http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
밸브 디스크 차단비 변화가 버터플라이밸브의 손실계수에 미치는 영향에 관한 실험적 연구
노병준(Byungjoon Rho),이지근(Jeekeun Lee),최희주(Heejoo Choi) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.1
The loss coefficient of the butterfly valve which allows partial opening of the valve at closed position and is applicable to the small-sized pipe system with the diameter of 1 inch was measured for the variation of the valve disk blockage ratio. Two different types of the valve disk configuration to adjust the blockage ratio were considered. One was the solid type valve disk of which the diameter was changed into the smaller size rather than the pipe diameter, and the other was the perforate type valve disk on which some holes were perforated. The results from two types of valve disk were compared to identify their characteristics in the loss coefficient distributions. The loss coefficient and the controllable angle of the valve disk were decreased exponentially with the decrease of the blockage ratio. In addition, the perforate valve disk had the effect on the higher loss coefficient rather than the solid type valve disk.
밸브 닫힘각 변화에 따른 버터플라이밸브의 손실계수 평가
이지근(Jeekeun Lee),노병준(Byungjoon Rho),최희주(Heejoo Choi) 한국항공우주학회 2008 韓國航空宇宙學會誌 Vol.36 No.1
밸브 디스크 직경이 25.4 ㎜ 인 소형 버터플라이밸브의 유동특성이 다양한 밸브 닫힘각에 대해 실험적으로 연구되었다. 밸브 디스크각이 작은 경우 유량조절특성을 향상시키기 위해 주어지는 밸브 닫힘각을 0°, 5°, 10°, 20°, 30°로 변화시켜 밸브 디스크각에 따른 손실계수를 측정하였다. 또한 밸브선단 형상이 손실계수 변화에 미치는 영향을 조사하였다. 밸브 닫힘각이 증가함에 따라 최대손실계수는 감소하며, 밸브 닫힘각 0°~5°에서 가장 큰 감소를 나타냄을 알 수 있었다. 밸브 디스크 형상에 따른 손실계수는 밸브 닫힘각이 0°인 경우 날카로운 모서리를 갖는 디스크가 더 큰 손실계수를 나타낸 반면, 닫힘각 10°의 경우 날카로운 모서리를 갖는 디스크의 경우가 더 낮은 손실계수를 나타냄을 알 수 있었다. In this study, flow characteristics of a small-sized butterfly valve with the valve disk diameter of 25.4 ㎜ have been investigated experimentally for the valve closed angles. In order to examine the flow characteristics of the butterfly valve, loss coefficient (K<SUB>v</SUB>) was obtained at the valve closed angles of 0°, 5°, 10°, 20° and 30°. In addition, the effects of the valve disk edge shape were examined. As the result of the experiment, the maximum loss coefficient (K<SUB>vmax</SUB>) was decreased with the increase of the valve closed angle, and it had the maximum decrease ratio at the valve disk angles of 0°~5°. The valve disk edge shape have an effect on the loss coefficient of the valve around the small valve closed angle.
이중 공기공급 이유체 선회노즐의 유량비 변화에 따른 미립화 특성에 관한 실험적 연구
강신명(Shinmyoung Kang),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
The regulations to reduce the exhaust emissions from vehicles are becoming increasingly stringent and encompassing more types of vehicles. In the case of heavy duty diesel engines, the Urea-SCR system is currently considered to reduce the NOx emission as a proved technology, and it is widely studied to get the high performance and durability. In the Urea-SCR system, urea-water solution is injected into the exhaust pipe using the specially designed nozzle with high precision dosing unit. However, the injection nozzles occur some problems, including nozzle clogging, deposition of urea-water solution on the inner wall of exhaust pipe. In this study, the atomization characteristics of the dual air supplying twin-fluid swirl nozzle were investigated experimentally using PIV and PDA systems. The effect of assist air flowrate supplying from the dual air port was investigated. The mean velocity, turbulent intensity and SMD distributions of the sprays were measured along the centerline and radial direction. As the experimental results, the higher axial velocity is observed in the central part of the spray, and the SMD decreased with the increase of ALR.
환기용 축류팬의 가이드핀 블레이드 형상변화에 따른 유동특성에 관한 연구
박홍광(Hongkwang Park),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 대한설비공학회 2007 설비공학 논문집 Vol.19 No.12
The effects of a guide fin blade on the flow characteristics in a ventilating axial fan were investigated experimentally. The guide fins were setup onto the pressure surface of the blade, and their effects on the flowrate were evaluated. Two types of the guide fin blade were designed. One is the stem fin blade, and the other is the radial fin blade. The stem fin is designed normal to the circumference of a circle, and the radial fin is designed along the circumference of a circle. The results from the guide fin blade fans are compared with that of the blade without guide fins. The position and the geometry of the radial fin setting up on the blade have an effect on the increase of flowrate with the minor sacrifice of rotational speed of the blades. The radial fin positioning at 0.84 times blade diameter shows highest performance in the flowrate. The increase of the blade weight resulting from applying the guide fins shows minor effect on the variation of rotational speed of the blades.
차실내 Defrost 노즐 분류의 충돌각 변화에 따른 유동특성에 관한 실험적 연구
김덕진(Duckjin Kim),김현주(Hyunjoo Kim),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 대한기계학회 2007 大韓機械學會論文集B Vol.31 No.12
The flow characteristics with the impinging angles of defrost nozzle jet inside a commercial vehicle passenger compartment were investigated experimentally by using the two-dimensional duct-nozzle model. The shape of the nozzle contraction was designed according to the curved line of cubic equation to the vertical plan of the flow direction. The impinging angles, defined as the angle between nozzle axis and a vertical line to the windshield, were varied from the 0° to 80°. The mean velocity distributions, the half-widths, and the momentum distributions with the cases of both the free jet and the impinging jet onto the dummy windshield were measured. The impinging jet flows similarly with wall jet from X/bo=20, and the impinging angle has an effect on the half-width of the impinging jet. The momentum distributions onto the windshield increased with the increase of impinging angle, and then their inflection point was observed around the impinging angle of 60°.
이유체 노즐의 액체 이송 공기 공급 방법에 따른 유량변화에 관한 연구
조민호(Minho Cho),김덕진(Duckjin Kim),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
The urea-water solution in the urea-SCR system is generally injected into the exhaust gas by the two-fluid nozzle with the adaptor that allows the carrier air supply. In this paper, the effects of carrier air supplying parameters on the variation of liquid flowrate in two-fluid nozzle were investigated by using the five times magnified nozzle adaptor model. The carrier air supplying positions and liquid-air supplying conditions were considered as the experimental parameters. The internal pressure of the adaptor and the flow rate issuing from the injection nozzle were measured at the liquid supplying pressure from 2 to 4 bar and carrier air supplying pressure from 1 to 3 bar. As the results from the experiment, the internal pressure of the adaptor and the flowrate issuing from the injection nozzle were varied with the carrier air supplying position and the differential pressure between the liquid-carrier air pressures.
조민호(Minho Cho),강신명(Sinmyoung Kang),최윤준(Yoonjoon Choi),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 한국자동차공학회 2007 한국자동차공학회 지부 학술대회 논문집 Vol.- No.-
The urea-selective catalytic reduction(SCR) system to reduce NOx emission needs the precise flowrate control to prevent ammonia slip, and the urea-water solution in the system is generally injected into the exhaust gas by the two-fluid nozzle with the adaptor that allows the carrier air supply. In this paper, the effects of carrier air supplying parameters on the variation of liquid flowrate in two-fluid nozzle were investigated by using the five times magnified nozzle adaptor model. The carrier air supplying positions and liquid-air supplying conditions were considered as the experimental parameters. The internal pressure of the adaptor and the flowrate issuing from the injection nozzle were measured at the liquid supplying pressure from 2 to 4 bar and carrier air supplying pressure from 1 to 3 bar. As the results from the experiment, the internal pressure of the adaptor and the flowrate issuing from the injection nozzle were varied with the carrier air supplying position and the differential pressure between the liquid-carrier air pressures.