• 한국소음진동공학회논문집
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• 제23권2호
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• pp.105-111
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• 2013

Whirl tower test is conducted basically during helicopter rotor system development process. And for whirl tower test of rotor hub system, new design blade or existing blade which is remodeled for new rotor hub system is used. Because of simple shape and efficient aerodynamic characteristic, BO-105 helicopter blade is used for helicopter rotor hub development project widely. Originally BO-105 blade is used for hingeless hub system and blade root is used to flexure. So flap stiffness and lag stiffness at blade root area is relatively low compare with airfoil area. So, in order to apply the BO-105 blade to bearingless hub, blade root area have to be reinforced. And in this process, blade root area's section property is changed. In this paper, we suggest reinforcement method of BO-105 blade root area and study dynamic characteristic of bearingless rotor system with reinforcement BO-105 blade.

• International Journal of Aeronautical and Space Sciences
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• 제10권2호
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• pp.95-105
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• 2009

The flow fields around the HARTII rotor were numerically investigated using a viscous flow solver on adaptive unstructured meshes. An overset mesh and a deforming mesh technique were used to handle the blade motion including blade deflection, which was obtain from the HARTII experimental data. A solution-adaptive mesh refinement technique was also used to capture the rotor wake effectively. Comparison of the sectional normal force and pitching moment at 87% radial station between the two cases, with and without the blade deflection, showed that the blade loading is significantly affected by blade torsion. It was found that as the mesh was refined, the strength of tip vortex is better preserved, and the magnitude of high frequency blade loading, caused by blade-vortex interaction (BVI), is further magnified. It was also found that a proper time step size, which corresponds to the cell size, should be used to predict unsteady solutions accurately. In general, the numerical results in terms of the unsteady blade loading and the rotor wake show good agreement with the experimental data.

• 대한기계학회논문집B
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• 제29권5호
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• pp.625-632
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• 2005

This paper describes the shape optimization of a stator blade in a single-stage transonic axial compressor. The blade optimization has been performed using response surface method and three-dimensional Navier-Stokes analysis. Two shape variables of the stator blade, which are used to define a stacking line, are introduced to increase an adiabatic efficiency. Data points for response evaluations have been selected by D-optimal design, and linear programming method has been used for an optimization on a response surface. Throughout the shape optimization of a stator blade, the adiabatic efficiency is increased to 5.8 percent compared to that of the reference shape of the stator. The increase of the efficiency is mainly caused by the pressure enhancement in the stator blade. Flow separation on the blade suction surface of the stator is also improved by optimizing the stator blade. It is noted that the optimization of the stator blade is also useful method to increase the adiabatic efficiency in the axial compressor as well as the optimization of a rotor blade, which is widely used now.

• 항공우주시스템공학회지
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• 제6권1호
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• pp.1-6
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• 2012

During helicopter rotor system development process, whirl tower test is conducted basically. For conducting whirl tower test during bearingless hub development process, design new blade or using existing blade with repair or remodeling. Because simple shape and efficient aerodynamic characteristic, BO-105 blade is used for hub system development widely. Originally BO-105 Blade is used for hingeless hub, so flap stiffness and lag stiffness on blade root area is relatively low. So appling BO-105 blade to bearingless hub whirl tower test, root area have to be reinforce. In this paper, suggest reinforcement method of BO-105 blade root area.

• 한국생산제조학회지
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• 제21권5호
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• pp.784-789
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• 2012

Ultrasonic Cutting which uses a tuned blade resonant in a longitudinal mode, has been used to cut a range of materials from confectionery, baked products and frozen foods, to wood, bone, foams and composites. The Blade design typically uses finite element analysis, and it could be predicted vibration mode, gain and amplitude uniformity of the blade tip at resonant frequency. In this paper, FEA used to predict the vibration characteristic of the blade, and then the results were verified by analysis system of resonant frequency using the processed blade. The crack of the blade which is predicted from FEA was compared with the crack occurred by cutting experiment of rubber materials using the processed blade.

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.847-852
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• 2004

The wind turbine blade is the equipment converted wind into electric energy. The effect of the blade has influence of the output power and efficiency of wind turbine. The design of blade is considered of lift-to-drag ratio. structure. a condition of process of manufacture and stable maximum lift coefficient, etc. This study is used the simplified method for design of the aerodynamic blade and aerodynamic analysis used blade element method This Process is programed by delphi-language. The Program has any input values such as tip speed ratio blade length. hub length. a section of shape and max lift-to-drag ratio. The Program displays chord length and twist angle by input value and analyzes performance of the blade.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.631-638
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• 2003

The wind turbine blade is the equipment converted wind into electric energy. The effect of the blade has influence of the output power and efficiency of wind turbine. The design of blade is considered of lift-to-drag ratio, structure, a condition of process of manufacture and stable maximum lift coefficient, etc. This study is used the simplified method for design of the aerodynamic blade and aerodynamic analysis used blade element method. This process is programed by delphi-language. The program has any input values such as tip speed ratio, blade length, hub length, a section of shape and max lift-to-drag ratio. The program displays chord length and twist angle by input value and analyzes performance of the blade.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1465-1469
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• 2009

Darrieus wind turbine blade is one of the vertical wind power system in which the lift of blade is used. In the calculation of wind power for the type of that, the multiple streamtubes method is known as an effective method. But it has big difference in the region of higher tip speed ratio because the incoming air velocity is used in the calculation of lift. The incoming air velocity is reduced from inlet to outlet continually by transferring energy to the wind blade. In this study, the air velocity on the blade, which is called blade velocity, is obtained with newly developed algorithm and used to determine the lift. And it is verified that applying blade velocity on the lift calculation cause the power prediction to improve dramatically in the region of higher tip speed ratio.

• 대한구순구개열학회지
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• 제4권1호
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• pp.1-11
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• 2001

Disposable blade is widely used for palatal and oral mucosal incision in oral and maxillofadal surgery nowadays, But its design and durability need for improvement, Especially, there are so many hard tissues intraoral area, such as bone and tooth, therefor the sharpness of the surgical blade was easily destroyed, The purpose of this study was to make basic data for developing new design of surgical blade using in oral and maxillofacial area including for the patients who have cleft lip and palate deformities, Some questionnaires about the usefulness of currently used surgical blades were sent to 150 dentists, the 54 of them made a reply, Secondly, The used-once blade and fresh new blade were examined under the scanning electron microscope with the 4000-times magnification, Lastly, the tissue reaction following the surgical incision with a fresh-new and a used blade on rat buccal cheek mucosa and hard palate was evaluated with light microscope with hematoxilin-eosin staining, The time interval from the surgical trauma to taking a sample were 1 day, 3 days, 7 days, and 14 days, At each time schedule, 2 Sprague-Dawley rats were sacrificed, Many dentists were agreed to need for changing the design of the surgical blades and also demand to improve the durability of the blades, They were also eager to adopt the new design of blade if it was available, The blade used in surgical extraction procedure was heavily damaged in its sharpe edge of number 15 blade, The histological differences were not prominent, but the delayed healing was detected in buccal mucosal defects especially in the surgical group with used blade, There are slight different changes in hard palatal defects between a used and a new blade group, In this study, we could find that there are imperative demanding on improvement of surgical blade design and durability for oral and maxillofadal area, The blade currently using in surgical extraction was easily damaged, The animal model of this study was not perfect for the purpose of this study.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.622-627
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• 2012

During helicopter rotor system development process, whirl tower test is conducted basically. For conducting whirl tower test during bearingless hub development process, design new blade or using existing blade with repair or remodeling. Because simple shape and efficient aerodynamic characteristic, BO-105 blade is used for hub system development widely. Originally BO-105 blade is used for hingeless hub, ho flap stiffness and lag stiffness on blade root area is relatively low. So applying BO-105 blade to bearingless hub whirl tower test, root area have to be reinforce. In this process, blade root area's section property will be changed. In this paper, suggest reinforcement method of BO-105 blade root area and study dynamic characteristic of bearingless rotor system with reinforcement BO-105 blade.