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차창환(Chang-Hwan Cha),권혁빈(Hyeok-Bin Kwon),남성원(Seong-Won Nam) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
CFD analysis has been conducted to evaluate the aerodynamic performance of railway system. This study has been adopted to numerical simulation of the flow characteristics caused by the face-lift of mud-flap in inter-car gap for KTX train. In the case of the basic shape, the results showed that vortex induced by instability of shear layer was strong in intensity. whereas, In the case of the revised shape, it is observed that intensity of the vortex became weak. This could predict that resonance phenomena of noise will decrease and generate small noise than that of basic shape. Also, on the basis of these results, we can suggest schemes to reduce considerably aerodynamic noise induced by flow instability in the inter-car gap.
차창환(Chang-Hwan Cha),한창우(Chang-Woo Han),박종민(Jong-Min Park),김한호(Han-Ho Kim),빈재구(Jae-Gu Bin) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
CFD analysis has been conducted to evaluate the concept design of the cooling system of large propulsion motor. This study has been adopted to 3D numerical simulation of the cooling performance according to the cooling concept design for large propulsion motor. Also, it is important to predict the temperature rising inside motor. We compared with temperature rise of the stator coil for the four cases of the cooling path design. In the case of the double zigzag ring type, the results showed that the temperature rise of the stator coil was fully satisfied with the cooling performance for motor design criteria.
김철숙(Chul-Sook Kim),차창환(Chang-Hwan Cha),조상문(Sang-Moon Cho),이승호(Seung-Ho Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Vegetable oil is the clean insulation oil which has less problem when there is the oil leakage from the transformers due to accidents or explosion of them because the biodegradability of vegetable oil is over 90%. Also it has advantage as noninflammable oil due to over 300℃ flashing point. Even though vegetable oil has many advantages, it has limitations as low cooling performance due to three times higher viscosity than existing mineral oil and poor insulation characteristic caused by high moisture content and water affinity. In this paper, we estimated the cooling performance between the mineral and vegetable oil. In the case of vegetable oil, this could predict that the temperature rise of top oil will increase about 4℃ than that of mineral oil. Also, on the basis of these results we can suggest cooling design to substitute vegetable oil for mineral oil.
이현우(Lee Hyun-Woo),한창우(Han Chang-Woo),차창환(Cha Chang-Hwan) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
To effectively remove the heat of the permanent magnet synchronous motor(PMSM), in this paper, applied geometry of rotor and cooling device was valued high performance. The numerical analysis was performed the entire model of PMSM, and also, compared with temperature rise test. The skew spider shaft, that is better heat removal performance than others, is applied rotor geometry and design the high cooling performance device with 2-way zigzag cooling path. Finally, flow direction and temperature distribution was evaluated the entire model compared with numerical analysis and test results, values were within 15%.
남성원(Nam Seong Won),권혁빈(Kwon Hyeok Bin),차창환(Cha Chang Hwan) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-
Numerical analysis has been conducted to simulate pedestrian flow in the model of two-storied subway station. Because almost all the subway stations are two or three storied structure, simulations are conducted for the passengers those who get off the train and pass the wicket. Passenger flow analysis is very important factor to design the station and also to manage the operation of subway system. In the subway station, pedestrians move to the horizontal directions as well as vertical ones. Therefore, to consider the movement of pedestrians is necessary for the guarantee of safety and conveniency. As the up and down floors are connected with step, escalator and elevator, the entire movements in the multi-storied station should be simulated as like a 3-dimensional flow. Numerical schemes for the directional sweeping are developed to prevent the dependency on physical structure of station and to determine primary direction and secondary one. By using the developed program, we compared the simulation results of the effects of the location and size of exit and elapsed time.
철도시스템 전산유체해석 표준 프레임웍을 이용한 KTX 차량 주변 압력장에 대한 수치해석
권혁빈(Kwon Hyeok Bin),남성원(Nam Sung Won),차창환(Cha Chang-Hwan) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-
A standard framework of CFD analysis for railway system has been developed to evaluate the overall aerodynamic performance of railway system and has been adopted to numerical simulation of the pressure field around KTX train. The framework is composed of standard aerodynamic model and standard aerodynamic performance to customize the general CFD solution process reflecting the characteristics of railway system such as various operation mode and performance factors. The results show that the standard framework of CFD analysis for railway system can provide objectivity and consistency to the CFD analysis for railway system and the pressure field around KTX train has been successively solved.
EV용 내부 매입형 동기식 전동기에 대한 회전체 구조설계에 대한 연구
오승태(Seung Tae Oh),최소해(So Hae Cho),최진우(Jin Woo Cho),차창환(Chang Hwan Cha) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
This paper provides background and summary information for recent machine parametric studies and the analysis of rotating shaft design on IPM (Interior Permanent Magnet) in EV (Electric Vehicle). Also, This research deals with the natural frequency and mode shape of rotating shaft of Interior Permanent Magnet Motor with bearing stiffness by FEA (Finite Element Analysis) S/W. We present the natural frequency characteristic variation of rotating shaft according to change bearing stiffness and operation speed condition. Presented design method will apply to the IPM motor design to be simple, compact and effective design for IPM motor in EV.
남성원(Nam Seong Won),권혁빈(Kwon Hyeok Bin),차창환(Cha Chang Hwan) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-
Insight into behaviour of pedestrians as well as tools to assess passenger flow conditions are important in for instance planning and geometric design of railway station under regular and safety-critical circumstances. Algorithm for passenger flow analysis based on DEM(Discrete Element Method) is newly developed. There are lots of similarity between particle-laden two phase flow and passenger flow. The velocity component of 1st phase corresponds to the unit vector of calculation cell, each particle to passenger, volume fraction to population density and the particle velocity to the walking velocity, etc. And, the walking velocity of passenger is also represented by the function of population density. Key algorithms are developed to determine the position of passenger, population density and numbering to each passenger. To verify the effectiveness of new algorithm, passenger flow analysis for the basic models of railway station is conducted.