압연용 ROLL의 열처리를 위한 ROLL내의 열전달 해석

윤영환,김욱중 산업기술연구소 1987 産技硏論文集 Vol.1 No.-

Accumulator맥동의 Polytropic과정에 관한 연구

윤영환 國立 昌原大學校 産業技術硏究所 1996 産技硏論文集 Vol.10 No.-

Accumulator is a device which smooths pressure and fluid flow in fluid circulation systems. In order to design or size the accumulator, it is necessary to determine the value of n in polytropic process, pvⁿ=C for the air chamber in the accumulator. In this study, the experimental equipment for the value n consists of a solenoid valve, pressure transducers, and a level sensor in the flow circuit, where the solenoid valve gives pulsations to the air chamber. Experimental data from instant pressures and volumes show that the value n approaches n = 1.4 when a pulsation is rapid since its process is similar to a adiabatic process, and the value n approaches n = 1.0 when a pulsation is relatively slow since the process can be said to be close to a constant temperature process. And the sizes of the accumulator computed with measured values n are compared to the size of the tested accumulator. The errors between them are from 6.1% to 26.6%, which become smaller as the pulsation is slow.

사출기 유압 시스템 분석용 해석 모델 개발

윤영환,노대경,장주섭,전윤선,어승룡 유공압건설기계학회 2013 유공압건설기계학회 학술대회논문집 Vol.2013 No.6

교통사고 중·상해 판단기준에 관한연구

윤영환 경찰대학교 2009 경찰학연구 Vol.9 No.3

It is prescribed in the Article 4 Clause 1 of "act on special cases concerning the settlement of traffic accidents" that a driver who commits a crime by inflicting serious bodily injury through occupational or gross negligence of the crimes relating to traffic accidents shall not be prosecuted in case that he has comprehensive insurance. The law was legislated to fast recovery of the damage given by traffic accidents and to improve convenience in civic life. However, the law has brought undesirable results. It removed criminal responsibility from a driver who caused a grave traffic accident. Consequently, the law hindered driver's awareness of safety, infringed on victims' right to make a statement during proceeding trial and the right of national equality. Recognizing this problem, the Constitutional Court announced the Article 4 Clause 1 of "act on special cases concerning the settlement of traffic accidents" is against the constitutional law. According to the decision of the Constitutional Court, it became possible to prosecute drivers who caused grave traffic accidents. And some changes are expected like decrease of traffic accidents by inspiring awareness of traffic safety, diversification of automobile insurance policy, an increase of the police's work load related to traffic accidents and the specialization of handling grave traffic accidents. If a driver and victim do not come to a mutual agreement, even if the driver has a comprehensive insurance, it is possible to prosecute the driver who caused grave traffic accident so it became important to judge criteria of serious injury in traffic accidents. Except article 258 of criminal law there is no set criteria of serious injury and even article 258 of criminal law does not explain precisely what serious injury is. Moreover, there are almost no judicial cases, related to serious injury caused by traffic accidents, a lack of criteria of serious injury could cause legal disputes. As the Article 4 Clause 1 of "act on special cases concerning the settlement of traffic accidents" is unconstitutional in cases of causing serious injury to victims of traffic accidents, the prosecution sets a guideline concerning serious injury but that guideline is not concrete enough to resolve traffic accidents fairly and accurately. The concept of serious injury should be more concrete and clear than the concept in article 258 of the criminal law, and objective standards and guidelines are needed for this concept. Severity of Disability in the State Tort Liability Act or The Abbreviated Injury Scale (AIS), Injury Severity Score (ISS), which the medical profession uses as a standard of Trauma, can be used as guidelines concerning serious injury. If these guidelines are applied to the Act on Special Cases Concerning the Settlement of Traffic Accidents, it is possible to handle traffic accidents causing serious injury more objectively and clearly. A system in which health and academic experts participate should be set to judge serious injury correctly when the police and the prosecution are resolving traffic accidents.

엘리베이터용 로프 브레이크 시스템의 설계변수 최적화에 관한 연구

윤영환,최명진,장승호 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.6

Hydraulic systems of rope brake for elevators are modelled to evaluate design parameters such as cylinder pressure, piston displacement, accumulator capacity, and so on. To assure the results, experiments were performed. The analysis results agree well with the experimental results. The scheme in this study is expected to be utilized in the design of rope brake system for elevators to get design parameters and to improve the safety.

사각덕트내 직각엘보우를 지난 유체유동에 관한 연구

윤영환,배택희,박원구 한국마린엔지니어링학회 2002 한국마린엔지니어링학회지 Vol.26 No.6

Fluid flow in a rectangular duct with $90^{\circ}$ mitered elbow is measured by 5W laser doppler velocity meter. The fluid flow is also computed by commercial software of STAR-CD for comparison between measured and computed velocity profiles in the duct. Reynolds numbers for the comparison are 1,608 and 11,751 based on mean velocity and hydraulic diameter of the duct. First, the fluid flow of Reynolds number equal to 1,608 is predicted by assumptions of both laminar and turbulent models. But, even though the Reynolds number is less than 2,300~3,000, the computation by turbulent model is closed to the experimental data than that by laminar model. Second, the computation for Reynolds number of 11,751 by turbulent model also predicted the experimental data satisfactorily.

국내 옵셋 정면충돌 안전성평가방안

윤영환 한국자동차공학회 2008 한국자동차공학회 Symposium Vol.2008 No.10

두 개의 분지관을 가진 직사각형 덕트 내의 유량배분에 관한 실험 및 수치계산 연구

윤영환,배택희,박원구 대한설비공학회 2002 설비공학 논문집 Vol.14 No.9

Flow distributions in a rectangular duct with two branch ducts are measured by 5 W laser doppler velocity meter. The fluid flows are also computed by commercial soft-ware of STAR-CD for comparison between them. The Reynolds numbers in the main duct are from 4,226 to 17,491. The ratios distributed into two branches from the main duct are in-variant to Reynolds numbers according to both of numerical and experimental results. However computed velocity profiles at exit of each branch are somewhat different from measured profiles at the same location.

직각 엘보우를 가진 사각닥트내의 유체흐름에 관한 삼차원 수치 계산

윤영환,배택희,박원구 국립7개대학공동논문집간행위원회 2001 공업기술연구 Vol.1 No.-

Three dimensional fluid flow is computed in a rectangular duct with 90˚ wintered elbow by Finite Volume numerical method. The Reynolds number of the fluid flow is 12,186 based on mean velocity and hydraulic diameter of the duct, and the standard K-ε turbulent model is adopted for prediction of turbulent viscosity. The numerical results are compared with experimental data measured by laser doppler velocity meter. The distributions of fluid flow at middle and exit sections past the 90˚ elbow are compared with the experiment data at the same cross sections by taking the measured data at inlet as the inlet boundary conditions of numerical computation. The computed velocity components made relatively good simulation to the experimental data. But, in particular locations, the quantitative agreement between them is less satisfactory. Furthermore, it is also shown that turbulent kinetic energy has similar tendency with turbulent fluctuation components measured by experimental test.

음식물 소멸기용 냉각제습 열교환기의 개발

윤영환 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

In order to ferment the food wastes, air with proper temperature and humidity may be supplied. The air passed the moist wastes becomes highly humid air. Then the air should be dehumidified to recirculate into the system. In this paper, a simple double-pipe heat exchanger, in which moist air and refrigerant flow into inner and outer pipes respectively, is tested to dehumidify the moist air. From the experiments, it is found that dehumidification efficiency is 88.9% to 77.9% and overall heat transfer coefficient between moist air and refrigerant is 321.6 to 1091.9W/m2℃ as mass flow rate of air is increased.