였다. 체계적인 기술이 정립되어 있지 않는 플라스틱 성형의 문제점을 최소화하고 재료비 절감, 설계 납기일 단축, 제품 품질 향상을 그 목적으로 하고 있다.