리버스 무단 댐퍼용 연속가변밸브의 튜닝 파라미터에 관한 연구

윤영환(Young-Hwan Yoon),최명진(Myung-Jin Choi),유송민(Song-Min Yoo) 한국자동차공학회 2002 한국 자동차공학회논문집 Vol.10 No.3

Semi-aetive suspension systems are greatly expected to be in the mainstream of future controlled suspensions for passenger cars, In this study, a continuous variable damper for a passenger car suspension is developed, which is controlled actively and exhibits high performance with light weight, low cost, and low energy consump­tion. To get fast response of the damper, reverse damping mechanism is adapted, and to get small pressure change rate after blow-off, a pilot controlled proportional valve is designed and analyzed. The reverse continuous variable damper is designed as a HS-SH damper that offers good body control with reduced transferred input force from tire, compared with any other type of suspension system. The damper structure is designed, so that re­bound and compression damping force can be tuned independently, of which variable valve is placed externally. The rate of pressure change with respect to the flow rate after blow-ofT becomes smooth when the fixed orifiee size increases, which means that the blow-off slope is controllable using the fixed orifice size. The damping force variance is wide and continuous, and is controlled by the spool opening, of which scheme is usually adapted in proportional valves. The reverse continuous variable damper developed in this study is expected to he utilized in the semi-active suspension systems in passenger cars after its performance and simplicity of the design is con­firmed through real car test.

X-by-Wire System의 개발현황

윤영환(Young-Hwan Yoon),장주섭(Joo-Sup Jang) 한국자동차공학회 2004 오토저널 Vol.26 No.1

이중진공관형 태양열 집열기의 성능시험에 관한 연구

윤영환(Yoon Young-Hwan),김경환(Kim Kyung-Hwan) 한국태양에너지학회 2005 한국태양에너지학회 논문집 Vol.25 No.2

건식 변압기의 단락강도 예측

윤영환(Young-Hwan Yoon),안현모(Hyun-Mo Ahn),오연호(Yeon-Ho Oh),한성진(Sung-Chin Hahn) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.4

본 논문에서는 계통간 단락사고 시 권선에서 발생되는 전자력을 해석하기 위해 50㎸A급 시험용 변압기를 선정하였다. 외부회로를 이용해 단락 시험설비를 모의하여 단락전류를 계산하였으며, 단락사고 시 발생하는 누설자속을 계산하기 위해 유한요소법을 이용한 전자계해석을 이용해 해석하였다. 누설되는 자속밀도와 단락전류를 이용해 각각의 권선에서 발생하는 전자력의 크기와 분포를 계산하였다.

가속도한계 및 저크한계를 고려한 열차자동운전장치의 위치기반 속도프로파일의 계산 및 적용

윤영환(Young-hwan Yoon),엄정규(Jung-kyou Um),한재문(Jae-mun Han),조용기(Yong-gee Cho) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.7

This paper describes the calculation and application of the speed profile for the train speed control when the train is operated by ATO(Automatic Train Operation). We propose a speed profile calculation method considering the speed limitation and the jerk limitation, in order to maintain the quality of the train automatic operation. In previous works, ATO calculates a desired speed profile along the time, and controls the train to follow the profile. In this case, it may be hard to follow the restrictive speed along the location or to stop the train with a low location error, because of the difference between the desired location at each time and the real location of the train due to the control error. In the proposed method in this paper, we calculate a desired speed profile along the time considering the speed and jerk limitation first, and derive a speed profile along the location using it. If the restrictive speed profile is changed or the train speed strayed from the speed profile, ATO system calculates new speed profile and applies it immediately. Because ATO system controls the train speed based on the train location, the accuracy of the train location control can be improved. A simulation system for the test of the automatic train operation using this method is designed

유한요소법을 이용한 50kVA급 건식변압기의 단락특성 해석

윤영환(Young-Hwan Yoon),안현모(Hyun-Mo Ahn),오연호(Yeon-Ho Oh),한성진(Sung-Chin Hahn) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7

본 논문에서는 계통간 단락사고시 발생하는 단락전류가 변압기에 미치는 특성을 유한요소법을 이용해 해석하였다. 단락사고시 발생하는 단락전류는 시험설비의 외부회로를 적용하였으며, 누설자속밀도는 자계해석으로 계산하였다. 그리고 단락전류와 누설자속밀도에 의해 변압기의 각 권선에서 발생하는 단락강도 특성을 축방향, 반경방향의 전자력으로 계산하였다.

나선형 파일을 이용한 말뚝기초에 관한 연구

윤영환(Young-Hwan Yoon),강시온(Si-On Kang),조영동(Young-Dong Cho),김상환(Sang-Hwan Kim) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.3

본 연구는 나선형 파일을 이용한 말뚝기초에 관한 연구이다. 구조물이 안전하게 유지되기 위해서는 지반과 지상구조물을 연결해주는 기초가 필요하다. 그러나 인접 구조물이나 도시 지역에 기초를 건설할 때, 소음 및 진동 등에 의해 문제가 발생한다. 이러한 단점을 보안하기 위해 저진동, 저소음의 새로운 형상인 스파이럴 기초에 대한 연구를 수행하였다. 스파이럴 기초에 관한 연구는 축소모형실험을 수행하였으며, Meyerhof의 지지력 이론식 결과와 비교하였다. 말뚝기초 모형의 나선형 말뚝은 각기 다른 피치각도 및 길이 별로 제작 되었으며, 하중재하실험을 통하여 지지력을 측정 하였다. 축소모형실험 결과 나선형 말뚝의 피치 각도 및 길이가 증가 할수록 지지력이 증가함을 알 수 있었다. 실험에서 측정된 결과를 검증하기 위해 이론적 결과를 도입하여 실제 나선형 말뚝과 축소 제작된 말뚝의 지지력을 비교 검토 하였다. 연구결과를 통해 스파이럴 기초의 극한 지지력을 증가시키기 위해서는 기초의 길이와 피치각도를 증가시키는 것이 타당하다고 판단된다. 본 연구를 수행함으로써 기존의 기초건설 문제를 보완하고, 기초건설에 대하여 우수한 효과와 안전성 확보에 기여하고자 한다. This study examined a pile foundation using a spiral pile. To maintain the structural safely, a foundation for connecting the ground and the ground structure is needed. On the other hand, noise and vibration, etc. cause problems when constructing a foundation on adjacent structures or urban areas. A study of the spiral foundation of a new shape with low vibration and noise was carried out to solve these problems. A study of pile foundations was carried out on a scaled model test and compared with the results of Meyerhof"s bearing capacity theory. The scaled model test results showed that the bearing capacity increases with increasing pitch angle and length of the spiral pile. To verify the measured bearing capacity in a test with theoretical results, the bearing capacity of the actual spiral pile and scaled model pile were examined and compared. The ultimate bearing capacity of the spiral pile can be increased by increasing the foundation length and pitch angle. This study complements existing foundation construction problems and contributes to a better effect and safety.

연료전지용 소형 금속 열교환기의 성능에 대한 실험 및 이론적 연구

윤영환(Yoon,Young-Hwan),팽진기(Paeng,Jin-Gi) 한국태양에너지학회 2011 한국태양에너지학회 논문집 Vol.31 No.4

This study assessed the performance of a compact heat exchanger with staggered tube banks for recuperation of high temperature exhaust thermal energy for SOFC fuel cell system. The compact heat exchanger in this study is two pass system which consists of 315×202.5×48.5㎣ and 132 tubes of 6.0㎜Φ for each heat exchanger. From experiments of the 2 pass heat exchanger system, air temperature was increased from 50~85℃ to 402~482℃ while gas temperature was decreased from 600℃ to 305~402℃ according to mass flow rates of 3.9~7.8 g/s. The experimental heat transfer rates of the heat exchanger were compared with CFD numerical solutions with the conventional ζ-NTU method. From the comparisons, the following conclusions were obtained. For the heat exchanger system, the relative errors of heat transfer rate by CFD solution were from 7.1 to 27%, and those by ζ-NTU method were from 0.6% to 21% compared with experimental data. From the comparisons, it can be said that both of CFD and ζ-NTU method almost simulated to experimental data except specific conditions. Pressure drops through air tubes and gas passages were calculated with both of the CFD computation and head loss equations. The differences between them were from 14 to 22%.

포장에서 교잡종 옥수수의 도복과 수분스트레스간의 관계

조영손 ( Young Son Cho ),이병진 ( Byeong Jin Lee ),손다니엘 ( Daniel Son ),윤영환 ( Young Hwan Yoon ),양원하 ( Won Ha Yang ),서종호 ( Jong Ho Seo ),김충국 ( Chung Kook Kim ),손범영 ( Beom Young Son ) 한국국제농업개발학회 2011 韓國國際農業開發學會誌 Vol.23 No.4

Under field conditions, 22 corn hybrids(CHs) were tested for several characteristics related to lodging resistance and excessive water stress, such as pushing resistance on 1.0 and 1.5 m hights of the corns and breaking point. The 22 corn CHs were selected because they showed strongest pushing resistance and breaking resistance of culm as well as the highest thickness of basal culm, leaf greenness, leaf area, and plant height based on two pre-pot experiments performed in phytotron. To make excess water condition, water irrigation was done at 1) 20-d after seeding, 2) 5th leaf stage, 3) tasseling stage, and 4) silking stage with 100 mm/day for 5 days. Lodging-related characteristics were measured: culm diameter, root dry weight, weight balance of above-ground plant, breaking resistance, and breaking height in field experiment. Among all the characteristics tested, we explained in the two critical points for lodging resistance: 1) breaking resistance and breaking point, 2) culm diameter with breaking resistance and breaking point, and they were further evaluated for the relationships with the 1.0 and 1.5m height of above-ground plant. In the corn hybrids, there was a positive correlation between breaking resistant and weight balance of corn at the silking stage water treatment at 1.0 and 1.5-m height. And breaking resistant and culm diameter had a positive relationship at the 20-d water treatment at both measuring height. In conclusion, selection for lodging resistant hybrids or germplasms to excess soilwater should be made at the 5th leaf stage water treatment, and basal culm thickness should be considered to evaluate the resistance of the corn hybrid plants to lodging.

보리의 이삭목 말림성 遺傳과 이의 多面發現 效果

Chang Hwan Cho(曺章煥),Moon Woong Park(朴文雄),Young Hwan Yoon(尹榮煥),Jeong Il Ju(朱正一),Chung Ho Lee(李忠浩) 한국육종학회 1990 한국육종학회지 Vol.22 No.3

This experiment was conducted to determine the inheritance of twisted neck of spike node and to examine the associated characters with twisted neck in barley. The parents and F₂s of crossed lines between highly twisted neck variety Olbori and 5 nontwisted varieties and semi-twisted neck variety Saeolbori and 2 non-twisted varieties, were studied in field experiment at experiment farm, Dankook univ. Cheonan city, during 1988-1989 crop season. The results were as follows ; It was concluded that the twisted neck of barley was partially dominant and controled by additive effects of two ○○lymeric genes. There were varietal differences in twisted neck of barley mainly due to genetic background of parents. Broad sense heritability of twisted neck was relatively high and it was expected to high efficiency of selection. The characteristics of twisted neck of barley was negatively correlated with days to heading, length of lower internodes and 1,000 grain weight. Therfore the barley plants of twisted neck showed pleiotropic effects including early heading, lodging resistance due to shortening of lower internodes and light grain weight. There was no significant correlation between twisted neck and yield of barley, though twisted neck decrease 1,000 grain weight.