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해인사 장경판전 주변 건축물 이건에 따른 장경판전 환기 기류 변화 해석
허남건,이명성,양성진 대한설비공학회 2007 설비공학 논문집 Vol.19 No.5
In the present study, ventilation flow in the Janggyeongpan-Jeon at Haein temple in case of building rearrangement has been investigated numerically. To achieve more accurate results, detailed shapes such as buildings and the window grills are modeled and tree canopy model is adopted to account for the effect of trees in the computation. Wind velocities as boundary condition are taken from meteorological statistical data. The numerical results show that ventilation flow distributions at Janggyeongpan-Jeon in case of building rearrangement are nearly similar to those before rearrangement.
Numerical flow analyses of a two-phase hydraulic coupling
허남건,곽민희,M. Moshfeghi,Choon-Soo Chang,N.-W. Kang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5
We investigated flow characteristics in a hydraulic coupling at different charged water conditions and speed ratios. Hence, simulations were performed for three-dimensional two-phase flow by using the VOF method. The realizable k-ε turbulence model was adopted. To resolve the interaction of passing blades of the primary and secondary wheels, simulations were conducted in the unsteady framework using a sliding grid technique. The results show that the water-air distribution inside the wheel is strongly dependent upon both amount of charged water and speed ratio. Generally, air is accumulated in the center of the wheel, forming a toroidal shape wrapped by the circulating water. The results also show that at high speed ratios, the solid-body-like rotation causes dry areas on the periphery of the wheels and, hence, considerably decreases the circulating flow rate and the transmitted torque. Furthermore, the momentum transfer was investigated through the concept of a mass flux triangle based on the local velocity multiplied by the local mixture density instead of the velocity triangle commonly used in a single-phase turbomachine analysis. Also, the mass fluxes along the radius of the coupling in the partially charged and fully charged cases were found to be completely different. It is shown that the flow rate at the interfacial plane and also the transmitted torque are closely related and are strongly dependent upon both the amount of charged water and speed ratio. Finally, a conceptual categorization together with two comprehensive maps was provided for the torque transmission and also circulating flow rates. These two maps in turn exhibit valuable engineering information and can serve as bases for an optimal design of a hydraulic coupling.
허남건,이명성,양성진 대한설비공학회 2011 International Journal Of Air-Conditioning and Refr Vol.19 No.4
Haeinsa temple is famous for over 80 000 wooden printing blocks of Buddhist scriptures called Tripitaka Koreana and its storage halls, both of which have been registered as the world cultural heritages by UNESCO. The objective of the present paper is to investigate the ventilation flow in the storage halls of Tripitaka Koreana in the case of building rearrangement in Haeinsa temple. Three-dimensional flow simulations were performed with the detailed geometry of all buildings in the temple. The slatted windows on walls of the storage halls and Tripitaka Koreana stored in the shelves inside the storage halls were modeled in detail to predict reliable ventilation performance. A tree canopy model was also adopted to take into account of the effect of the forest surrounding the temple. Wind velocities as inlet boundary condition were imposed from meteorological statistical data. The numerical results were obtained for the effects of the wind direction, wind speed and tree canopy model on the ventilation performance of the storage halls. It was shown from the numerical results that the ventilation flow distribution at the storage halls in the case of building rearrangement would not be significantly altered compared to that before rearrangement.
일반 비직교좌표계를 사용하는 3차원 범용 유동해석 프로그램의 개발
허남건,조원국,김광호 대한기계학회 1994 대한기계학회논문집 Vol.18 No.12
A general purpose program, TURBO-3D, for the analysis of 3-D fluid flow in complex geometry has been developed, which employs a standard $k-\varepsilon$ turbulence model and a general nonorthogonal grid system. For the purpose of verification of the program and testing the applicability, turbulent flows in an S-shaped diffuser and turbulent flows over an backward facing step are solved and compared with the earlier results. Comparison with the results by the STAR-CD program has been also made for the same flow configuration and grid structure. The agreements are excellent and hence the program has been verified. Since the present program is applicable only on limited flow phenomena and lacks the pre-and post processor, further improvements toward these directions are being made.