• Title/Summary/Keyword: 風洞

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Wind Tunnel Test on Propellers for Middle Size Electric Propulsion UAV (중형 전기추진 무인기용 프로펠러 풍동시험)

  • Park, Poo-Min;Hwang, Oh-Sik;Kim, Young-Mun;Kim, Chun-Taek;Kwon, Ki-Jung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.784-788
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    • 2011
  • Wind tunnel test on 20" class propellers are carried out at KARI's low speed wind tunnel (LSWT). The test was done to select most efficient propeller for middle size electric propulsion UAV of KARI. The propellers are commercially available 20" class folding type propellers made of carbon fiber composite material. As the result, 21"${\times}$15.5" propeller was selected whose efficiency is 66% at cruise condition.

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Feasibility Study for Practical Application of Aerospace Derivative Technology - Vertical Wind Tunnel (항공우주 파생기술 실용화를 위한 타당성 연구 - 수직 풍동)

  • Kwon, Kijung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.2
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    • pp.148-153
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    • 2017
  • KARI LSWT(Korea Aerospace Research Institute Low Speed Wind Tunnel) has accumulated close to 20 years of know-how since its completion in 1998 and is trying to commercialize related technologies. As part of this research, KARI LSWT is studying design of vertical wind tunnel equipped with a skydiving simulator. KARI carries out concept design together with high performance/low noise design and is to transfer the related technology to a domestic producible company to increase commercialization possibility. In addition, KARI is seeking cooperation with related organizations in China to enter Chinese market.

Scaled effect correction method for the wind turbine blade with multi airfoils (다수의 익형이 적용된 풍력터빈 블레이드에 대한 축소효과 보상기법)

  • Jo, Tae-Hwan;Kim, Cheol-Wan
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.494-497
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    • 2009
  • 풍력터빈 블레이드 풍동시험의 경우 사용가능한 시험설비의 크기제한으로 인해 축소모델 사용이 불가피하며, 이로 인해 풍동시험에서는 실물 블레이드에 비해 10% 미만의 낮은 Re수에서 시험이 수행된다. 축소모델 블레이드 풍동시험 결과를 활용하여 실물 블레이드의 성능(토크)를 추정하기 위한 축소효과 보정기법을 2008년 제시하였으며, NREL Phase VI 모델 시험결과에 적용하였다. 당시 제시된 보정기법은 단일익형을 전체 블레이드에 사용한 사례이며 축소효과 보정을 위해 Re수에 따른 익형의 양력계수 변화만을 적용하였다. 본 논문에서는 당시 제안된 축소효과 보정기법을 익형의 양력계수 및 항력계수를 포함한 형태로 수정하였으며, 블레이드에 다수의 익형이 사용되었을 경우에 대해 확장하였다. NREL Phase VI 12% 시험모델의 경우 익형의 양력계수 기울기에 의한 보정량은 약 15% 정도이며, 항력계수 변화에 의한 보정량은 약 5% 정도로 나타났다. 블레이드에 다수의 익형이 사용되었을 경우 설계 또는 전산해석을 통해 구한 반경별 토크 함수를 적용하여 블레이드 축소효과를 보정할 수 있다.

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Effective Perceived Noise Level Prediction for a Propeller driven UAV by using Wind Tunnel Test Data (풍동실험결과를 이용한 프로펠러 무인 항공기의 환경인증소음 예측에 관한 연구)

  • Ryi, Jae-Ha;Rhee, Wook;Choi, Jong-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.1
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    • pp.10-16
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    • 2013
  • This paper discussed a procedure for noise certification of Aircraft and predicting the full scale over-flight noise of propeller from acoustic wind tunnel measurement of small scale propeller. Noise Certification Procedures is established from International Civil Aviation Organization(ICAO). The data manipulations are then discussed in extrapolation to simulation flight distance and flight simulation. One of the most important point of flight simulation is adjustments for differences between wind tunnel test conditions and flight test conditions. To simulated the noise level estimation procedure for noise data post-process, simulate procedures from data of the wind tunnel noise measurement and the flight noise measurement by using a 7kg degree UAV. This study confirmed an effectively noise estimation procedures by wind tunnel noise test and flight noise test.

A Study on Truncated Flapped Airfoil for Efficient Icing Wind Tunnel Test (효율적 결빙 시험을 위한 절단 익형 형상 연구)

  • Jung, Sung-Ki;Lee, Chang-Hoon;Nagdewe, Suryakant;Myong, Rho-Shin;Cho, Tae-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.6
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    • pp.481-486
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    • 2011
  • The evaluation of supercooled water droplet impingement characteristics of full-scale aircraft components in wind tunnels under icing conditions has been severely limited by the relative size of the component and the test facility. The concept of truncated airfoil sections has been suggested in order to extend the operational range of icing tunnels. With proper deflection of the small trailing-edge flap on the truncated airfoil the local pressure distribution may remain very close to that of the full-scale airfoil. In this study the shape of a truncated flapped airfoil is investigated for various deflection angles. To validate the truncated flapped airfoils, air flow and collection efficiency over the truncated airfoil are compared with the results of the full-scale airfoil obtained from the state-of-the-art icing simulation code.

Modificaion and Performance Test for improving ability of Supersonic/Hypersonic Wind Tunnel(MAF) (초음속/극초음속 풍동(MAF)의 성능 향상을 위한 개조 및 검증)

  • Choi, Won-Hyeok;Seo, Dong-Su;Lee, Jae-Woo;Byun, Yung-Hwan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.717-722
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    • 2010
  • Supersonic/Hypersonic wind tunnel is a facility which is intended to test and to observe the physical phenomena around a model by creating supersonic flow in the test section. In designing an airplane, the wind tunnel test is demanded to analyzing aerodynamic characteristics of the model without making a prototype. In this research, the model aerodynamic facility(MAF) is modified for the purpose of increasing running time and its functionality. New pneumatic valves for remote control was installed for safety requirement, and new air tanks was installed on MAF as well. A pipe system is also modified to use those new valves and tanks, and the ceiling and side glasses of the test section are switched to ones with the larger surface area. After the MAF modification, a test is performed at Mach 2, 3 and 4. In this test, shadow graph technique, one of the flow visualization methods, is used to visualize supersonic flow field. The pressure in the settling chamber and working section at Mach 2, 3 and 4 was measured in each case. As a result, the possible model size and running time are obtained.

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Development of wind power simulator using MATLAB SIMULINK (MATLAB_SIMULINK를 이용한 풍력 발전 시뮬레이터 개발)

  • Park, won-hyeon;Gebreslassie, Mihret;Park, Ji-Hyeon;Byun, Gi-Sik;Kim, Gwan-Hyung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.665-667
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    • 2016
  • Due to the depletion of fossil fuels and the environmental problems of recent years it has been increasing every year the interest in renewable energy. Renewable energy is clean and the typical method using solar and wind power and solar power as an energy source reusable. Wind power generation system of which it is a method of using the natural wind, convert the kinetic energy of the wind into electrical energy. Traditionally, implementing a wind power system, wind tunnel tests was to configure an environment similar to a real wind tunnel experiments. However, it costs a lot of money problems hagieneun configure these wind tunnel tests. Therefore, by this paper, in consideration of the fact, the characteristics of the generator in the wind tunnel experiment to experiment with such a wind tunnel test using a bad test by configuring the motor and controls the motor generator to obtain a result similar to the wind tunnel experiment.

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Validation for Performance and Hub Vibratory Load Analyses of Lift-offset Coaxial Rotors in Wind-Tunnel Tests (풍동 시험용 Lift-offset 동축 반전 로터에 대한 성능 및 허브 진동 하중 해석의 검증 연구)

  • Lee, Yu-Been;Park, Jae-Sang
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.7
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    • pp.497-505
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    • 2022
  • Performance and hub vibratory load analyses for a lift-offset coaxial rotor are conducted using a rotorcraft comprehensive analysis code, CAMRAD II. The lift-offset coaxial rotor is trimmed to match the total rotor thrust(lift-offset coaxial rotor's thrust) or the individual rotor thrust(upper and lower rotor thrusts, respectively) in this study. The individual rotor's lift and torque, and effective rotor lift to drag ratio for the total rotor are investigated for various advance ratios and lift-offset values. The two result sets with different trim methods are similar to each other and they are correlated well with the wind-tunnel test results. Therefore, the present study using CAMRAD II validates successfully the aeromechanics modeling and analysis techniques for the lift-offset coaxial rotor.

Aaerodynamic design of advanced concept car (고급개념 자동차의 공기역학설계)

  • 정인석;김현우
    • Journal of the korean Society of Automotive Engineers
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    • v.10 no.6
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    • pp.13-24
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    • 1988
  • 본 해설에서는 공기저항을 감소하기 위하여 위에서 열거한 점들을 고려한 공기역학적인 연구를 행함으로써 항력계수를 0.153까지 낮게한 Ford사의 프루우브IV 개발과 그 결과에 대하여 서술하고자 한다. 우선 일반적인 공기역학적 설계를 위한 연구에 대하여 서술하고 풍동실험을 반복한 결과로 보완된 부분에 대하여 설명한후 최종적인 차에 대한 풍동실험 결과를 서술하는 순서로 한다.

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Analysis on Heat Loss of Single-span Greenhouse Using Small-scaled Wind Tunnel (소형풍동을 이용한 단동 비닐온실의 열손실 분석)

  • Kim, Young Hwa;Kim, Hyung kow;Lee, Tae suk;Oh, Sung sik;Ryou, Young sun
    • Journal of Bio-Environment Control
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    • v.29 no.1
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    • pp.73-79
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    • 2020
  • The objective of this study is to analyze the heat transfer loss of covering materials in a single-span plastic greenhouse under the steady-state wind environment. To achieve this objective, the following were conducted: (1) design of a small-scaled wind tunnel (SCWT) to analyze heat losses of the greenhouse and its performance; (2) determination of the overall heat transfer coefficient (OHTC) for the covering materials using a small-scaled greenhouse model. The SCWT consists of the blowing, dispersion, steady flow, reduction and testing areas. Each part of the SCWT was customized and designed to maintain air flow at steady state and to minimize the variances in the SCWT test. In this study, the OHTCs of the covering materials were calculated by separating each with the roof, side wall, front and back of the small-scaled greenhouse model. The results of this study show that the OHTC of the roof increases as wind speed increases but the zones in which the increase rate of the OHTC decreased, were distinguished by wind tunnel wing speed of 2 ms-1. For the side wall, the increase rate of the OHTC was particularly higher in the 0-1 ms-1 zone.