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상대식 승강장에서 열차 운행에 의한 지하철 승강장 스크린 도어 풍압해석
이명성(Myungsung Lee),이상혁(Sang Hyuk Lee),허남건(Nahmkeon Hur) 한국전산유체공학회 2007 한국전산유체공학회 학술대회논문집 Vol.2007 No.-
In the present study, the wind pressure transients on platform screen door in side platforms caused by passing trains have been investigated numerically. The transient compressible 3-D full Navier-Stokes solution is obtained with actual operational condition of subway train and the moving mesh technique is adopted considering the train movement. To achieve more accurate analysis, the entrance and exit tunnel of platform are included in a computational domain and detailed shape of train is also modeled. Numerical analyses were conducted on five operational conditions which are different velocity variation of subway train, existence of stationary train and passing each other trains. The results show that pressure load on platform screen door is maximized when the two trains are passing each other. It is also seen from the computational results that the maximum pressure variation was found to be satisfactory to various foreign standards.
이명성(Myungsung Lee),원찬식(Chan-Shik Won),허남건(Nahmkeon Hur) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.2
In the present study, a forest fire spread was simulated with a three-dimensional, fully-transient, physics-based, computer simulation program. Physics-based fire simulation is based on the governing equations of fluid dynamics, combustion and heat transfer. The focus of the present study is to perform parametric study to simulate fire spread through flat and inclined wildland with vegetative fuels like trees or grass. The fire simulation was performed in the range of the wind speeds and degrees of inclination. From the results, the effect of the various parameters of the forest fire on the fire spread behavior was analyzed for the future use of the simulation in the prediction of fire behavior in the complex terrain.
열차 운행에 따른 상대식 승강장에서 지하철 승강장 스크린 도어 풍압해석
이명성(Myungsung Lee),안혁진(Hyuk Jin Ahn),원찬식(Chan-Shik Won),허남건(Nahmkeon Hur) 한국전산유체공학회 2008 한국전산유체공학회 학술대회논문집 Vol.2008 No.-
The pressure-transient on platform screen doors in side platforms caused by passing trains with various operating conditions have been investigated numerically. The transient compressible three-dimensional flow simulations are performed with actual operating conditions of two trains by adopting moving mesh technique. To achieve more realistic results, the detailed shape of train and the subway station including tunnels connecting the adjacent stations are represented in the computational domain. Numerical analyses are carried out for cases considering arriving/passing/departing train with or without train stopped on the opposite track, and both trains on the move in opposite direction. From the numerical results, the maximum pressure on the platform screen doors, which is predicted in the case of two passing trains, satisfied the design standards for similar stations.
소음 상사를 이용한 직교류 홴의 유동 소음에 관한 수치해석 연구
이명성(Myungsung Lee),강성원(Seongwon Kang),허남건(Nahmkeon Hur),박정택(Jeongtaek Park) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
The flow noise of a cross-flow fan in an air conditioner indoor unit is investigated by a 2-D CFD simulation and acoustic analogy analysis. Transient flow field is obtained by solving the unsteady Reynolds-Averaged Navier-Stokes equation with the arbitrary sliding interface method to slide the grid for the relative motion of the rotating cross-flow fan. To predict the flow noise generated due to the cross-flow fan, an acoustic analogy analysis is performed with Ffowcs-Williams Hawkings model. The results show the details of transient flow field inside the air-conditioner including the typical eccentric vortex, which is appeared in the vicinity of the stabilizer. The strong interaction between the eccentric vortex and stabilizer is also well predicted, which is well known as the primary factor of the flow noise of the cross-flow fan. In order to validate the present analysis, the numerical result is compared with available experimental data such as the overall sound pressure level.
지형에 따른 발전기 배치가 풍력 발전 성능에 미치는 영향에 관한 수치해석 연구
이명성(Myungsung Lee),이승호(Seung Ho Lee),허남건(Nahmkeon Hur) 대한기계학회 2010 大韓機械學會論文集B Vol.34 No.10
복잡한 지형에 위치한 풍력발전소의 유동장을 분석하기 위해 3차원 유동해석이 수행되었다. 본 논문의 목적은 복잡한 지형과 풍력발전기의 배치가 풍력발전소의 성능에 미치는 영향을 연구하는 것이다. 자세한 블레이드 형상을 고려한 총 49대의 풍력발전기가 계산 도메인에 포함되었다. 풍력발전기의 회전운동을 고려하기 위해 고정회전자 기법이 사용되었고, 블레이드에 작용하는 토크를 계산함으로써 풍력발전기의 성능을 평가하였다. 수치해석 결과를 통하여 풍력발전소 전체의 자세한 유동장과 지형적 영향으로 풍속이 감소되는 국부적인 영역을 예측하였고, 상류의 발전기에서 발생하는 후류가 하류에 위치한 발전기의 성능에 미치는 영향도 분석되었다. 본 연구의 해석기법은 추후 건설되는 풍력발전소의 부지와 풍력발전기의 최적 위치를 선정하는 데 사용될 수 있을 것으로 사료된다. A three-dimensional flow simulation was performed to investigate the flow field in a wind farm on a complex terrain. The present study aims to examine the effects of mountainous terrain and turbine arrangement on the performance of wind power generation. A total of 49 wind turbines was modeled in the computational domain; detailed blade shape of the turbines was considered. Frozen rotor method was used to simulate the rotating operation. The torque acting on the turbine blades was calculated to evaluate the performance of the wind turbines. The numerical results showed details of the flow structure in the wind farm including the velocity deficit in the separated flow regions; this velocity deficit was due to the topographical effect. The effect of the wake induced by the upstream turbine on the performance of the downstream wind turbine could also be observed from the results. The methodology of the present study can be used for selecting future wind-farm sites and wind-turbine locations in a selected site to ensure maximum power generation.
다공성물질처리 기법을 이용한 대형판형열교환기의 성능평가에 대한 수치해석 연구
이명성(Myungsung Lee),정재혁(Jae Hyuk Jung),이나리(Nari Lee),허남건(Nahmkeon Hur) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-
In the present study, a numerical analysis is conducted in order to investigate the flow and the heat transfer characteristics of a large plate heat exchanger. To reduce computational load for prediction of overall performance, a semimicroscopic method has been adopted by using a porous media approach. The present numerical analysis successfully shows the details of the temperature and the pressure distributions in the large plate heat exchanger. Comparison of the pressure drop results of the present analysis with the available experimental data shows a good agreement.
이명성(Myungsung Lee),허남건(Nahmkeon Hur) 대한설비공학회 2011 대한설비공학회 학술발표대회논문집 Vol.2011 No.7
The Daegu metro station fire on February 18th, 2003 was a tragic accident which claimed 192 lives in South Korea. The fire was set by an arsonist in a stopped train at the Daegu metro station, and spread to other train arriving at the station in the opposite track. The present numerical study aims to reproduce the Daegu metro station fire using a transient 3-D CFD simulation with detailed geometry of the station and tunnels in order to understand the behaviour of the smoke and heat responsible for human losses in such accidents. The actual motion of the arriving train was also considered by using a moving mesh technique, and the fire development and CO gas generation were modelled with the enthalpy and scalar source terms. The evolutions of the temperature and CO gas distributions in the station were obtained in detail from the present simulation. The heat and CO concentrations at some critical locations such as staircases were shown and discussed in detail. The results of the present numerical study can provide useful data for future emergency plans of the metro stations in case of fire.