Air flow field characteristics in a compact chamber system are indispensable for the efficient development of vehicle aerodynamic performance. In this study, air flow and velocity uniformity in the chamber system were numerically analyzed using the CFD method. Air flows at a uniform velocity from the outlet of the blower, passes fast through the heat exchanger with partial pressure difference, and then moves into the blower inlet. Overall pressure drop through the fan gradually increases with the flow rate. The uniformity varies along the test section, decreasing by 5-10% with distance from the nozzle. These predicted results can be widely used as basic conceptual design data for an efficient vehicle chamber system.

Various electronic control parts and devices installed in electric vehicles have greatly improved the convenience of occupants, but electromagnetic waves emitted from electronic devices have greatly increased concerns about malfunctions, deterioration of performance, safety accidents, etc. There are two models of analysis. Case A is symmetrical about one axis of rotation. Case B has two axes of rotation. In this study, a flow analysis was conducted to find excellent flow conditions in the mixing process to develop a paint with excellent electromagnetic shielding and thermal insulation performance. The results of the flow analysis are reflected in manufacturing specifications and are intended to be used to develop high-quality systems.

본 연구는 난방온실의 온도분포 균일화를 위한 기초자료 제공을 목적으로 온수난방 방식의 토마토 재배 온실 에서 난방실험을 통하여 난방배관의 표면온도와 실내기온 사이의 상관관계를 분석하고, 난방배관의 열전달특성 분석과 난방배관 배치의 개선을 통하여 난방배관 표면온도의 편차를 줄이고 균일도를 향상시키기 위한 방안을 도출하였다. 서로 다른 두 온실의 온도분포를 분석하여 최대편차와 균일도를 검토한 결과, 온수의 유량이 많고 난방배관의 길이가 짧게 배치된 온실의 온도편차가 작고, 균일도는 높은 것으로 나타났다. 또한 순환팬을 가동한 경우에 온도편차는 작아지고 균일도가 개선되는 것을 확 인할 수 있었다. 난방배관의 표면온도와 실내기온 사이의 상관관계를 분석한 결과, 두 온실 모두에서 유의적인 (p<0.01) 정적 상관관계가 있는 것으로 나타났다. 온수난방 온실에서 실내기온의 분포는 난방배관 표면온도의 분포에 영향을 받는다는 것을 확인할 수 있었고, 온도편차 가 최소화 되도록 난방배관을 배치함으로써 실내기온 분포의 균일도를 개선할 수 있는 것으로 판단되었다. 난방 배관의 열전달 특성을 분석한 결과 배관의 길이가 길어 지면 온도편차는 커지고, 관내의 유속이 빨라지면 온도 편차는 작아지는 것으로 나타났다. 따라서 지선배관의 길이가 짧아지도록 난방배관을 배치하고, 관내의 유속을 제어함으로써 온실의 온도분포와 환경의 균일성을 개선 할 수 있을 것으로 판단되었다. 국내 온실에서 가장 많 이 사용하고 있는 튜브레일(40A) 방식의 온수난방시스 템에서 하나의 지선배관에서의 온도편차를 3oC 이내로 조절하기 위해서는 관내의 유속이 0.2, 0.4, 0.6, 0.8, 1.0m·s-1일 때 난방배관의 길이는 각각 40, 80, 120, 160, 200m 이내로 제한해야 하는 것으로 분석되었다.

This study was successfully achieved out the optimized system for dispersing and mixing condition of resin liquid. The flow analysis was simulated according to the shape of the impeller and the stirring tank using ANSYS software and optimized in advanced design. As a result, it was confirmed that the shape and double number of the impeller on the flow field are influenced better effects in a range of mixing and diffusion areas comparing to single number of impeller. It was considered that stirring was performed more quickly and efficiently under the condition of double numbers and saw tooth type impeller. This result can be applied practically for the mixing tank in the industrial application and avaliable used to make a new system for painting equipment.

In this paper, we have studied about the Energy Storage System (ESS) for renewable energy such as wind and solar energy by using Battery Energy Storage System (BESS). The BESS, by using Li-Ion battery, takes the advantage of high energy density. The ESS is composed of a large number of the battery. It is necessary to stabilize the temperature of the battery in order to improve the performance of the ESS. To improve the performance of ESS, Using as a program to analysis the container internal flow and heat distribution. The use of the battery to the stable and suggest in the initial battery array design of the heat concentration phenomenon in the battery array

We have performed CFD simulation and analyzed flow and concentration fields for the basic data of the ventilation system for removing pollutants which were produced in a lecture room. The flow patterns indicated differently according to the arrangement of openings and the concentration distribution of pollutants were showed higher and lower because of the effect of that flow patterns. In the case of arranging the openings to the upper and lower side, the stagnation appearance of flow formed in the interested space. In the case of arranging the openings to the right and left side, the stagnation of high concentration pollutants appeared in the middle area of the interested space. On the increasing exhaust velocity, the distribution of pollutants appeared similar to the normal case, but the concentration of pollutants were lower.

가상의 심지층 처분 부지에서 이루어진 지하수 유동 모의 결과를 이용하여 처분 심도의 지하수 유량 분포를 분석하고 그 결 과를 처분 안전성 평가에 이용할 수 있는 방안을 제시하였다. 처분 심도의 지하수 유동량은 가상의 처분 부지를 대상으로 한 광역 및 국지적 지하수 유동 모의 결과의 지하수두 분포를 이용하여 분석하였다. 지하수 유동량 분포를 이용하여 처분공 위 치의 지하수 유동량을 분석하고 최대값을 기준으로 지하수 유동량을 표준화하여 처분공에서의 처분 용기 파손 가능성을 확 률적으로 도시하였다. 확률적으로 제시된 처분 용기의 파손 가능성을 이용하여, 처분 용기로부터 누출이 일어날 것으로 가 정된 위치에서 지표 환경으로 이동하는 방사성 핵종의 이동량에 대한 확률론적 기대값을 계산하여 결정론적으로 평가된 이 전 연구 결과와 비교하였다. 이런 평가 방법은 현장 조건을 더욱 많이 반영할 수 있는 안전성 평가 방안 구축에 기여할 수 있 을 것으로 생각된다.

Water discolouration and increased turbidity in the local water service distribution network occurred from hydraulic incidents such as drastic changes of flow and pressure at large consumer. Hydraulic incidents impose extra shear stresses on sediment layers in the network, leading to particle resuspension. Therefore, real time measuring instruments were installed for monitoring the variation of water flow, pressure, turbidity and particulates on a hydrant in front of the inlet point of large apartment complex. In this study, it is attempted to establish a more stable water supply plan and to reduce complaints from customers about water quality in a district metering area. To reduce red or black water, the water flow monitoring and control systems are desperately needed in the point of the larger consumers.

The water distribution system should be invariably operated on continuous pattern for 24 hours a day. Occasionally, it is not practically possible to operate for 24 hours due to water shortage or financial constraints. Therefore an intermittent water supply is unavoidable in water shortage area and developing countries.But the intermittent water supply can introduce large pressure forces and rapid fluid accelerations into a water supply network. These disturbances may result in new pipe failure, leakage and secondary contamination.This paper proposed an improvement methodology to prevent the disturbances by intermittent water supply. For the study, the hydraulic variation of intermittent flow in water distribution system was measured and analyzed in the field by comparing with simulation of hydraulic model. Installations of control valves such as, pressure reducing and sustaining and air valves were employed for pressure and flow control. The effectiveness of the methods are presented by comparing hydraulic conditions before and after introducing the proposed solutions.

The temperature distribution of a generic battery module was analyzed for different flow rates of cooling fluid. For the given battery module design, the temperature of battery cell near the inlet is higher than that of battery cell near the outlet. Because the inlet is located at the higher elevation than the top of battery electrodes, most of the incoming cooling fluid flows directly towards the battery housing wall above the outlet. For the inlet velocities of 1, 3, 5 m/s, the maximum temperature differences are 28, 19, 15 degrees Celcius respectively.

In general, a valve body of the automatic transmission(AT) is controlled by the clutch, the brake and lubricating oil flow in a hydraulic system and lubricant flow for each valve can be adjusted independently. To increase the lifetime of AT, the lubrication flow rate in a valve body for a 6 speed AT based parallel hybrid electric vehicle must be provided with proper oil distribution and control. In this study, we carried out several experiments without the inner parts of AT and with a AT assembly. The variation of the flow rate on oil temperature and pressure between an oil supply port and the outlets of the lubrication port was evaluated and analyzed. In the case of AT without the inner parts, it was evident that as the oil required for an operation of the clutch and brake was discharged from the outlet port, the flow rate from each lubrication port is decreased. However, the flow rate of the AT assembly was slightly increased. In addition, the lubrication flow rate was increased with increasing the oil temperature, and also it was reduced with increasing the oil pressure. Details of the resulting data are discussed.

홍수조절지는 하천 제내지 측에 제방을 축조하고 제방 일부 구간에 횡월류위어를 설치해 일정규모 이상의 홍수사상 발생 시 홍수량 일부를 월류시켜 저류하는 홍수저감시설이다. 다양한 하천시설물이 존재하는 하천 내에서 홍수조절지의 운영 최적화를 위해서는 기존 시설과의 연계 운영을 함께 검토해야 할 필요가 있다. 본 연구에서는 하도 내 수문 시설의 영향을 고려해 홍수조절지 횡월류위어의 위치 변화에 따른 수로 내 수위 저감 및 유량 분담 효과를 분석하였다. 수문 시설의 영향을 고려하기 위해 수로 내 2문의 방사형 수문을 설치하였으며, 수문으로부터 상류 방향으로 횡월류위어의 위치를 이동시키며 수로 내 수위 변화와 횡월류위어의 월류량을 측정하였다. 실험 결과 횡월류위어의 위치가 수문에 가까울수록 수위 저감 효과가 크게 나타났으며, 유량 분담 효과는 큰 변화가 없는 것으로 확인되었다. 2개소 이상의 횡월류위어 운영 시에는 충분한 저류공간이 확보되어 횡월류 위어의 위치에 따른 수위 저감 효과의 변화가 크지 않은 것으로 확인되었다. 또한, 수문 운영 시 1개소 횡월류위어의 위치 변화에 따른 수위 저감율 을 경험식으로 산정해 향후 홍수조절지 계획 시 활용 가능한 기초자료를 제공하고자 한다.

In this study, the Chiu-2D velocity-flow rate distribution based on theoretical background of the entropy probability method was applied to actual ADCP measurement data of Gangjung Stream in Jeju from July 2011 to June 2015 to predict the parameter that take part in velocity distribution of the stream. In addition, surface velocity measured by SIV (Surface Image Velocimeter) was applied to the predicted parameter to calculate discharge. Calculated discharge was compared with observed discharge of ADCP observed during the same time to analyze propriety and applicability of depth of water velocity average conversion factor. To check applicability of the predicted stream parameter, surface velocity and discharge were calculated using SIV and compared with velocity and flow based on ADCP. Discharge calculated by applying velocity factor of SIV to the Chiu-2D velocity-flow rate distribution and discharge based on depth of water velocity average conversion factor of 0.85 were 0.7171 m3/sec and 0.5758 m3/sec, respectively. Their error rates compared to average ADCP discharge of 0.6664 m3/sec were respectively 7.63% and 13.64%. Discharge based on the Chiu-2D velocity-flow distribution showed lower error rate compared to discharge based on depth of water velocity average conversion factor of 0.85.