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풍동실험을 통한 능동위상배열레이더에서 다층레이돔에 작용하는 공기력과 풍압의 실험적 연구
임성환,강광희,최지호,이승호,권순덕,Yim, Sung-Hwan,Kang, Kwang-Hee,Choi, Ji-Ho,Lee, Seung-Ho,Kwon, Soon-Duck 한국군사과학기술학회 2014 한국군사과학기술학회지 Vol.17 No.1
In this paper, we investigated the sensitivity of aerostatic force coefficients of multi-layer radom in the various wind speeds. The test was conducted in KOCED Wind Tunnel Center in Chonbuk National University, and wind speeds were in the range from 5 m/s to 26 m/s in order to determine the Reynolds number independence. The test results of present multi-layer radom were not affected by the Reynolds number, The maximum positive pressure coefficient was found to be 1.08 at the center of the front of the plane in angle of attack of 0 degree, the maximum negative pressure coefficient was -2.03 at the upper right corner in angle of attack of 120 degree, while maximum drag coefficient was 1.11 in angle of attack of 180 degree.
임성환(Sung Hwan Yim),김흥태(Heung Tae Kim),강영식(Young Sik Kang),이승호(Seung Ho Lee),권순덕(Soon Duck Kwon) Korean Society for Precision Engineering 2017 한국정밀공학회지 Vol.34 No.9
In this study, we analyzed wind torque from aerostatic force coefficients of radar structures according to the Reynolds number. The test was conducted in the KOCED Wind Tunnel Center at Chonbuk University, and the wind tunnel test model was at 1:8 scale. Wind speeds were in the range of 5-26 m/s to determine Reynolds number independence. Test results of the present radar system were not impacted by the Reynolds number. Maximum drag coefficient was 1.43 under an angle of attack of 0 degrees and angle of the vehicle was 135 degrees, while maximum positive pressure coefficient was 1.21 at the side of plane in angle of attack of 0 degrees. Maximum negative pressure coefficient was -2.06 at the corner front of the plane at an angle of attack of 90 degrees. To verify wind torque in the wind tunnel test, a drive system was designed and manufactured. A wind speed of 26 m/s, the maximum average operating wind speed condition, was applied to validate the radar was driven normally. Results of this study may be used as an evaluation method for wind speed tests of radar systems and large structures that cannot be used for wind tunnel tests.
안상혁(Sang Hyeok Ahn),임성환(Sung Hwan Yim),박준우(Jun Woo Park),라영은(Young Eun Ra) Korean Society for Precision Engineering 2020 한국정밀공학회지 Vol.37 No.2
In this study, pyrolytic graphite was applied to overcome the conventional cooling system. Pyrolytic graphite is an anisotropic material with high thermal conductivity in the X-Y direction and low thermal conductivity in the Z direction. The advantage of high thermal conductivity in the plane direction is applied to improve the performance of the cooling capacity transceiver module housing made of aluminum. In comparison with the housing using the aluminum, the housing applied to the PGS plate shows a higher cooling performance on the average temperature of chips and the temperature variations by 2.79% and 49.98%. The heat dissipation performance was investigated according to the thickness of the PGS and the via the shape. When the factor of thickness in PGS plate was “0.375”, the average temperature of the chip was the lowest, and the temperature variation decreased due to increasing the factor of thickness in the PGS plate. In the case of the via shape, the “separation plate” showed the lowest average temperature of chips and the “plate” showed the lowest temperature variation.
이원혁(Won-Hyuk Lee),임성환(sung-Hwan Yim),강광희(Kwang-Hwe Kang),권호상(Ho-Sang Kwon) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
The Radar is to find the target with radiating signal and taking reflected signal. Commonly the automotive radar use higher frequency range than another radar. The conventional automotive radar detects the nearby obstacle. Currently being developed automotive radar has bigger size and high power than the existing automotive radar because of detection angle and angular resolution of high performance. Automotive radar needs size reduction to be mounted a car and thermal stability for the stable operation of the electronic component. Find the suitable structure for size reduction and thermal stability through changing structure inner radar and using numerical analysis.