• 한국유체기계학회 논문집
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• 제17권4호
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• pp.11-18
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• 2014

The recent high speed propeller with blade sweep is required to have high strength to get the thrust to fly at high speed. The high stiffness and strength carbon/epoxy composite material is used for the major structure and skin-spar-foam sandwich structural type is adopted for advantage in terms of the blade weight. As a design procedure for the present study, the structural design load is estimated through investigation on aerodynamic load and then flanges of spars from major bending loads and the skin from shear loads are sized using the netting rule and Rule of Mixture. In order to investigate the structural safety and stability, stress analysis is performed by finite element analysis code MSC. NASTRAN. It is found that current methodology of composite structure design is a valid method through the static structural test of prototype blade.

• 한국유체기계학회 논문집
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• 제3권2호
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• pp.31-35
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• 2000

In this research, the performance predictions of the submersible mixer were investigated. The variation of the performance characteristics by changing the impeller design parameters were discussed through the flow calculation results by using a commercial program, FLUENT. The performance of the submersible mixers is related to the velocity diffusion profiles downstream of the impeller and also the required input motor power to mix the fluid. In this study, the various design parameters such as the number of blade, the hub and tip diameters, the impeller blade profiles and revolution speed of the blades were taken for the fixed values. The blade sweep direction, the chord length distribution along with the radius of the blade and the inlet blade angle were changed to make different testing models. The flow calculation results show the effect of the changed design parameters on the performance of the submersible mixers and also give some helpful information for designing more efficient submersible mixers.

• 한국유체기계학회 논문집
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• 제15권6호
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• pp.11-17
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• 2012

The one way fluid structure interaction analysis on advanced propeller blade for next generation turboprop aircraft. HS1 airfoil series are selected as a advanced propeller blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. propeller geometry is generated by varying chord length and pitch angle at design point. Blade sweep is designed based on the design mach number and target propulsion efficiency. The aerodynamic characteristics of the designed Advanced propeller were verified by CFD(Computational Fluid Dynamic) and showed the enhanced performance than the conventional propeller. The skin-foam sandwich structural type is adopted for blade. The high stiffness, strength carbon/epoxy composite material is used for the skin and PMI(Polymethacrylimide) is used for the foam. Aerodynamic load is calculated by computational fluid dynamics. Linear static stress analysis is performed by finite element analysis code MSC.NASTRAN in order to investigate the structural safety. The result of structural analysis showed that the design has sufficient structural safety. It was concluded that structural safety assessment should incorporate the off-design points.

• 한국운동역학회지
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• 제16권4호
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• pp.49-59
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• 2006

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to sweep shot in ice hockey. The subjects of this study were five professional ice hockey players. The reflective makers were attached on anatomical boundary line of body. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and ice hockey stick were defined. 1. In three dimensional linear velocity of blade the Y axis showed maximum linear velocity almost impact, the X axis(horizontal direction) and the Z axis(vertical direction) maximum linear velocity of blade did not show at impact but after impact this will resulted influence upon hitting puck. 2. The resultant linear velocity of each segment of right arm showed maximum resultant linear velocity at impact. It could be suggest that the right arm swing patterns is kind of push-like movement. therefore the upper arm is the most important role in the right arm swing. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed flexion all around the wrist shot. The angular displacement of trunk in internal-external rotation showed internal rotation angle at the backswing top and and increased the angle after the impact. while there is no significant adduction-abduction. 4. The three dimensional anatomical angular displacement of trunk showed most important role in wrist shot. and is follwed by shoulder joints, in addition the movement of elbow/wrist joints showed least to the shot. this study result showed upperlimb of left is more important role than upperlimb of right.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.374-377
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• 2007

This paper deals with a pitch control for reducing load of the wind turbine system. To make a model of the wind turbine system, the Momentum Theory and Blade Element Theory are used. Considering wind shear, wind model was also built. Due to a difference of the wind speed between upper parts and lower parts of the sweep area, overturning moment of the wind turbine is generated. So, in this paper through analyzing of the system model of the wind turbine, a control algorithm which was able to achieve both maintaining power and reducing overturning moment was proposed. Using matlab simulink, controller performance was verified.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.887-892
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• 2003

A front-end cooling fan is designed and tested in the present study. The design technique is developed using the one-dimensional inviscid flow through the fan blade, the empirical equations, and the experimental correlations. Design data for the blade can be obtained for a given flow rate and a pressure rise. A parabolic function is used to generate a sweep of the fan. Characteristics of the blade geometry are discussed between the huh and the tip. The fan is tested in the fan test unit. The measured volume flow rate at the operating point is in good agreement with that of the design specifications. Sound pressure levels of the noise are predicted with the Ffowcs Williams-Hawkings equations. Calculation results of the sound pressure level(SPL) 1m away from the fan are obtained and cpmpared with the measured data.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.173-179
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• 2012

본 논문에서는 부분 흡입형 초음속 터빈의 로터 블레이드에 ${\pm}15^{\circ}$의 스윕 각도를 적용하여 그에 의한 효과와 공력 특성을 살펴보기 위해 정상상태 유동해석과 비정상상태 유동해석을 동시에 수행하고 그 결과를 비교해 보았다. 3차원 Navier-Stokes 유동해석에는 상용 코드인 FLUENT 6.3 Parallel을 사용하였다. 모든 계산 케이스들에서 정상상태 유동해석에 비해 비정상상태의 경우가 손실이 더욱 크게 나오는 결과를 나타내었다. 후방스윕(BSW)모델은 기준모델(NSW)에 비해 팁 간극으로 빠져나가는 누설 손실량을 줄이는데 큰 효과가 있었고 비정상상태 유동 해석에서는 로터 출구면 정효율의 증가현상이 더욱 뚜렷하게 나타났다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.439-443
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• 2002

In this study, three-dimensional incompressible viscous flow analysis and optimization using response surface method are presented for the design of a jet fan. Steady, incompressible, three-dimensional Reynolds averaged Wavier-Stokes equations are used as governing equations, and standard k-$\epsilon$ turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Sweep angles and maximum thickness of blade are used as design variables for the shape optimization of the impeller in response surface method. The experimental points which are needed to construct response surface are obtained from the D-optimal design and Full Factorial design and relations between design variables and response surface are examined.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2690-2695
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• 2007

This work presents numerical optimization for design of a blade stacking line of a low speed axial flow fan with a fast and elitist Non-Dominated Sorting of Genetic Algorithm (NSGA-II) of multi-objective optimization using three-dimensional Navier-Stokes analysis. Reynolds-averaged Navier-Stokes (RANS) equations with ${\kappa}-{\varepsilon}$ turbulence model are discretized with finite volume approximations and solved on unstructured grids. Regression analysis is performed to get second order polynomial response which is used to generate Pareto optimal front with help of NSGA-II and local search strategy with weighted sum approach to refine the result obtained by NSGA-II to get better Pareto optimal front. Four geometric variables related to spanwise distributions of sweep and lean of blade stacking line are chosen as design variables to find higher performed fan blade. The performance is measured in terms of the objectives; total efficiency, total pressure and torque. Hence the motive of the optimization is to enhance total efficiency and total pressure and to reduce torque.

• 한국태양에너지학회 논문집
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• 제23권3호
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• pp.55-61
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• 2003

This paper represents the effect of rotor geometry on the performance of a small-scale Wells turbine for wave energy conversion. In this study, four kinds of blade profile were selected from previous studies with regard to the blade profile of the Wells turbine. The experimental investigations have been performed for two solidities by model testing under steady flow conditions, and then the effect of blade profile on the running and starting characteristics under sinusoidal flow conditions have been investigated by a numerical simulation using a quasi-steady analysis. In addition, the effect of sweep on the turbine characteristics has been investigated for the cases of CA9 and HSIM 15-262123-1576. As a result, a suitable choice of these design factors has been suggested.