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추진체계 가압용 압력용기의 기체배출특성 모델에 관한 연구
황유준(Yoojun Hwang),변정주(Jung Joo Byun),이주영(Ju Young Lee),김기언(Kiun Kim) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5
가압용 압력용기로부터 오리피스를 통해 기체가 배출되는 경우에 대하여 기체배출특성을 예측하기 위한 모델 개발에 대한 연구이다. 추진체계에 사용하기 적합한 압력용기에 대해 시험을 수행하여 대표적인 압력과 온도를 계측하였고, 압력용기 내부의 열전달에 대한 가정과 이에 대한 모델을 적용하여 시뮬레이션을 통해 압력과 온도를 예측하여 비교하였다. 그 결과 제안된 열전달 모델을 통해 계측된 압력과 온도와 유사한 예측 결과를 확인하였다. Developing a model was carried out to predict the characteristic of a pressure vessel from which the gas was vented through an orifice. An experimental test was conducted on a pressure vessel applicable to a propulsion system so that representative pressure and temperature were measured. Simulations were conducted with models using assumptions considering heat transfer inside the vessel, and the results were compared to those from the experiment. As a result, it was found out that a proposed heat transfer model was proper to predict pressure and temperature of the vented gas comparable to the measured data.
황유준(Yoojun Hwang),이주영(Ju Young Lee),구본웅(Bon Ung Koo),유정규(Jung Kyu Ryou) 한국추진공학회 2019 한국추진공학회 학술대회논문집 Vol.2019 No.5
추진체계 공급용 연료탱크의 압력 유지를 위해 구성된 가압 시스템의 특성을 예측하기 위한 모델 개발에 대한 연구이다. 연료를 소모하면서 연료탱크 내 연료 부피는 감소하고, 압력용기로부터 오리피스를 통해 기체를 공급하여 남은 공간을 가압하는 특징을 가진다. 연료탱크의 외부는 강제대류에 의한 열전달 조건이 주어진다. 연료탱크 내부의 열전달에 대한 가정과 이에 대한 모델을 적용하여 시뮬레이션을 통해 압력과 온도를 예측하였다. 계측 결과와의 비교를 통해 모델의 예측이 적절함을 확인하였다. Developing a model was carried out to predict the characteristic of a fuel tank that is pressurized for fuel supply to the propulsion system. The volume of the fuel in the tank decreases while the rest of the tank volume is filled with the gas supplied from a pressure vessel through an orifice. The outside of the fuel tank is exposed to a forced convective heat transfer condition. Simulations were conducted with models using assumptions considering heat transfer inside the fuel tank to predict pressure and temperature. It was found out that the proposed model was proper to predict the characteristic of the fuel tank pressurization. The validity of the modeling was confirmed through comparison with the measurement data.
황유준(Yoojun Hwang),강신형(Shin-Hyoung Kang) 한국유체기계학회 2011 유체기계 연구개발 발표회 논문집 Vol.2011 No.11
Three dimensional unsteady numerical calculations were performed to investigate unsteadiness of the tip leakage flow in an axial compressor. The first stage of the four-stage low-speed research axial compressor was examined. Since this compressor has a relatively large tip clearance, the unsteadiness of the tip leakage flow is induced. Through the results from the unsteady calculations, the process of the induced unsteady tip leakage flow was investigated. It was shown that the leakage flow that occurred at a rotor blade tip clearance affected the pressure distribution on the pressure side near the tip of the adjacent blade, thus caused the fluctuation of the pressure difference between the pressure side and suction side. Consequently, the unsteady tip leakage flow was induced at the adjacent rotor blade. The unsteady feature of the tip leakage flow was changed as the operating point was moved. The interface between the tip leakage flow and the main flow only affected the trailing edge region at the design point whereas the interface influenced up to the leading edge at the low flow rate point. As the flow rate decreased, additionally, it was seen that the vortex size of the tip leakage flow increased and the relatively large length scale disturbance occurred. On the other hand, using frequency analysis, it was shown that the unsteadiness was not associated with the rotor speed and was about 40% of the blade passing frequency. This feature was explained in the rotor relative frame of reference, and the frequency decreased as the flow rate decreased.