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비정상열유속 기법을 이용한 표면 열유속 해석에 관한 연구
이종주,Yi, Jong-Ju 한국군사과학기술학회 2010 한국군사과학기술학회지 Vol.13 No.3
The quick variation of the canister wall temperature causes the modification of the shape of canister wall. This paper is the possibility of adoption and the error analysis about the transient heat flux method. The commercial code(Fluent Ver6.2.16) was employed for the calculation of surface temperature in the case of steady and unsteady heat flux condition. Based the surface temperature variation and surface material property, transient heat flux method can calculate the surface heat flux. In the case of steady heat flux condition, the error is about 2%, and in the case of unsteady heat flux condition, the error is about 3.6%. With the unsteady heat flux condition, the time which reach the maximum surface heat flux is almost same between the numerical analysis and transient heat flux method.
선형펌프방식 압축수 시스템의 실험적 수중소음인자별 경향분석 연구
이종주,안강수,서종무,Yi, Jong-ju,Ahn, Kang-su,Sur, Jong-mu 한국군사과학기술학회 2021 한국군사과학기술학회지 Vol.24 No.2
In order to understand the underwater noise source factor of the linear pump type forced ejection system, a reduced-model compressed water experiment device was developed. The reduced-model compressed water experiment device consists of a reverberation tank, a linear pump type forced ejection device, and an underwater vehicle. The underwater noise source was selected from the hydraulic ram moving speed, the hydraulic ram/piston pipe spacing, the ejection pipe inlet/water ram area ratio, and the number of water ram inlets. The underwater vehicle was ejected into the reverberation tank by the device. The source level was derived from the measured sound pressure. The source level tends to increase as the hydraulic ram/piston tube spacing and the hydraulic ram moving speed increase. The source level tended to increase as the area ratio was increased, but the level was weak. The number of water ram inlet did not affect the source level.
이종주,김좌일,김재호,함일배,Yi, Jong-Ju,Kim, Chwa-Il,Kim, Jae-Ho,Ham, Il-Bae 한국군사과학기술학회 2012 한국군사과학기술학회지 Vol.15 No.4
This paper describes about the analysis of firing rebounding force exerted on the launching system supporting structure. The measured high pressure data at the launching tube is used as external force. The maximum firing rebounding force was occurred when the snubber of inner structure contacts the surface of wall in launching tube.
선체진동신호를 이용한 3차원 수중방사소음 패턴 산출에 대한 수치해석 연구
이종주(Jong-Ju Yi),강명환(Myung-Hwan Kang),한승진(Seung-Jin Han),배수룡(Soo-Ryong Bae),김재호(Jae-Ho Kim),정우진(Woo-Jin Jung) 한국소음진동공학회 2014 한국소음진동공학회 논문집 Vol.24 No.10
In this study, a numerical estimation method for 3D underwater radiated noise pattern using hull vibration and total acoustic power of the vibrating structure in the far-field is proposed. The underwater radiated noise pattern is known to be predicted using the vibration signals and radiation efficiency of each surface patch. But it is very difficult to know radiation efficiency of each surface patch which is one of important factors to calculate the 3D underwater radiated noise pattern. Instead of using radiation efficiency of each patch, the underwater radiated noise level is modified with the total acoustic power of the vibrating structure. The suggested estimation method for underwater radiated noise pattern is discussed with numerical model.
원형 캐비테이터의 받음각에 따른 환기초공동 형상 예측 연구
이종주(Jong-Ju Yi),김민재(Min-Jae Kim),백부근(Bu-Geun Paik),김경천(Kyung Chun Kim) 한국가시화정보학회 2021 한국가시화정보학회지 Vol.19 No.3
Ventilated cavity shapes by varying angle of attack of a circular cavitator were predicted based on Logvinovich’s Independence Principle in order to verify the cavity shape prediction method. The prediction results were compared with model experiments conducted in the high-speed cavitation tunnel. In the prediction of the cavity centerline, the movement of the cavity centerline due to the effect of gravity and cavitator’s angle of attack were well predicted. In the prediction of the cavity contour, it was found that the cavity edge prediction error increased as the angle of attack increased. The error of the upper cavity contour was small at the positive angle of attack, and the error of the lower cavity contour was small at the negative angle of attack.
초음속 유동장내 2차분사 분사각도 변화에 따른 열전달 특성 변화
송지운(Jiwoon Song),이종주(Jong Ju Yi),조형희(Hyung Hee Cho),배주찬(Ju Chan Bae) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.11
초음속 유동장내에 분사된 2차제트 주변에서의 열전달 현상을 고찰 하였다. 초음속 유동장내에 분사되는 2차유동의 Jet to freestream momentum ratio(운동량비)의 변화와, 2차유동 분사각도에 따른 2차 분사홀 주변의 열전달 특성을 파악하기 위하여 홀 주변의 표면온도 변화를 고속 적외선 카메라를 통하여 측정하였으며, 이를 이용하여 비정상 열유속 기법을 바탕으로 열유속을 계산하였다. 운동량비가 증가할 수록 열전달 현상이 강화 되었으며, 15˚ 기울어진 분사보다는 수직 분사의 경우에 더 강한 열전달 현상이 발생되었다. 이를 통해 분사비와 분사 각도가 표면 열전달 분포에 중요한 요인으로 작용함을 확인할 수 있었다. In this paper, heat transfer changes due to the shock/boundary layer interaction were investigated on surfaces where secondary jet are injected. With an infra-red thermography, surface temperature was measured and the measured data was used to obtain the convective heat transfer. Heat transfer is enhanced with increment of momentum ratio. And normal injection case has a higher heat transfer value than that of 15 degrees inclined injection case. Secondary injection momentum ratio and injection angle affect the surface heat transfer distribution.