http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
저비속도 다단 원심 회전차 외경가공시 축추력 평형을 위한 평형피스톤 수정방안
유일수(Il Su Yoo),박무룡(Mu Ryong Park),윤의수(Eui Soo Yoon) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
In present study, the unbalance in axial thrust and the change of volumetric efficiency when trimming the impeller diameter have been investigated. Present study is for the low specific speed multistage centrifugal pumps with balance piston as balancing mechanism. The effect of impeller trimming on the axial thrust balance has been compared in multistage pumps with horizontal axis and vertical axis. As a result of impeller trimmings, an additional axial thrust acting to pump inlet direction. Axial thrust unbalance by impeller trim has presented severely in vertical axis pumps than horizontal axis pump. The balance piston's diameter is required to be increasing proportion to impeller trim rate for maintaining axial thurst balance. And increase in piston length in parallel with increase in piston diameter was more effective to reduce axial thrust unbalance and volumetric efficiency drop as well.
비압축성 재생형 기계에 대한 개선된 운동량 교환 이론 (Ⅰ)-수력학적 모델-
유일수(Il Su Yoo),박무룡(Mu Ryong Park),정명균(Myung Kyoon Chung) 대한기계학회 2004 大韓機械學會論文集B Vol.28 No.10
Momentum exchange theory has been generally used for an analysis of the regenerative turbomachines due to Its direct description of the complicate circulatory flow. However, because Its application is limited only to linear region and Its model equations are Incomplete on three variables, it needs further refinements. In the present study it is unproved by introducing a central pivot of circulatory flow. Also, by assuming linear circulatory velocity distribution, mean radii of inlet and outlet flows through the Impeller are newly suggested. By applying control volume analysis to both linear region and the acceleration region. the governing equation on the circulatory velocity is derived As a result, systematic performance analysis on the entire region of the incompressible regenerative turbomachines can be earned out based on the proposed model equations.
저비속도 원심 회전차 외경가공에 따른 축추력 불균형을 감쇄시키기 위한 평형 피스톤 수정방안에 관한 고찰
유일수(Il Su Yoo),박무룡(Moo Ryong Park),윤의수(Eui Soo Yoon) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.9
회전차 외경 가공에 따른 축추력 평형 및 체적 효율 변화에 대하여 고찰하였다. 평형장치로 평형 피스톤이 장착된 저비속도 다단 원심 펌프를 연구 대상으로 해석을 수행하였다. 수평축 다단 펌프와 2종의 수직축 다단 펌프에 대해 해석 수행을 한 결과, 회전차 외경 가공에 의해 펌프 전방으로 추가적인 축추력이 발생하였다. 이러한 축추력 불균형은 수평축 펌프보다 수직축 펌프에서 크게 발생하였다. 축추력 불균형을 방지하기 위해 평형피스톤의 외경을 증가시키는 방안을 제시하였고, 이를 위해 필요한 평형피스톤의 직경 변화율을 산출하였다. 피스톤의 직경 변화량은 회전차 외경 가공률에 비례하여 증가 하였다. 피스톤 직경 변화량이 클수록 틈새 면적 증가로 인해 체적효율이 감소하므로, 피스톤의 길이를 함께 증가시켜 체적 효율의 감소를 방지하는 것이 효과적이다. In the present study, the imbalance in the axial-thrust and variation in the volumetric efficiency that occurred during the trimming of impeller diameter were investigated. The present study was focused on low-specific-speed multistage centrifugal pumps with a balancing piston as the balancing mechanism. The effects of impeller trimming on the axial-thrust balance in multistage pumps with horizontal and vertical axes were compared. The results showed that impeller trimming resulted in an additional axial-thrust acting in direction of pump inlet. The axial-thrust imbalance due to impeller trimming was more severe in the vertical-axis pumps than in the horizontal-axis pumps. The rate of increase in the diameter of the balancing piston, which was proportional to the rate of impeller trimming, was evaluated to maintain the axial-thrust balance. Furthermore, a simultaneous increase in the piston length and piston diameter was more effective for reducing the axial-thrust imbalance along with the volumetric efficiency drop.
임펠러 앞전 깃 두께 변화에 따른 원자로 냉각재 펌프의 수력 성능 변화
유일수(Il Su Yoo),최원철(Won Chul Choi),박무룡(Mu Ryong Park),윤의수(Eui Soo Yoon) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
The reactor coolant pump consists of suction nozzle, impeller, diffuser, and discharge nozzle. Among them, impeller is required to be designed to satisfy performance requirements such as head, NPSH, and head curve slope at design point. In present study, the performance change with respect to leading edge thickness of impeller blade has been investigated in detail by computational fluid dynamics. As a results of comparison, the optimal design for leading edge thickness of impeller has been carried out to satisfy performance requirements.
수두 곡선 기울기를 고려한 원자로 냉각재 펌프의 수력설계
유일수(Il Su Yoo),박무룡(Mu Ryong Park),윤의수(Eui Soo Yoon) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
The RCP(reactor coolant pump), one of the key machines within nuclear plant, circulates the high-temperature and high-pressure reactor coolant. The hydraulic part in RCP consists of reactor coolant suction nozzle, casing, impeller, diffuser, and reactor coolant discharge nozzle. Among them, impeller, in particular, should be designed to satisfy performance requirements such as NPSHR and performance curve slope. Therefore a preliminary design method reflecting the performance curve slope at design flow rate is required to reduce time consuming due to design process of trial and error. Present study attempts to suggest the preliminary design method determining the approximate size of a pump to satisfy the design requirement like above. In this study, the flow field in mixed-flow pump designed by presently suggested preliminary design is simulated through the use of SST turbulent model.
유일수(Il Su Yoo),최원철(Won Chul Choi),황순찬(Soon Chan Hwang),박준영(Jun Young Park) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
CO2 pumps for transporting liquid CO2 from the capturing system into the marine or ground geological structure have been used. Classification of fluid or hydraulic pumps is based on fluid flow pattern through pumps and fluid supplied by pumps. In transporting CO2 system, positive displacement type pumps are usually placed for their working conditions at low specific speed regimes. In present study, however, a turbo type pump is intended to design for CO2 transporting continuously not intermittently. Pressurizing pump has been designed to a regenerative pump which is appropriate to produce high pressure in a single stage but it has low efficiency nevertheless. Present study investigated the hydraulic performances and flow phenomena numerically by using the commercial code. And then, experimental verification has been carried out.
윤의수,유일수,황순찬,오형우,Yoon, Eui-Soo,Yoo, Il-Su,Hwang, Soon-Chan,Oh, Hyoung-Woo 한국유체기계학회 2011 한국유체기계학회 논문집 Vol.20 No.1
A circulating pump with installation space constraints was developed satisfying performance requirements such as flowrate, head and NPSHAv. The development procedures are composed of conceptual design, configuration design, performance analysis by CFD and performance test which were established in KIMM. The developed pump is OH4 type centrifugal pump which has a mixed-flow type impeller, a double volute and a rigid coupling. As a result of tests, the pump proved to meet all the requirements including space constraints and performance.