결빙 풍동 시험에서 벽면효과가 에어포일 결빙 증식에 미치는 영향에 관한 전산 해석

오승욱,장대익,배경훈,이원태,이학진,명노신 한국전산유체공학회 2023 한국전산유체공학회지 Vol.28 No.2

The icing on aircraft wings negatively impacts the aerodynamic characteristics of the aircraft, posing potential safety hazards. Accordingly, aircraft are equipped with anti-icing devices, the development of which requires accurate prediction of ice accretion and its range. Ice prediction methods are generally divided into two types: icing wind tunnel tests and icing simulations. While icing wind tunnel tests offer higher accuracy, they also incur considerable costs. This has led to the construction of smaller test sections, necessitating the consideration of wall effects. In this study, the Blockage Ratio was increased by reducing the height of the test wind tunnel, which allowed for the investigation of changes in ice accretion rate and shape. Wall-Airfoil interference was considered, leading to areas where water droplets did not collide, thereby impacting the shape of the ice. A three-dimensional airfoil model was designed, comparing a model with and without wall effects to understand differences in ice accretion on the airfoil. These analyses aided in the understanding of the impact of wall effects on ice wind tunnel tests and the accuracy of predictions.

회전익기 공기흡입구 주위 방빙장치 성능 해석

안국빈(Gook-Bin Ahn),정기영(Ki-Young Jung),정성기(Sung-Ki Jung),신훈범(Hun-Bum Shin),명노신(Rho-Shin Myong) 한국항공우주학회 2013 韓國航空宇宙學會誌 Vol.41 No.4

회전익기의 공기흡입구 주위 표면에 발생한 결빙은 엔진의 성능을 저해하는 요인으로 비행 안전성에 심각한 영향을 끼칠 수 있다. 항공기 표면에 발생하는 결빙현상을 분석하는데 많은 비용이 소요되는 결빙 풍동 시험 및 비행시험에 비해 전산유체역학을 기반으로한 결빙 시뮬레이션은 매우 효과적인 도구가 될 수 있다. 본 연구에서는 결빙조건에서 회전익기 공기흡입구 부근에 설치된 방빙장치의 작동 유무에 따른 결빙의 양과 발생 영역을 CFD 예측기법 및 결빙 풍동시험을 통해 분석하였다. 방빙장치를 작동시킨 경우 공기 흡입구 표면에서의 결빙의 질량과 최대 두께가 약 80% 이상 감소하는 것을 확인하였다. Ice accretions on the surface around a rotorcraft air intake can deteriorate the safety of rotorcraft due to the engine performance degradation. The computational simulation based on modern CFD methods can be considered extremely valuable in analyzing icing effects before exact but very expensive icing wind tunnel or in-flight tests are conducted. In this study the range and amount of ice on the surface of anti-icing equipment are investigated for heat-on and heat-off modes. It is demonstrated through the computational prediction and the icing wind tunnel test that the maximum mass and height of ice of heat-on mode are reduced about 80% in comparison with those of heat-off mode.

KC-100 항공기의 표면발생 Icing 형상 및 공력 영향성 연구

정성기(Sung-Ki Jung),이창훈(Chang-Hoon Lee),신성민(Sung-Min Shin),명노신(Rho-Shin Myong),조태환(Tae-Hwan Cho),정훈화(Hoon-Hwa Jeong),정재홍(Jae-Hong Jung) 한국항공우주학회 2010 韓國航空宇宙學會誌 Vol.38 No.6

비행 중 대기조건에 의한 결빙은 항공기 안전성과 직결되며, 특히 항공기 표면 발생 결빙은 공력 특성 변화를 야기하여 제어면 성능을 저해하는 요소가 된다. KC-100 항공기의 결빙에 의한 공력 영향성 조사를 위해 결빙 전문 CFD 코드인 FENSAP-ICE를 이용하였다. 항공기의 공력 특성을 대표하는 주날개 단면 익형을 먼저 고려하고 다음으로 전기체 형상에 대해 결빙 해석을 수행하였다. 또한 Anti-Icing 및 De-Icing 장치 설계를 위해 항공기 부품별 결빙 영역 및 결빙 증식 크기를 조사하였다. 결빙 영역은 주날개 및 수평 꼬리날개의 앞전에서 단면 코드길이 기준 약 7.07%, 11.2% 범위를 나타냈고, Wind Shield의 경우 약 16.7%에서 결빙이 발생하였다. 결빙에 의한 공력특성 변화의 경우, 받음각 0도에서 KC-100 항공기의 양력은 64.3% 감소한 반면 항력은 55.2% 증가하였다. In-flight icing is a critical technical issue for aircraft safety and, in particular, ice accretions on aircraft surfaces can drastically impair aerodynamic performances and control authority. In order to investigate icing effects on the aerodynamic characteristics of KC-100 aircraft, a state-of-the-art CFD code, FENSAP-ICE, was used. A main wing section and full configuration of KC-100 aircraft were considered for the icing analysis. Also, shapes of iced area were calculated for the design of anti-/de-icing devices. The iced areas around leading edge of main wing and horizontal tail wing were observed maximum 7.07% and 11.2% of the chord length of wing section, respectively. In case of wind shield, 16.7% of its area turned out to be covered by ice. The lift of KC-100 aircraft were decreased to 64.3%, while the drag was increased to 55.2%.

풍력 블레이드의 결빙에 의한 공력특성 및 성능 변화

박지호(Ji-Ho Park),명노신(Rho-Shin Myong) 한국항공우주학회 2014 韓國航空宇宙學會誌 Vol.42 No.2

추운 기후에서 운영되는 풍력터빈 시스템의 표면에 발생한 결빙으로 인하여 공기역학적 성능이 크게 저하될 수 있다. 이러한 결빙은 양력감소 및 항력증가를 야기하고, 발전효율에 부정적인 영향을 미치게 된다. 이로 인하여 풍력발전기의 성능저하 또는 과부하, 무게중심의 변화에 따른 과도진동, 결빙파편이 지상으로 떨어질 경우의 안전성 문제, 계기의 결빙으로 인한 계기 측정오차, 최악의 경우 풍력 시스템 정지 등의 문제가 발생한다. 본 연구에서는 결빙증식이 풍력 발전기의 공력특성에 미치는 영향을 CFD 기법을 이용해 분석하였다. 또한 결빙증식 결과를 바탕으로 BEM 기법을 적용시켜 삼차원 블레이드에 대한 공력성능을 계산하였다. 결빙의 두께는 상대적인 속도차이에 의해 블레이드 중심에서 끝단으로 갈수록 증가함을 알 수 있었고, 공기의 속도가 결빙증식에 미치는 주요 인자임을 확인하였다. A significant degradation in the aerodynamic performance of wind turbine system can occur by ice accretion on the surface of blades operated in cold climate. The ice accretion can result in performance loss, overloading due to delayed stall, excessive vibration associated with mass imbalance, ice shedding, instrumental measurement errors, and, in worst case, wind turbine system shutdown. In this study, the effects of ice accretions on the aerodynamic characteristics of wind turbine blade sections are investigated on the basis of modern CFD method. In addition, the computational results are used to predict the performance of three-dimensional wind turbine blade system through the blade element momentum method. It is shown that the thickness of ice accretion increases from the root to the tip and the effects of icing conditions such as relative wind velocity play significant role in the shape of ice accretion.

회전익기 공기흡입구의 표면발생 결빙에 관한 전산 예측

정기영(K.Y. Jung),안국빈(G.B. Ahn),명노신(R.S. Myong),조태환(T.H. Cho),정성기(S.K. Jung),신훈범(H.B. Shin) 한국전산유체공학회 2012 한국전산유체공학회지 Vol.17 No.2

Ice accretion on the surface of aircraft in flight can adversely affect the safety of aircraft. In particular, it can cause degradation of critical aircraft performances such as maximum lift coefficient and total pressure recovery factor in engine air intake. In this study, computational prediction of ice accretion around a rotorcraft air intake is conducted in order to identify the impingement region with high droplet collection efficiency. Then the amount of ice accretion on the air intake, which is essential in determining the required power of ice protection system, is calculated. Finally, the effect of icing wind tunnel size is investigated in order to check the compatibility with the real in-flight test environment.

결빙이 중형 수송기의 공력에 미치는 영향성에 관한 전산 해석

장대익,이혁진,정호진,이학진,명노신 한국전산유체공학회 2022 한국전산유체공학회지 Vol.27 No.3

When the aircraft flies through rain or clouds, supercooled water droplets or cloud particles cause aircraft icing by impinging on the surface of the aircraft. Accreted ice causes a change in the shape of the wing, negatively affects aerodynamic characteristics, and is a direct threat to safe flight. In this study, the effect of icing on the aerodynamic performance of medium-sized transport aircraft was analyzed by computational simulation. The iced area attached to the leading edge of the main wing and the tail wing was observed to be up to 5.3 cm. In addition, the reduction in aerodynamic performance was more considerable in the glaze ice condition due to the complicated geometry of ice. As a result of the study, the effect of icing on the lift and drag coefficient was investigated. The lift coefficient decreased by approximately 20% and the drag coefficient increased by approximately 70%. This suggests that icing will have a negative effect on the cruising range and endurance, which are important performances of medium-sized transport aircraft. In the future, this study can be extended to studies on the effects of ice accretion and design of ice protection systems.

결빙증식과 천이를 고려한 익형의 설계최적화

이현주,조창열 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11

결빙증식과 천이를 고려한 익형의 공력 설계최적화를 수행하였다. 익형의 형상은 NURBS 기반의 형상함수로 구현하였고, 공력특성은 RANS 방정식 기반의 FLUENT를 사용하여 해석하였다. 난류모델은 저레이놀즈수 k-ω SST 4 방정식 모델을 사용하였다. 결빙해석을 위해 FENSAP-ICE를 사용하였고, 반응표면법을 사용하여 전역최적화를 수행하였다. 본 최적설계과정은 천이와 결빙특성을 동시에 고려한 층류익형의 형상설계능력을 가지고 있음을 보여주었다. Design optimization of airfoils were performed considering ice-accretion and flow transition together. Airfoil shapes are designed using NURBS-based shape functions and aerodynamic characteristics of them are analyzed by a RANS-based CFD package FLUENT with the Low Reynolds number SST 4 equations turbulence model. Ice accretion on airfoils is analyzed by FENSAP-ICE. Response surface method is used to get global optima. Optimization results demonstrate successful design capability of the current procedure which considering flow transition and ice accretion characteristics.

CFD를 이용한 항공기 공기 흡입구 주위 결빙 예측

정기영(K.Y. Jung),안국빈(G.B. Ahn),정성기(S.K. Jung),명노신(R.S. Myong),조태환(T.H. Cho),신훈범(H.B. Shin),정주현(J.H. Jung),최영호(Y.H. Choi),김정훈(J.H. Kim) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5

Ice accretion on aircraft surface can greatly deteriorate the safety of aircraft. In particular, it can be a cause of impediment for aircraft performances such as aerodynamic characteristics, control, and engine. Numerical simulation of icing accretion based on the state-of-art CFD techniques can be alternative to expensive icing wind tunnel test or flight test. In this study, icing conditions are defined in order to predict the ice accretions around the air intake of aircraft. Then the range and amount of ice accretion on the intake in icing wind tunnel were investigated. In addition, a study on the size effect of icing wind tunnel was conducted in order to check the compatibility with the real in-flight test environment.

결빙이 정찰용 무인기의 공력에 미치는 영향성에 관한 전산 해석

이원태,장대익,배경훈,오승욱,이학진,명노신 한국전산유체공학회 2023 한국전산유체공학회지 Vol.28 No.2

When an aircraft encounters cloud layers with high humidity and sub-freezing temperatures, such as supercooled water droplets or ice particles, the aircraft's surface can undergo icing. Icing formation on an aircraft can lead to various issues, including reduced maximum lift coefficient, stall angle, and decreased controllability, which can potentially result in incidents and accidents. To prevent and mitigate these risks, the development of ice protection systems and research on icing phenomena are actively pursued worldwide. In this study, a three-dimensional compressible Reynolds-Averaged Navier-Stokes (RANS) equation was employed to perform computational analysis, focusing on investigating the impact of icing on reconnaissance UAVs. Additionally, a specialized computational fluid dynamics (CFD) analysis software, FENSAP-ICE, was utilized to predict the icing shapes. The icing conditions were determined based on the representative rime and glaze icing conditions specified in the continuous maximum (CM) conditions of FAR Appendix C by the Federal Aviation Administration (FAA). The exposure time for icing was set to 45 minutes. The findings of this study aim to be utilized in future icing certification for UAV development and the design of icing protection systems.

항공기 결빙 예측을 위한 Eulerian 기반 액적 충돌 및 결빙 증식 코드

정성기(S.K. Jung),명노신(R.S. Myong),조태환(T.H. Cho) 한국전산유체공학회 2010 한국전산유체공학회지 Vol.15 No.2

As a step toward accurate prediction of droplet impingement and ice accretion on aircraft, an Eulerian-based droplet impingement and ice accretion code for air flows around an airfoil containing water droplets is developed. A CFD solver based on the finite volume method was also developed to solve the clean airflow. The finite-volume-based approach for simulating droplet impingement on an airfoil was employed owing to its compatibility with the CFD solver and robustness. For ice accretion module, a simple model based on the control volume is combined with the droplet impingement module that provides the collection efficiency. To validate the present code, it is compared with NASA Glenn IRT (Icing Research Tunnel) experimental data and other well-known icing codes such as LEWICE and FENSAP-ICE. It is shown that the collection efficiency and shape of ice accretion are in good agreement with previous experimental and simulation results.