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유기수(Ki-Soo Yoo),유일수(Il-Soo Yoo),박무룡(Moo-Ryong Park),정명균(Myung-Kyun Chung) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
In recent application of volute pumps in industries, since the performance requirements vary widely depending on the application situation, the design point spans across the whole range of specific speed for the centrifugal type machine. Therefore it is necessary to make a volute pump design program capable of handling that various design points. In most recent optimum design codes for turbomachinery, the gradient method has been commonly used. However, since the range of design point is relatively wide, the non-linearity of the design variables often fails to produce the true optimum design. In this study a search method for the volute design is suggested in order to overcome the non-linearity of the variables. This method improves the convergence of the design program by confining the initial condition of the design variables using the random search method. Based on the search method, a user-friendly complete design program for volute pump has been developed.
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.
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.
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.
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.
카드뮴 (Cadmium)오염 조개 섭취가 생체장기에 미치는 연향의 실험적 연구
소진탁,유일수,박현,김숙향,김재진,민득영,Soh, Chin-Thack,Yoo, Il-Soo,Park, Hyun,Kim, Sook-Hyang,Kim, Jae-Jin,Min, Duk-Young 한국패류학회 1993 The Korean Journal of Malacology Vol.9 No.2
Contamination of heavy metals in water and sediments along Mantyeong (river) has reached up to critical level, The object of the study is to dlucidate some macroinvertebrates which inhabit along the river in respect to the modulatory role in reducing the pollution. For the purpose, Scapharca subcrenata(sea shell) which is common in numbers and biomass in the area was collected, and cadmium (Cd) was subjected as a reference metal in the experiment. The seashell was dried and autoclaved, followed by pellet preparation under various concentration of Cd: 50,100,250,500 and 1,500 ug /pellet. Mice were fed for 3 months, althrough last group(5 mice), 1,500 ug/pellet, died within 4 weeksof the administration.MT-Cd in liver and kidney increased in correlation with the amont of Cd concentration in pellet, especially in kidney than in liver. Liver and kidney of the mice showed pathological changes such as cellular infiltration and focal necrosis in liver, and peri-tubular cell infiltration or tubular necrosis etc. The changes were more intensive by amount of the Cd. Overall results in the present study suggest that Cd may eventually combine with soluble-protein forming metalloprotein, then reduce the toxicity of heavy metal, How the formed Mt-Cd is discharged from the kidney and the mechanism shall be the further subject to be clarified.
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.