http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
쌍롤 연속 주조에서의 난류 유동, 온도 및 응고 예측을 위한 연구
하만영,최봉석,Ha, Man Yeong,Choi, Bong Seok 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.1
A computer program has been developed for analyzing the two-dimensional, unsteady conservation equations for transport phenomena in the molten region of twin-roll continuous casting in order to predict the turbulent velocity, temperature fields, and solidification process of the molten steel. The energy equation of the cooling roll is solved simultaneously with the conservation equations of molten steel in order to consider heat transfer through the cooling roll. The results show the velocity, temperature and solidification pattern in the molten region with roll temperature as a function of time. The results for velocity and temperature fields with solidification are compared with those without solidification, giving different thermofluid characteristics in the molten region. We also investigated the effects of revolutional speed of roll, superheat and nozzle geometry on the turbulent flow, temperature and solidification in the molten steel and temperature fields in the cooling roll.
파울링 예측을 위한 가스-입자 이상 유동 해석(1)-고온 풍동 설계 및 성능실험-
하만영,이대래,Ha, Man-Yeong,Lee, Dae-Rae 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.11
We designed the hot wind tunnel to reproduce the conditions of utility boiler and carried out its performance test, in order to investigate the particulate two-phase flow behaviour, the fouling and heat transfer characteristics to the heat exchanger. The hot wind tunnel introduces the control system to control the temperature in the test section. The particle is injected into the hot gas stream. The fouling probe (cylindrical tube) is positioned normal to the particulate gas-particle two-phase flow and cooled by the air. The temperature of gas and cooling air, and temperature in the fouling probe are measured as a function of time, giving the local and averaged heat transfer and fouling factor. The shape of particulate deposition adhered to the fouling probe is also observed.
진동하는 유동장하에서 내부 순환 유동을 고려한 액적의 증발에 관한 수치적 연구
하만영,Ha, Man-Yeong 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.5
The two-dimensional, unsteady, laminar conservation equations for mass, momentum, energy and species transport in the gas phase and mass, momentum and energy in the liquid phase are solved simultaneously in spherical coordinates in order to study heating and vaporization of a droplet entrained in the oscillating flow. The numerical solution gives the velocity and temperature distribution in both gas and liquid phase as a function of time. When the gas flow oscillates around an vaporizing droplet, the liquid flow circulates in the clockwise or counterclockwise direction and the temperature distribution in the liquid phase changes its shapes, depending on the gas fow direction. When the gas flow changes its direction of circulating liquid flow is opposite to the gas flow, forming two vortex circulating in the opposite direction. During the heating period, the difference in the maximum and minimum temperature is large, followed by the almost uniform temperature slightly below the boiling temperature. The mass and heat transfer from the droplet depend on the droplet temperature, droplet diameter and the magnitude of relative velocity, giving the droplet lifetime different from the d$^{2}$-law.
평면형 및 확대형 정전분리기의 정전분리 특성에 대한 수치해석
하만영(Man-Yeong Ha),송하두(Ha-Doo Song),최두성(Doo-Sung Choi) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5
In the present study, we investigated the factors to have an effect on the efficiency of electrostatic separator and carried out the numerical simulation under the variation of these factors to obtain the parameters for the optimal design of electrostatic separator. We applied the RANS (Reynolds-Averaged Navier Stokes) analysis in order to obtain the important parameters for the electrostatic separator design. Also we compared the three-dimensional flow analysis for the parallel and diffuse type of the electrostatic separator with using the experimental study. We developed the computer program to solve the particle trajectories under the influence of drag, gravity and electrostatic forces in the Lagrangian framework, using the flow fields obtained from RANS calculation. We considered the effects of particle size, particle charging quantity, applied voltage between plates and inlet flow velocity on the particle trajectories and attachment on the plate.
수직 평판에 설치된 경사 핀-휜의 혼합대류 열전달 특성에 대한 수치적 연구
오영웅(Yeong Woong Oh),최윤석(Yoon Suk Choi),하만영(Man Yeong Ha),민준기(June Kee Min) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
The heat transfer of slanted-pin fins mounted on a vertical heated wall under laminar mixed convection condition has been investigated numerically, which is an extended study of the authors previous research on the natural convection [5]. Assuming the air is the ideal gas, three-dimensional governing equations of flow and heat transfer was solved using the periodic boundary condition in the horizontal lateral direction with the SIMPLE algorithm. The radiation heat transfer was calculated by using the discrete ordinate method to make sure the validation through a comparison with the experimental data. The effects of the fin-inclination angle were conducted in a modified Richardson number range of 500 - 2500 by varying the Reynolds number at a fixed Grashof number under constant heat flux conditions. As the forced convection increases, the advantageous fin-inclination angle having the best heat transfer capability became from negative to positive fin angles. The critical Richardson number showing this transition phenomena and corresponding characteristics of flow and heat-transfer are summarized.
대형 와 모사를 통한 레이놀즈 수 증가에 따른 혼합 탱크 내의 유동 구조의 연구
윤현식,전호환,하만영,Yoon, Hyun-Sik,Chun, Ho-Hwan,Ha, Man-Yeong 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.9
The stirred tank reactor is one of the most commonly used devices in industry for achieving mixing and reaction. Here we report on results obtained from the large eddy simulations of flow inside the tank performed using a spectral multi-domain technique. The computations were driven by specifying the impeller-induced flow at the blade tip radius. Stereoscopic PlY measurements (Hill et al. $^{(1)}$) along with the theoretical model of the impeller-induced flow (Yoon et al. $^{(2)}$) were used in defining the impeller-induced flow as superposition of circumferential, jet and tip vortex pair components. Large eddy simulation of flow in a stirred tank was carried out for the three different Reynolds numbers of 4000, 16000 and 64000. The effect of different Reynolds numbers is well observed in both instantaneous and time averaged flow fields. The instantaneous and mean vortex structures are identified by plotting an isosurfaces of swirling strength for all Reynolds numbers. The Reynolds number dependency of the non-dimensional eddy viscosity, resolved scale and subgrid scale dissipations is clearly shown in this study.