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시로코 환기팬 블레이드 설계 변수에 따른 유동 및 소음 특성에 대한 수치 해석 연구
전유선,남현택,김진택,이철형,선광명,이승로 한국기계기술학회 2021 한국기계기술학회지 Vol.23 No.4
Numerical analysis for flow and noise characteristics of sirocco fan design factors is conducted in this study. 4 cases of blade angle(α=24°~30°) and 5 cases of RPM(390~1170RPM) are calculated. Flow characteristics are compared for the number of blades. Outlet flow rate is tended to decrease as the number of blades increased. There is little difference in the flow characteristics for the angle of blade. The highest outlet flow rate is predicted at α=24°, and the lowest at α=28°. Flow and noise characteristics are compared for α=24° and 26°. Outlet flow rate is almost similar in both cases, but noise for α=24° is predicted higher at high RPM conditions.
저소음형 축류 팬 개발을 위한 수치해석 연구PartⅠ : 팬 내부의 유동 구조 및 소음원 분석
전유선,남현택,김진택,이철형,선광명,이승로 한국기계기술학회 2020 한국기계기술학회지 Vol.22 No.2
In this study, numerical analysis was carried out to develop low-noise axial fans, which are often used for ventilation in houses. A commercial program and the turbulence models are used for the analysis of internal fan. Proudman acoustic power model and the Curle surface acoustic power model were used for analysis. As a result, the distribution of flow velocity and pressure around the blade and guide of the fan was high, and low in the center of the fan. Noise from the inner wall of the fan case and the blade surface was the highest at the body and vane connections of the blade, and low at the center of the vane and the center of the body.
SiO2 나노유체에서 관의 형상에 따른 열전달 특성에 관한 수치해석 연구
전유선,남현택,김종현,이승로 한국기계기술학회 2020 한국기계기술학회지 Vol.22 No.4
In this paper, the heat transfer performance of nanofluids is predicted by numerical analysis methods. The nanoparticles used in this study is SiO2, with concentrations of 1, 2, 3vol.%, and the base fluid is water. Reynolds number of nanofluids ranges from 10,000 to 50,000. A numerical study on the heat transfer characteristics of nanofluid was conducted using a single-phase model. The temperature of the fluid entering from the inlet of the tube is 293.15K. A constant heat flux of 31,650W/m2 was applied at the wall, and the thickness of the wall was ignored. Heat transfer coefficients, thermal conductivity and Nusselt number were selected as indicators for comparing heat transfer performance of nanofluids. As the nanofluid concentration increases, the temperature and velocity distribution by the cross section of the coil tube and straight tube increased. As the Reynolds number increases, temperature difference between inner direction and outer direction reduced in coil tube. For straight tube, the temperature difference between the wall and the center of the tube also decreased.
중학교 과학 교과서 물질 단원에 제시된 시각적 입자 표상의 활용 방식 분석
전유선,김성훈,노태희,강석진 대한화학회 2023 대한화학회지 Vol.67 No.5
This study analyzed the uses of visual representations of particles in the matter units of the middle school science textbooks developed under the 2015 Revised National Curriculum. The material units in four textbooks were divided into explanation, inquiry, and evaluation sections, and visual representations of particles presented in the science textbooks were analyzed by the use type, the activity type, and the level of activity. In the explanation section, the visual representations of particles were mainly presented in the auxiliary use type, and in the inquiry and evaluation section, they were mainly presented in a direct use type. In terms of the activity types of the direct use of visual representations of particles, the interpreting activity was mainly presented in the explanation and evaluation sections, while the generating activity and completing activity were presented in relatively higher proportion in the inquiry section than the other two sections. In terms of activity level, identifying was the most common activity level in the explanation section, and inferring was the most common activity level in the inquiry and evaluation sections. Based on these results, the implications for the presentation and uses of visual representations of particles in science textbooks are discussed.