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직교류 홴의 유동 해석: 깃 형상 변화가 성능에 미치는 영향
허남건,김욱,강신형,Hur, Nahm-Keon,Kim, Wook,Kang, Shin-Hyoung 한국유체기계학회 1999 한국유체기계학회 논문집 Vol.2 No.1
Cross flow fans are used in various applications, especially in industrial ventilation applications and in room air conditioners, due to their superior performance characteristics. Unlike radial and/or axial fans, the design of cross flow fans have been mostly based on earlier experiences and experiments. In the present study, numerical computations of flow fields through a cross flow fan used in room air conditioner are performed to investigate the detailed flow fields and to study the effect of the blade shape on performance curves to aid better design of the fan. Despite some discrepancies between the two results, it is seen from the present study that the computational results agree quite well with the qualitative experimental results. It is also shown from the present study that by having a different shape of blade, it is possible to achieve about $15\%$ increase in flow rates. The stimulating results of the present study can be used in the design of high performance cross flow fans with the use of optimal design algorithm and experimental verifications.
허남건,원찬식,Hur, Nahm-Keon,Won, Chan-Shik 한국유체기계학회 1999 한국유체기계학회 논문집 Vol.2 No.1
Transient flow inside a hollow shaft of a Gas Turbine engine during sudden engine stop may result in non uniform heat transfer coefficients in the shaft due to flow instability similar to steady Taylor vortex, which may decrease the lifetime of the shaft. In the present study, transient Taylor vortex phenomena inside a suddenly stopped hollow shaft are studied analytically. Flow visualization is also performed to study the shape and onset time of Taylor Vortices for various initial rotational speed.
원자로 냉각재 펌프의 과도 상태의 유동 및 열전달 해석 연구
허남건,김성원,유기풍,김승태,Hur, N.,Kim, S.,Yoo, K.-P.,Kim, S. T. 한국유체기계학회 2000 한국유체기계학회 논문집 Vol.3 No.2
The structural analysis of a reactor coolant pump(RCP) of a nuclear power plant is very important for the safety assessment of the plant. Accurate boundary conditions for the heat transfer coefficient are required for reliable thermal stress analysis of the pump casing, especially in transient operations of the pump since the coolant properties are largely dependent on operational conditions. In the present study, a 3D mixed flow type coolant pump was modeled from the RCP drawings and analyzed in the steady state and number of transient flow conditions by using a commercial code STAR-CD. From the result of the computation, it is seen that the average heat transfer coefficients for the cases considered are found to be the suggested values of the manufacturer, Westinghouse Energy System. The unevenness in local heat transfer coefficients, however, is found to be considerable so that the use of average heat transfer coefficients in all boundaries might not give reliable thermal stress predictions.
허남건,김욱,김사량,차철현,Hur, Nahm-Keon,Kim, Wook,Kim, Sa-Ryang,Cha, Chul-Hyun 대한설비공학회 2001 설비공학 논문집 Vol.13 No.6
In the present study, the transient axi-symmetric numerical simulation of traffic ventilation induced by a train running through a 15.6km-long tunnel is performed by using over 100,000 computational cells. With train running, three cases of ventilation schemes are simulated, which are the case of ventilation fans turned on, the case of no fan but ventilation shafts open, and the case of no fan and no shaft. Results of the ventilation flow rate are pressure transients are compared for the cases considered.
거리-시간 측정에 의한 고정도 타행시험법: Ⅰ.관련이론 및 정밀도 향상방법 고찰
허남건(N.Hur),안이기(I.K.Ahn) 한국자동차공학회 1994 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
A coast down test method has been used to determine the resistance forces on running vehicle due to the aerodynamic drag, rolling resistance and driveline resistance. Most of the tests. however. are the tests based on the Velocity-Time measurements.<br/> which require a sophisticated velocity measuring device and contains much error by nature. In the present study a coast down test method based on Distance-Time measurements is introduced, which contains the original idea of Russian scientist Prof. Petrushov along with the suggestions for improvement of the accuracy.<br/>
허남건(Nahmkeon Hur),원찬식(Chan-Shik Won),유홍선(Hong-Sun Ryou),손기헌(Gihun Son),김사량(Sa Ryang Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
A general purpose CFD program NUFLEX has been developed, which is capable of analyzing laminar/turbulent flows in complex geometries with various physics models. The flow physics implemented in the program include internal tracking, cavitation, melting/solidification, spray, etc. In the present paper, a brief introduction of the program will go given and some application of the program will be demonstrated.
다중현상 유동 해석 및 설계를 위한 융복합 프레임웍 개발
허남건(Nahmkeon Hur) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
Recently, the rapid evolution of computational fluid dynamics (CFD) has enabled its key role in industries and predictive sciences. From diverse research disciplines, however, are there strong needs for integrated analytical tools for multi-phenomena beyond simple flow simulation. Based on the concurrent simulation of multi-dynamics, multi-physis and multi-scale phenomena, the multi-phenomena CFD technology enables us to perform the flow simulation for integrated and complex systems. From the multi-phenomena CFD analysis, the high-precision analytical and predictive capacity can enhance the fast development of industrial technologies. It is also expected to further enhance the applicability of the simulation technique to medical and bio technology, new and renewable energy, nanotechnology, and scientific computing, among others.
사각 공동구의 하부 벽면 가진의 진폭 변화에 따른 자연 대류 유동의 공진 현상에 관한 연구
허남건(N. Hur),김욱(W. Kim),김영규(Y. Kim),강병하(B. H. Kang) 한국전산유체공학회 2000 한국전산유체공학회 학술대회논문집 Vol.2000 No.10
In the present study a numerical simulation is performed on a natural convection inside a square cavity with a vibrating bottom wall. The heat transfer coefficients for various amplitudes of the bottom wall vibration were compared to the case without the bottom wall excitation. From the results, it is seen that the local temperature distribution in a cavity becomes more uniform as the amplitude of the bottom wall vibration is increased. Also, it was seen that the heat transfer coefficient increased on the heating wall as the applied amplitude increased.
허남건(Nahmkeon Hur),원찬식(Chan-Shik Won),유홍선(Hong-Sun Ryou),손기헌(Gihun Son),김사량(Sa Ryang Kim) 한국전산유체공학회 2007 한국전산유체공학회 학술대회논문집 Vol.2007 No.-
A general purpose program NUFLEX for the analysis 3-D thermo/fluid flow and pre/post processor in complex geometry has been developed, which consists of a flow solver based on FVM and GUI based pre/post processor. The solver employs a general non-orthogonal grid system with structured grid and solves laminar and turbulent flows with standard/RNG k-ε turbulence model. In addition, NUFLEX is incorporated with various physical models, such as interfacial tracking, cavitation, MHD, melting/solidification and spray model. For the purpose of verification of the program and testing the applicability, many actual problems are solved and compared with the available data. Comparison of the results with that by STAR-CD or FLUENT program has been also made for the same flow configuration and grid structure to test the validity of NUFLEX.