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Urea-SCR 시스템의 히팅장치 설계를 위한 빙결된 Urea 수용액의 해동 특성에 관한 연구
황재순(Jaesoon Hwang),허형석(Hyeongseok Heo),이천환(Chunhwan Lee) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Among the after-treatment systems, urea-SCR system is one of the most efficient techniques to reduce nitrogen oxides emitted from diesel engines. However, urea-water solution is frozen at low ambient temperature level of below -11℃. The purpose of this study is to understand melting phenomena and to compare the melting characteristics between the two geometries - one is coil type and the other is zigzag type - of heater using engine coolant. Performance of the two kinds of heaters is analyzed by numerical study. It was found that melting time of zigzag type heater is shorter than coil type heater.
구조 강도 특성을 고려한 플라스틱 오일쿨러의 열전달 성능 설계
황재순(Jaesoon Hwang),허형석(Hyungseok Heo),이동은(Dongeun Lee),이헌균(Heonkyun Lee),김현철(Hyunchul Kim),이승주(Seungjoo Lee) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Until recently, work on compact metallic heat exchangers has sparked interest amongst heat exchanger manufacturers due to its enhanced thermal performance and energy saving benefits in comparison to conventional heat exchangers. Nevertheless, the operating limitations of these metallic heat exchangers have created the need to develop alternative units. It has been argued that the use of plastics can cause problems during design and manufacture owing to their low strength, relatively poor thermal conductivity and large thermal expansion. However, the advantages of plastics e.g., corrosion resistance, low cost, curtailment of weight, design flexibility etc., can compensate abundantly for the disadvantages. The purpose of this study is to develop high efficiency plastic oil cooler which can alternative metallic oil cooler. The performance analysis of various plastic tubes with oval type is accomplished by use of computational programs Fluent 6.3 and Ansys 10.0.
GDI 엔진용 고압 연료 펌프 설계를 위한 밸브의 유동 특성 해석
황재순(Jaesoon Hwang),허형석(Hyungseok Heo),이동혁(Donghyuk Lee),신외경(Waegyeong Shin),황재근(Jaekeun Hwang) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
High pressure fuel at about 20 MPa is injected into the engine cylinder. At a GDI system, it is a technology to reduce emission and to improve engine output and fuel efficiency at the same time. But, this system requires an additional high pressure fuel pump with a low-pressure fuel pump that is used to a PFI(Port Fuel Injection) engine. The purpose of this paper is to investigate the performance characteristics of the main valves of a high pressure fuel pump for GDI engine. The flow characteristics of inlet/outlet check valves and a relief valve of high pressure fuel pump were analyzed by CFD method. The flow rate of the inlet/outlet check valves are decided by the valve openings. Therefore the flow characteristics of the inlet/outlet check valves were analyzed according to the valve openings and inlet/outlet pressures. In case that high pressure abnormally occurs at the injector part, the relief valve begins to work. The bypass flow rate of the relief valve according to inlet and outlet conditions of the valves was analyzed.
알루미늄 다이캐스팅 EGR Cooler의 열유동 특성 평가
황재순(Jaesoon Hwang),허형석(Hyungseok Heo),이헌균(Heonkyun Lee),배석정(Sukjung Bae),이춘범(Chunbeom Lee),임창식(Changsik Lim),장용수(Yongsoo Jang) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Cooled EGR is an effective method for the reduction of NOx from a diesel engine. EGR cooler is the key component of the EGR system. Recently, high efficiency, high performance and compactness are required for the EGR cooler to meet the Euro-5 emission regulation. Besides, the cutdown of the price of EGR cooler is highlighted. Until now, most of EGR cooler are shell and tube type heat exchangers made of stainless steel. This study investigates the heat transfer performance characteristics according to the design modification of low-cost ALDC(aluminum die-casting) EGR cooler in the same volume basis, whose basic model consists of laminated tubes with rectangular cross section and flow pattern is U-flow.
황재순(Jaesoon Hwang),허형석(Hyungseok Heo),배석정(Sukjung Bae),이동혁(Donghyuk Lee),최해성(Haeseong Choi),김영삼(Youngsam Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Recently, works on compact heat exchangers have sparked interest amongst heat exchanger manufacturers to develop the compact heat exchangers with enhanced thermal performance in comparison to conventional ones. The purpose of this study is to design more efficient fin than commonly used louvered fin on the basis of same core size. Cooling capacity of louvered fin of conventional radiator is numerically analyzed and the performance is compared with that of the designed fin. Simulations were performed for different louver pitches with 0.9, 1.4 ㎜. In conclusion, cooling capacity of designed fin with 0.9 ㎜ louver pitch is increased more than 7% compared with the conventional fin even though the air side pressure drop increased.
황재순(Jaesoon Hwang),성경환(Kyounghwan Sung),김호윤(Hoyoon Kim) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
The number of livestock burial sites in Korea due to the occurrence of foot-and-mouth disease and avian influenza is approximately 6,000 in 2017. Although excavation is permitted at more than 4,800 livestock burial sites when their management periods have expired, carcasses of dead livestock in many other sites have rotten for a long time and remain underground. Several techniques have been developed to process carcasses of dead livestock, but some technical problems have not been solved, so technical development is now urgently required to rapidly and safely process dead-livestock carcasses. The present study proposes a solution for livestock burial sites, which uses a thermal hydrolysis process to safely and efficiently process undecomposed remaining carcasses in the sites. During the thermal hydrolysed process, there is a step for mixing a high viscous liquid. In this study, CFD analysis was performed to improve a mixing performance by a changing the shape of the mixer. And the performance of the mixer is quantitatively compared.
가변 제어를 위한 병렬 배치식 오일펌프의 엔진 모터링 성능 평가
황재순(Jaesoon Hwang),허형석(Hyungseok Heo),이헌균(Heonkyun Lee),이동혁(Donghyeok Lee),배석정(Sukjung Bae),정영대(Youngdae Choung),이병석(Byeongseok Lee) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Conventional mechanical engine oil pump is driven by engine power via belt mechanism, whose discharge oil flow increases linearly with engine rotating speed. This causes engine power loss because the mechanical oil pump supplies more excessive oil flow than required on the various engine speeds and temperature conditions. Automotive manufacturing companies are developing electric oil pumps to control the oil flow rate variably in the engine operation regions. However, on the low temperature conditions engine oil gets more viscous and requires more driving torque, so, the motor to drive the electric oil pump is required to have larger capacity and size. The solution to make up these defect is technique of parallel engine oil pumps consists of an electric pump and a downsized mechanical pump. This study aimed to analysis hydraulic performance of parallel engine oil pumps on the various operating conditions by engine motoring test.