• Journal of Aerospace System Engineering
• /
• v.13 no.1
• /
• pp.69-76
• /
• 2019

In this study, resin flow analysis of resin transfer moulding (RTM) method was performed for mould design of composite structure. The target composite structure was a tank used for fluid storage. Natural c fiber composite was adopted for composite structural design of the fluid storage tank. RTM was adopted for manufacturing of the tank using natural fiber composites. Resin flow analysis was performed to find the proper RTM conditions of the tank. The resin flow analysis was performed using the commercial FEM flow simulation software. After repeated analysis while changing the location of resin inlet and outlet, the proper resin filling time and pattern were found.

• Aerospace Engineering and Technology
• /
• v.11 no.1
• /
• pp.126-134
• /
• 2012

The Single Species, Unreacted Flow Model which is effectively applicable on the computational analysis of rocket exhaust flow is introduced in this paper. The basic concept of this model had been originated from chemically frozen analysis of hot air but it was complemented by compensating molecular weight and specific heat which was obtained CEA code analysis of exhaust plume. Comparing single species, unreacted model with the finite chemistry model, unreacted model can reduce calculation time to 1/5 while it makes similar simulation results.

• 전기의세계
• /
• v.45 no.2
• /
• pp.17-24
• /
• 1996

차단기의 개발과정은 크게 모의시험, 설계 및 제작, 성능시험 3가지로 나누어 볼 수 있다.이 중에서 모의 시험은 일반적으로 해석기술에 의해 주로 이루어지며, 차단기에 적용되는 해석기술은 1) 차단부 전계해석 2) 차단부 냉가스 유동해석 3) 차단부 열가스 유동해석(차단성능해석) 4) 차단기 동작특성해석 5) 차단기 응력해석 및 구조해석으로 대별할 수 있다. 상기의 해석기술은 적용하는 해석방법에 따라 다소 차이가 있지만, 1992년부터 당 연구팀이 개발중인 800kV 40kA 4000A 차단부를 개발하는 과정에 적용한 해석수법을 중심으로 살펴보기로 한다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.4
• /
• pp.665-670
• /
• 2006

In this paper, the results of empirical methods and the numerical analysis were compared and investigated on the lateral displacement due to embankment in soft soil. The empirical methods gave different results so the possibility of lateral displacement could not be determined only by the empirical methods. The numerical analysis could be used so effectively that its result showed useful lateral and vertical displacements with depth and distance.

• Proceeding of EDISON Challenge
• /
• 2012.04a
• /
• pp.105-108
• /
• 2012

이차원 단면 Cylinder는 외부유동상태에서 후류에 Vortex를 생성한다. 또한 비정상 유동 상태에서는 후류에 카르만 Vortex열을 생성한다. 이런 이차원 Cylinder는 여러 분야에서 사용 된다. 이때 적절한 설계를 위해 수치적으로 유동을 해석할 필요가 있다. 이에 대한 수치적 해석 값을 얻기 위해 Edison CFD를 이용하여 여러 2차원 형상 Cylinder의 Reynolds number에 따른 Vortex shedding을 해석했다. Edison CFD를 통한 시뮬레이션 결과 값에 대한 검증을 얻기 위해 원형, 사각형의 Vortex shedding과 유동을 타 논문과 비교 검증했다. 형상마다 같은 조건의 Reynolds number라도 후류와 유동 등의 형상이 차이를 보인다. 상황마다 적절한 모형의 Cylinder를 Edison CFD를 통해 예측 할 수 있다.

• Proceedings of the KAIS Fall Conference
• /
• 2010.05b
• /
• pp.992-995
• /
• 2010

엔진 흡기시스템 중 흡기매니폴드는 가솔린엔진의 성능을 결정하는 매우 중요한 성능 인자이다. 본 연구에서는 1400cc급 가솔린 엔진용 흡기 매니폴드에 대한 유동해석과 리그 실험을 수행하였다. 압력차에 따른 유동 및 유량계수의 해석을 통하여 유동특성을 분석하였으며 실험적 평가를 통하여 공기유량계수의 결과치를 검증하였다. 해석과 실험 결과를 비교 분석하여, 해석값과 실험값의 오차를 확인하였다.

• Journal of Aerospace System Engineering
• /
• v.14 no.1
• /
• pp.8-15
• /
• 2020

In this paper, we propose a container wall and its boundary layer insulation design method that can maintain the temperature inside the spacecraft shipping container constantly under the condition that the heat or the external temperature changes severely to safely transport the satellite to the launch site. We will examine if the temperature inside the satellite shipping container is kept constant through the heat flow analysis and the satellite heat transfer analysis for the external environment of the satellite shipping container. Through the flow analysis inside the container, the flow distribution around the satellite in the container is analyzed, and the auxiliary fan, air conditioning system and special grill guide structure design for improving and optimizing heat flow performance are proposed.

• Journal of the Microelectronics and Packaging Society
• /
• v.8 no.4
• /
• pp.67-72
• /
• 2001

An Effort has been made to more accurately analyze the flow in the chip cavity, particularly to model the flow through the openings in the leadframe and correctly treat the thermal boundary condition at the leadframe. The theoretical analysis of the flow has been done by using the Hele-Shaw approximation in each cavity separated by a leadframe. The cross-flow through the openings in the leadframe has been incorporated into the Hele-Shaw formulation as a mass source term. The optimization program based on the complex method integrated with flow analysis program has been successfully used to obtain the optimal filling conditions to avoid short shot.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.173-179
• /
• 2012

Steady and unsteady three-dimensional RANS simulations have been performed on partial admission supersonic axial turbine having backward/forward sweep angles(${\pm}15^{\circ}$) and the results are compared with each other. The objective of this paper is to study the effect of unsteadiness on turbine flow characteristics and performances. The all results indicated that the losses of unsteady simulations were greater than those of steady cases. It was also shown that BSW model give the effect on the reducing of mass flow rates of tip leakage. In unsteady simulation, the increase of t-to-s efficiency at Rotor Out plane was observed more clearly.

• Tunnel and Underground Space
• /
• v.10 no.2
• /
• pp.173-179
• /
• 2000

The influence of the plastic flow rules on the elasto-plastic behaviour of a discrete joint element was investigated by performing the numerical direct shear tests under both constant normal displacement and normal displacement conditions. The finite interface elements obeying Plesha’s joint constitutive law was used to allow the relative motion of the rock blocks on the joint surface. Realistic results were obtained in the tests adopting the non-associated flow rule, while the associated flow rule overestimated the joint dilation. To overcome the computational drawbacks coming from the non-symmetric element stiffness matrix in the conventional non-associated plasticity, the symmetric formulation of the tangential stiffness matrix for a non-associated joint element was proposed. The symmetric elasto-plastic matrix it derived by assuming an imaginary equivalent joint with associated flow rule which shows the same plastic response as that of original Joint with non-associated flow rule. The validity of the formulation was confirmed through the numerical direct shear tests under constant normal stress condition.