고정밀도 솔레노이드 방식의 원자로 제어봉 위치지시기

백민호(Min-Ho Baek),홍훈빈(Hoon-Bin Hong),박희준(Hee-June Park) 대한전기학회 2016 전기학회논문지 Vol.65 No.11

Control Rod Position Indicator in nuclear reactor vessel has developed for small reactor in Korea. Because of severe environment in reactor vessel, target of this study is to develop the suitable position indicator. In this study, solenoid type position indicator made of Mineral Insulated Cable(MI Cable) was introduced to adapt in severe environment. And inductance of the solenoid was used to indicate the rod position for high precision. But problem of this concept is that a linear slope of inductance is changed by temperature effect. To resolve this problem, two sensing coils were introduced for temperature compensation. A role of the sensing coil is to make reference linear equation about certain temperature. To confirm this concept, also, inductance of solenoid and sensing coils were measured at room and high temperature (~300℃). The results of measurement show that the position error of sensing coil between room and high temperature was about 2%. But it was identified that this error was resulted from insufficient test environment (temperature error between solenoid and sensing coils was about 2% at high temperature condition). Therefore, solenoid type position indicator shows that it is very suitable in reactor vessel as a high precision rod position indicator.

선박용 저속 디젤엔진의 출력산정에 관한 연구

정균식(Kyun-Sik Jung),이진욱(Jin-Uk Lee),정진아(Jin-Ah Jung),최재성(Jae-Sung Choi) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4

Recently, EMS(Engine Monitoring System) is reported that the IHP calculated and measured from electronic indicator has a deviation compared to mechanical indicator. The same results has been shown in case of trainingship HANNARA, so it is required to analysis about the estimation of engine output. In this paper it is studied on the cause of error for engine performance analysis and investigated the reliability of engine output by the acquisition methods of cylinder pressure data.

선박용 디젤엔진의 출력산정에 관한 연구

정균식(Kyun-Sik Jung),이진욱(Jin-Uk Lee),정진아(Jin-Ah Jung),최재성(Jae-Sung Choi) 한국마린엔지니어링학회 2011 한국마린엔지니어링학회지 Vol.35 No.4

To obtain the engine output correctly is basically very important factor for estimating a engine performance. But, it has been reported that the IHP measured from electronic indicator such as MIPS(Mean Indication Pressure System) has a deviation compared to mechanical indicator. It was reported by authors that the uncertainty of crank angle for TDC position could be one of the reasons. In this paper, the uncertainty of crank angle for TDC position and its influence to engine output were investigated respectively about M/E and G/E for marine diesel engines. For the purpose, two sampling methods of pressure in cylinder were considered which were ‘angle base sampling’ and ‘time base sampling’. Angle base sampling is real crank angle acquired from angle encoder which is attached to crank shaft and time base sampling is crank angle calculated by detected revolution with Z-pluse of encoder. Time base sampling is same method of MIPS. This paper concluded that time base sampling method is not suitable for obtaining the output of marine diesel engine on board because of instantaneous speed variation and load fluctuation. Also it is verified that the variation of engine speed by load fluctuation should be one of reasons additionally in case of M/E.

A Study on the Performance Analysis of Francis Hydraulic Turbine

Jin-ho Ha,Chul-Ho Kim 한국마린엔지니어링학회 2009 한국마린엔지니어링학회지 Vol.33 No.7

The effects of varying the inlet flow angle on the output power of a Francis hydraulic turbine were studied numerically and the result was compared to the experimental results conducted at Korea Institute of Energy Research to determine the brake power of the turbine for each set of operating conditions. The loss of mechanical power of the model turbine was determined by comparing the numerical and experimental results, and thus the turbine efficiency or energy conversion efficiency of the model turbine could be estimated. From the result, it was found that the maximum brake efficiency of the turbine is approximately 46% at an induced angle of 35 degrees. The maximum indicated mechanical efficiency of the turbine is approximately 93% at an induced angle of 25~30 degrees.

Accuracy of structural computation on simplified shape

Marin, P. Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.2

This paper focuses on a number of criteria that enable controlling the influence of geometric simplification on the quality of finite element (FE) computations. To perform the mechanical simulation of a component, the corresponding geometric model typically needs to be simplified in accordance with hypotheses adopted regarding the component's mechanical behaviour. The method presented herein serves to compute an a posteriori indicator for the purpose of estimating the significance of each feature removal. This method can be used as part of an adaptive process of geometric simplification. If a shape detail removed during the shape simplification process proves to be influential on mechanical behaviour, the particular detail can then be reinserted into the simplified model, thus making it possible to readapt the initial simulation model. The fields of application for such a method are: static problems involving linear elastic behaviour, and linear thermal problems with stationary conduction.

Research on the Monitoring and Warning Mechanism about Operation of Funds in Universities of China

Zhai Huayun,Zheng Jun 한국경영교육학회 2011 한국경영교육학회 학술발표대회논문집 Vol.2011 No.12

Based on domestic and international early warning indicator system of funds security of universities, it is established the evaluation indicator system of funds security of universities in China from the micro level and the meso level of social, political and economic environments, and it is established the monitoring and warning mechanism about operation of funds in universities of China. Finally, it is analyzed the status of operation of funds in universities of China.

Accuracy of structural computation on simplified shape

P. Marin 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.2

This paper focuses on a number of criteria that enable controlling the influence of geometric simplification on the quality of finite element (FE) computations. To perform the mechanical simulation of a component, the corresponding geometric model typically needs to be simplified in accordance with hypotheses adopted regarding the component’s mechanical behaviour. The method presented herein serves to compute an a posteriori indicator for the purpose of estimating the significance of each feature removal. This method can be used as part of an adaptive process of geometric simplification. If a shape detail removed during the shape simplification process proves to be influential on mechanical behaviour, the particular detail can then be reinserted into the simplified model, thus making it possible to readapt the initial simulation model. The fields of application for such a method are: static problems involving linear elastic behaviour, and linear thermal problems with stationary conduction.

Influence of latitude wind pressure distribution on the responses of hyperbolodial cooling tower shell

Jun-Feng Zhang,Yao-Jun Ge,Lin Zhao 한국풍공학회 2013 Wind and Structures, An International Journal (WAS Vol.16 No.6

Interference effects are of considerable concern for group hyperboloidal cooling towers, but evaluation methods and results are different from each other because of the insufficient understanding on the structure behavior. Therefore, the mechanical performance of hyperboloidal cooling tower shell under wind loads was illustrated according to some basic properties drawn from horizontal rings and cantilever beams. The hyperboloidal cooling tower shell can be regarded as the coupling of horizontal rings and meridian cantilever beams, and this perception is beneficial for understanding the mechanical performance under wind loads. Afterwards, the mean external latitude wind pressure distribution, CP(θ), was artificially adjusted to pursue the relationship between different CP(θ) and wind-induced responses. It was found that the maximum responses in hyperboloidal cooling tower shell are primarily dominated by the non-uniformity of CP(θ) but not the local pressure amplitude CP or overall resistance/drag coefficient CD. In all the internal forces, the maximum amplitude of meridian axial tension shows remarkable sensitivity to the variation of CP(θ) and it’s also the controlling force in structure design, so it was selected as an indicator to evaluate the influence of CP(θ) on responses. Based on its sensitivity to different adjustment parameters of CP(θ), an comprehensive response influence factor, RIF, was deduced to assess the meridian axial tension for arbitrary CP(θ).

Influence of latitude wind pressure distribution on the responses of hyperbolodial cooling tower shell

Zhang, Jun-Feng,Ge, Yao-Jun,Zhao, Lin Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.16 No.6

Interference effects are of considerable concern for group hyperboloidal cooling towers, but evaluation methods and results are different from each other because of the insufficient understanding on the structure behavior. Therefore, the mechanical performance of hyperboloidal cooling tower shell under wind loads was illustrated according to some basic properties drawn from horizontal rings and cantilever beams. The hyperboloidal cooling tower shell can be regarded as the coupling of horizontal rings and meridian cantilever beams, and this perception is beneficial for understanding the mechanical performance under wind loads. Afterwards, the mean external latitude wind pressure distribution, CP(${\theta}$), was artificially adjusted to pursue the relationship between different CP(${\theta}$) and wind-induced responses. It was found that the maximum responses in hyperboloidal cooling tower shell are primarily dominated by the non-uniformity of CP(${\theta}$) but not the local pressure amplitude CP or overall resistance/drag coefficient CD. In all the internal forces, the maximum amplitude of meridian axial tension shows remarkable sensitivity to the variation of CP(${\theta}$) and it's also the controlling force in structure design, so it was selected as an indicator to evaluate the influence of CP(${\theta}$) on responses. Based on its sensitivity to different adjustment parameters of CP(${\theta}$), an comprehensive response influence factor, RIF, was deduced to assess the meridian axial tension for arbitrary CP(${\theta}$).

Mg₂NiH<SUB>x</SUB>-5 wt% CaO 수소 저장 복합재료의 물질전과정평가

신효원(Hyo-Won Shin),황준현(June-Hyeon Hwang),김은아(Eun-A Kim),홍태환(Tae-Whan Hong) 한국청정기술학회 2021 청정기술 Vol.27 No.2