• Title/Summary/Keyword: 로터 블레이드

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Unsteady Aerodynamic Analysis for Helicopter Rotor in Hovering and Forward Flight Using Overlapped Grid (중첩 격자를 이용한 제자리 및 전진 비행하는 헬리콥터 로터의 비정상 공력해석)

  • Im, Dong-Kyun;Wie, Seong-Yong;Kim, Eu-Gene;Kwon, Jang-Hyuk;Lee, Duck-Joo;Park, Soo-Hyung;Chung, Ki-Hoon;Kim, Seung-Bum
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.3
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    • pp.215-223
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    • 2009
  • In this paper, the helicopter aerodynamics is simulated in hovering and forward flight. Also, an overlapped grid technique is applied in this simulation to consider the blade motion and moving effects. The Caradonna & Tung's rotor blade was selected to analyze the unsteady aerodynamics in hovering and non-lift forward flight. Also, the AH-1G rotor blade was selected in forward flight. In forward flight case, the numerical trim was applied to determine the cyclic pitching angles using Newton-Raphson method, and the numerical results were in good agreement with experimental data, especially, the BVI effects were well simulated in advancing side in comparison other numerical results. The governing equation is a three dimensional unsteady Euler equation, and the Riemann invariants condition is used for inflow and outflow at the boundary.

Experimental Study on the Evolution of Tip Vortex Structures Generated by a Two-Bladed Rotor (2개의 블레이드로 구성된 회전익 끝와류들의 간섭 특성)

  • Sohn, Yong-Joon;Park, Byung-Ho;Han, Yong-Oun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.7
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    • pp.709-715
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    • 2011
  • In order to observe the wake interaction between tip vortices generated by a two-bladed rotor with slightly different pitch angles, the velocity components of the tip vortices were measured by using a two-dimensional LDV system. It was observed that the swirl velocity components of the ensuing blade deviated from the Vatistas' n = 2 vortex model and the axial velocity components of the preceding blade deviated from the Gaussian profile. It was also found that in the wake-age range of $200^{\circ}$ to $240^{\circ}$, the filament of the ensuing blade tip vortex was stretched as result of the closing in of two vortices. The results from these observations suggest the possibility that a similar wake interaction is generated in actual rotor blades, especially, in the ones with articulated hubs.

Design of KUH Main Rotor Small-scaled Blade (KUH 주로터 축소 블레이드 설계)

  • Kim, Do-Hyung;Kim, Seung-Ho;Han, Jung-Ho
    • Aerospace Engineering and Technology
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    • v.8 no.1
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    • pp.32-41
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    • 2009
  • In this study, scale-down design of full-scale Korean Utility Helicopter (KUH) main rotor blade has been investigated. The scaled model system were designed for the measurement of aerodynamic performance, tip vortex and noise source. For the purpose of considering the same aerodynamic loads, the Mach-scale method has been applied. The Mach-scaled model has the same tip Mach number, and it also has the same normalized frequencies. That is, the Mach-scaled model is analogous to full-scale model in the view point of aerodynamics and structural dynamics. Aerodynamic scale-down process could be completed just by adjusting scaling dimensions and increasing rotating speed. In the field of structural dynamics, design process could be finished by confirming the rotating frequencies of the designed blade with the stiffness and inertial properties distributions produced by sectional design. In this study, small-scaled blade sectional design were performed by applying domestic composite prepregs and structural dynamic characteristics of designed model has been investigated.

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Numerical study to Determine Optimal Design of 500W Darrieus-type Vertical Axis Wind Turbine (500W 급 다리우스형 풍력발전기의 최적설계를 위한 수치적 연구)

  • Lee, Young Tae;Lim, Hee Chang
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.8
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    • pp.693-702
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    • 2015
  • This paper presents the performance characteristics of a Darrieus-type vertical-axis wind turbine (VAWT) with National Advisory Committee for Aeronautics (NACA) airfoil blades. To estimate the optimum shape of the Darrieus-type wind turbine in accordance with various design parameters, we examine the aerodynamic characteristics and separated flow occurring in the vicinity of the blade, the interaction between the flow and blade, and the torque and power characteristics that are derived from it. We consider several parameters (chord length, rotor diameter, pitch angle, and helical angle) to determine the optimum shape design and characteristics of the interaction with the ambient flow. From our results, rotors with high solidity have a high power coefficient in the low tip-speed ratio (TSR) range. On the contrary, in the low TSR range, rotors with low solidity have a high power coefficient. When the pitch angle at which the airfoil is directed inward equals $-2^{\circ}$ and the helical angle equals $0^{\circ}$, the Darrieus-type VAWT generates maximum power.

Airfoil Aerodynamic Analysis for the Helicopter Rotor Blade Preliminary Design (헬리콥터 로터 블레이드 예비설계를 위한 에어포일 공력 해석)

  • Kim, Sang-Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.6
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    • pp.21-30
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    • 2005
  • The aerodynamic analysis of helicopter rotor airfoils was performed to generate the basic data for selection and distribution of airfoils at the helicopter rotor blade preliminary design phase.10 airfoils were chosen among the existing rotor airfoils, and the tabulated aerodynamic coefficients which are proper for the aerodynamic analysis using blade element theory were generated. Considering analysis cost, the simple mathematical models were chosen before the wind tunnel test to generate the aerodynamic characteristic curves($C_{l},C_{m},C_{d}$) in full AoA range($-180^{o}\sim180^{o}$) including the reverse flow region. The essential data necessary to the generation of the complete curves were obtained by using the IBLM(Interactive Boundary Layer Method). The generated aerodynamic characteristic curves agree with experimental results qualitatively. Finally, the aerodynamic characteristics of all 10 airfoils were compared and classified according to their own lift or moment characteristics.

A Study on Experimental Test of a Small Scale Hingeless Rotor (축소형 무힌지 로터 시험에 관한 연구)

  • Kim, Joune-Ho;Song, Keun-Woong;Joo, Gene;Suk, Jin-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.12
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    • pp.1599-1606
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    • 2011
  • It is possible to study the load characteristics of full-scale hingeless rotor with the changing of physical smallscaled configurations such as rectangular and paddle blades, and metal and composite hubs. In this study, a static test, and a ground and wind-tunnel test were carried out using small-scale rotor models. The static test was carried out to confirm structural stiffness, characteristics of inertia, natural frequency, and damping ratio of rotors, and the ground and wind-tunnel test was carried out to confirm the stability and aerodynamic characteristics under hovering and forward flight conditions. According to the test results, the vertical load in the case of a combination of a small composite hub with paddle blades was higher than that in the case of a metal hub with paddle blades at same condition. Further, it was confirmed that the restraint of the combination of composite hub can be more flexible than the metal hub for the motion of paddle blades.

Structural Analysis and Shape Optimization for Rotor of Turbomolecular Pump Using P-Method (P-기법을 이용한 터보분자펌프 로터의 구조해석 및 형상최적설계)

  • Won, Bo Reum;Jung, Hae Young;Han, Jeong Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.10
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    • pp.1279-1289
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    • 2013
  • In recent times, turbomolecular pumps (TMPs) have been used frequently to generate and maintain high and clean vacuum. Because of the high-speed rotation of the rotor, its structural safety should be treated as the first design concern. This paper presents the structural analysis and optimization of rotor blades of a TMP. To increase the numerical efficiency in the finite element modeling and analysis, the P-method provided in Pro/ENGINEER was used for simulation. The structural responses for several types of rotor blades were investigated, and the effects of the blade angle, blade length, and round size are thoroughly studied for each type of TMP blade. In addition, structural optimization to reduce and even the maximum stress at each stage of the TMP by changing the size of rounds between the blade and the hub was performed very successfully by using the P-method.

Aerodynamic Shape Optimization of Helicopter Rotor Blades in Hover Using a Continuous Adjoint Method on Unstructured Meshes (비정렬 격자계에서 연속 Adjoint 방법을 이용한 헬리콥터 로터 블레이드의 제자리 비행 공력 형상 최적설계)

  • Lee, S.-W.;Kwon, O.-J.
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.1
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    • pp.1-10
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    • 2005
  • An aerodynamic shape optimization technique has been developed for helicopter rotor blades in hover based on a continuous adjoint method on unstructured meshes. The Euler flow solver and the continuous adjoint sensitivity analysis were formulated on the rotating frame of reference for hovering rotor blades. In order to handle the repeated evaluation of the design cycle efficiently, the flow and adjoint solvers were parallelized using a domain decomposition strategy. A solution-adaptive mesh refinement technique was adopted for the accurate capturing of the tip vortex. Applications were made for the aerodynamic shape optimization of Caradonna-Tung rotor blades and UH60 rotor blades in hover. The results showed that the present method is an effective tool to determine optimum aerodynamic shapes of rotor blades requiring less torque while maintaining the desired thrust level.

Efficient Analysis of the Aerodynamic Characteristics of Rotor Blade Using a Reduced Order Model Based on Proper Orthogonal Decomposition Method (적합직교분해를 이용한 로터 블레이드의 차수축소모델 구축 및 공력특성 분석)

  • Jung, Sung-Ki;Duc, NgoCong;Yang, Young-Rok;Cho, Tae-Hwan;Myong, Rho-Shin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.11
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    • pp.1073-1079
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    • 2009
  • The proper orthogonal decomposition (POD) method can identify principal modes that optimally capture the energy content from large multi-dimensional data set. In this study unsteady pressure fields on the rotor blade surface of a helicopter in forward flight are expressed by a reduced order model based on the POD method. Special modes containing high energy are analyzed to investigate the aerodynamic characteristics in more efficient way. The CFD simulation of flowfields around helicopter rotor blade in hovering motion is also conducted to validate its prediction with experimental result. In the process 7 modes containing energy ratio 99% from 240 snapshots information are identified and utilized to construct a reduced order model.

The Extension and Validation of OpenFOAM Algorithm for Rotor Inflow Analysis using Actuator Disk Model (Actuator Disk 모델 기반의 로터 유입류 해석을 위한 OpenFOAM 알고리즘 확장)

  • Kim, Tae-Woo;Oh, Se-Jong;Yee, Kwan-Jung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.12
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    • pp.1087-1096
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    • 2011
  • The purpose of current study is to develop and verify the newly developed solver for analyzing rotor flow using the open-source code. The algorithm of standard solver, OpenFOAM, is improved to analyze the rotor inflow with and without fuselage. For the calculation of the rotor thrust, the virtual blade method based on the blade element method is employed. The inflow velocities on the rotor disk used to specify the effective angle of attack, have been included in the solver. The results of the current rotor inflow analysis are verified by comparing with other experimental and numerical results. It was confirmed that the modified solver provides satisfactory results for rotor-fuselage interaction problem.