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열선 질량유량계를 이용하여 측정한 열전달율이 큰 액체의 온도 특성에 관한 실험적 연구
윤준용(JoonYong Yoon),김효섭(HyoSeop Kim),김형준(HyoungJune Kim),성낙원(Nakwon Sung),이성규(SungKyu Lee) 한국유체기계학회 2007 유체기계 연구개발 발표회 논문집 Vol.- No.-
In this study, we classify the difference of heat transfer coefficient regarding to the temperature using thermal mass flowmeter. In using gas, the experiment condition regarding to temperature was generally ignored due to its characteristic of properties. In this experiment we focused on using water which properties(density, specific heat) are relatively high than gas to figure out the characteristic changes in terms of various conditions of temperature. The experiment was carried out at a certain range(20℃, 50℃ and 80℃). By changing the velocity of water at each temperature, the heat transfer coefficient was measured at 8자형 sensor which have separated RTD and heater. Throughout this study, we can analyze the characteristic curve between fluid and temperature and obtain specific experimental equation.
S-duct 흡입구 유로 형상 변화에 따른 엔진 입구면 유동 왜곡에 대한 정량적 평가
조낙원(Nakwon Jo),송지한(Jihan Song),윤준용(Joonyong Yoon) 한국추진공학회 2023 한국추진공학회 학술대회논문집 Vol.2023 No.5
This study aims to derive an S-duct shape suitable for a subsonic aircraft by quantitatively evaluating the flow distortion on the engine AIP(aerodynamic interface plane) according to the variation of the S-duct intake geometry. The S-duct is installed in front of the engine to supply stable air flow to the turbofan engine, but the airflow reaching the AIP cause flow distortion due to the S-duct shape. A severe distortion can cause engine surge. Therefore, precise evaluation of flow distortion is essential. In this study, a smooth S-duct shape is generated using an automated design algorithm and compared with the basic shape through 3D computational fluid dynamics. The flow distortion index at the AIP was evaluated using an automated evaluation tool that extract flow variables at a specific location using the same method as probe measurement for data consistency with experiments.
전달 물성 모델링 방법에 따른 압축기 전체 유로 수치해석
조낙원(Nakwon Jo),김상조(Sangjo Kim),윤준용(Joonyong Yoon) 한국추진공학회 2023 한국추진공학회 학술대회논문집 Vol.2023 No.5
Air within the compressor collides with blades rotating at high speeds, causing significant local pressure fluctuations. Generally, transport properties of gases such as specific heat, viscosity and thermal conductivity are sensitive to temperature change, and when the temperature changes significantly, they should be treated as temperature-dependent functions. However, temperature-dependent functions are sensitive to local variations in flow field, which can make convergence difficult and increase computational time. In this paper, the effect of modeling methods for transport properties on predicting the internal flow of the compressor is analyzed using 3D computational fluid dynamics tool, ANSYS CFX 2019R1 and confirms the convergence by applying temperature-dependet property models to full flow passage model of a 2 stage compressor.
김준형(Kim Joonhyung),최영석(Choi Youngseok),윤준용(Yoon Joonyong) 대한기계학회 2014 大韓機械學會論文集B Vol.38 No.2
본 논문은 해양플랜트용 다상유동 펌프 개발에 대한 주제로 연구를 수행한 내용이다. 연구 수행을 위하여 다상유동 펌프 임펠러와 디퓨져 기본 모델을 선정한 후 수치해석을 통한 성능 평가를 수행하였다. 실험 계획법(DOE)을 이용한 최적 설계를 수행하기 위해 임펠러와 디퓨져에 대한 설계 변수와 변수 변화 범위를 선정하였으며 선정된 변수들에 대한 시험 셋을 산출하여 수치해석을 통한 성능 평가를 수행하였다. 각 시험 셋에 대한 성능 평가 결과를 분석하여 설계 변수들에 대한 영향성 평가를 수행하였으며 최종적으로 다상유동 펌프에 대한 최적 모델을 도출하였다. 추가적으로 다상유동 해석을 수행하여 기체체적률(Gas Volume Fraction) 변화에 따른 성능을 평가하였다. A multiphase pump was developed in this study. The optimum multiphase pump design was arrived at, and the interactions among the different geometric configurations were explained by applying numerical analysis and the DOE (design of experiments) method. First, we designed the base model to meet the specifications. Then, we defined the design parameters related to the meridional plane and the blade angle. Each design parameter was used for generating experiment sets, and numerical analyses were performed on these sets. Finally, the optimized design was selected based on the results of the DOE analysis. The numerical optimization resulted in the optimum model having higher efficiency than the base model. In addition, performance degradation due to changes in the GVF (gas volume fraction) is discussed.