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Double Serpentine 노즐의 단면적과 비행조건 변화에 따른 UCAV의 플룸 유동장 및 IR 특성 연구
이유렬(Yu-Ryeol Lee),이지원(Ji-Won Lee),신창민(Chang-Min Shin),명노신(Rho-Shin Myong) 한국항공우주학회 2021 韓國航空宇宙學會誌 Vol.49 No.8
현대 전장의 탐지기술 발달로 인해 항공기의 생존성이 크게 위협받고 있다. 그중 적외선(IR) 추적 미사일은 항공기의 생존성에 큰 영향을 끼치며, 항공기 임무 성공률을 저하시키는 주된 요인이다. 항공기 생존성을 증가시키기 위하여 곡률을 추가한 형상 변형 노즐에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 항공기 생존성을 증가시키기 위한 형상 변형 노즐 중 Double Serpentine 노즐을 선정한 다음, 노즐의 최대 면적변화율의 위치 효과를 분석하였다. 노즐의 최대 면적변화율이 노즐의 추력과 출구의 평균 온도에 영향을 끼치는 것을 확인하였다. 또한 최대 면적변화율이 노즐 후방에 위치함에 따라 추력 페널티가 줄어드는 것을 확인하였다. The development of modern warfare detection technology is increasingly threatening the survivability of aircraft. Among them, IR-seeking missiles greatly affect the survivability of aircraft and are a main factor that reduces the success rate of aircraft missions. In order to increase aircraft survivability, studies on shape-modifying nozzles with added curvature are being actively conducted. In this study, we selected a double serpentine nozzle among shape-modifying nozzles to increase aircraft survivability. We then investigated the effects of the location of the maximum area change rate of the nozzle. It was confirmed that the location of the change rate of area affects the thrust and exit temperature of the nozzle. In addition, it was shown that the thrust penalty was reduced as the position of the change rate of the maximum area was located at the rear of the nozzle.
고체/액체 혼합 입자 분사에 의한 항공기 노즐의 다상 유동에 관한 전산 해석
류석희,이유렬,신창민,명노신 한국전산유체공학회 2022 한국전산유체공학회지 Vol.27 No.3
Infrared (IR) signals from the hot exhaust gases of aircraft engines have a significant impact on the survivability of aircraft. Several methods were developed to reduce IR signatures to avoid tracking by IR signatures generated in the exhaust, or decoy flares are used to deceive IR seekers. Research into injecting water particles to lower the exhaust gas temperature or injecting carbon particles to shield the plume has also been previously conducted. In this study, we propose a method for injecting solid/liquid mixed particles that lower the exhaust gas temperature and block IR signal propagation generated in the exhaust gas. The multiphase flow in aircraft nozzles by solid/liquid mixed particle injection was analyzed using the CFD code for the total flow rate of particles corresponding to 5%, 10%, and 20% of the exhaust gas flow rate. After analyzing the characteristics of the mixed particles interacting with the exhaust plume, the optimal flow rate of water and carbon particles with a small thrust penalty was obtained.
비행 조건에서의 입자 분사에 따른 엔진 배기플룸 냉각 및 차폐 영향성 연구
신창민(C.M. Shin),이유렬(Y.Y. Lee),김재원(J.W. Kim),명노신(R.S. Myong) 한국전산유체공학회 2021 한국전산유체공학회지 Vol.26 No.3
Cooling and shielding effects of injecting micro-scale particles into the exhaust plume of an aircraft engine flying at high speed at an altitude of 6,096 m (=20,000 ft) were studied using computational methods. A discrete phase model was used to calculate a multiphase flow composed of exhaust plume and particles (liquid water mist and solid carbon). The IR radiation of the plume incident on the particle layer was first calculated, and then the radiation absorption coefficient of the injected particles was calculated using the discrete ordinate model. Furthermore, the change of the thermal flowfield of the exhaust plume according to the particle injection flow rate and the injection material, and the cooling and shielding effects were analyzed. The transmittance of the exhaust plume IR signal passing through the particle layer was determined through the maximum absorption coefficient at each point.
물 분사기법 적용에 따른 항공기 노즐의 유동 특성 해석
이지원(J.W. Lee),이유렬(Y.Y. Lee),김재원(J.W. Kim),명노신(R.S. Myong) 한국전산유체공학회 2020 한국전산유체공학회지 Vol.25 No.3
Modern weapon systems require stealth technology to avoid detection by enemy and successfully carry out missions. Among them, IR stealth technology, which increases the success rate of the mission by reducing IR signals, has been studied in various methods, and in particular, the particle injection techniques can effectively reduce IR signals through shielding and cooling effects. In this study, the characteristics of flow and particles by injecting water mist were analyzed to study the feasibility of injection techniques for reducing aircraft plume IR signals. The water spray was simulated by applying a multiphase fluid model, the discrete phase model (DPM) method, and the characteristics and temperature changes according to the flow rate were studied. We first investigated the effects of water mist, and then selected the amount of water mist that minimizes the change of the thrust line, and finally checked the change in the flow field due to the behavior and evaporation of water droplets.