• Title, Summary, Keyword: operating condition

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Effects of the Hydrostatic Test and the Operating Condition on Weld Residual Stress at a Safety Nozzle of the Pressurizer (수압시험 및 운전조건이 가압기 안전노즐의 용접잔류응력에 미치는 영향 평가)

  • Lee, Kyoung Soo;Lee, Sung Ho;Kim, Wan Jae
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.8 no.1
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    • pp.19-24
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    • 2012
  • This paper presents the results of finite element analysis for the effects of hydrostatic test and operating condition on the weld residual stress at dissimilar metal weld of a pressurizer safety nozzle in a nuclear power plant. For the study, the weld residual stress at ambient condition was analyzed using ABAQUS in the first place. After the weld residual stress analysis, the hydrostatic test condition and operating condition was applied to the same model one after another. The weld residual stress was observed to change due to the successive hydrostatic test and operating condition. The axial residual stresses on inner surface of the dissimilar metal weld and HAZ region were decreased by hydrostatic test and operating condition, which gives beneficial effect on preventing primary water stress corrosion cracking.

Study on The Qptimization of Operating Conditions of batch-type Grain Dryer (평면식 건조기의 적정작업조건 설정에 관한 연구)

  • 박경규;정창주
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.16 no.4
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    • pp.3600-3610
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    • 1974
  • Experimental work of batch-type dryer was conducted to develop its optimurm operating conditions by analyzing the major factors which affect the drying performance. A laboratory batch-type dryer was constructed and tested for various levels of heated-air rates, and depths of grain deposit. Tong-il rice variety having the initial moisture content of approximaely 23 per cent in wet basis was used for the experiment. The criteria selected for establishing the optimum operating condition were the drying performance rate, the thermal efficiency, and the operational cost of the dryer. The results of the study are summarized as follows: 1. The performance rate of dryer for a specific operating condition was defined as total amount of material dried per hour when the moisture content of grains in the upperlayer reaches to 16 per cent in wet basis. The optimum operating conditions as viewed in the rate of drying performance could be justified by functional realtionship between the depth of grain deposit and air flow rate. In other words, there was a definite depth of grain deposit for a given air-rate which make the dryer performance maximum. The optimum grain depth for the batch-type dryer with 3.3㎡ loading area and with the attached axial fan was about 35cm. 2. The thermal efficiency for the dryer was evaluated by the ratio of the latent heat required to evaporate the grain moisture to the heat input required to raise the ambient air-temperature to 40 degree centigrade. The optimum operating condition as viewed in term of thermal efficiency analyzed was that grater depth and lower air flow-rate may be desirable. This condition is contracted with the optimum condition as viewed by the dryer performance rate. 3. The annual operating cost of batch-type dryer was analyzed for different annual hour of use and for different operation condition. The optimum condition as viewed in terms of operating cost was almost identical to one as viewed in terms of dryer performance rate. Therefore, the most economical use of batch-type dryer for the same annual operating hours can be obtained when the dryer operated in the condition of maximum dryer performance rate. Increasing the annual operating hour may be desirable to cut down the dryer operation cost, since the annual hour of dryer use is much sensitive to the operating cost than any peractical conditions of dryer operation. 4. The most desirable operational condition as justified by combining all the criteria, dryer performance rate, thermal efficiency and annual operating cost, could be concluded to operate the dryer in the condition of maximum performance rate. The condition in general is identical to the lowest operation cost for a given annual operating hour.

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Reliability Evaluation of a Microgrid Considering Its Operating Condition

  • Xu, Xufeng;Mitra, Joydeep;Wang, Tingting;Mu, Longhua
    • Journal of Electrical Engineering and Technology
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    • v.11 no.1
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    • pp.47-54
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    • 2016
  • Microgrids offer several reliability benefits, such as the improvement of load-point reliability and the opportunity for reliability-differentiated services. The primary goal of this work is to investigate the impacts of operating condition on the reliability index for microgrid system. It relies on a component failure rate model which quantifies the relationship between component failure rate and state variables. Some parameters involved are characterized by subjective uncertainty. Thus, fuzzy numbers are introduced to represent such parameters, and an optimization model based on Fuzzy Chance Constrained Programming (FCCP) is established for reliability index calculation. In addition, we present a hybrid algorithm which combines scenario enumeration and fuzzy simulation as a solution tool. The simulations in a microgrid test system show that reliability indices without considering operating condition can often prove to be optimistic. We also investigate two groups of situations, which include the different penetration levels of microsource and different confidence levels. The results support the necessity of considering operating condition for achieving accurate reliability evaluation.

A study of the performance on large capacity screw compressors (중대형 스크루 압축기의 성능에 관한 연구)

  • Park, D.S.;Yang, S.H.;Lee, D.J.;Shin, J.K.;Yoo, S.Y.
    • Proceedings of the KSME Conference
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    • pp.668-671
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    • 2001
  • For the saving of energy consumption, it is necessary that the high efficient energy transfer machine. We found the optimum operating condition of screw water chiller during this performance test. The specifications of compressor for this performance test are as follows. Built-in volume ratio; Vi=2.4, using refrigerant; HCFC-22, nominal motor output; 60kW(80Hp). We found the test results on water cooled chiller standard test condition that the evaporating capacity is increased 8% maximum and 5.6% under same operating condition. and COP is increased 11 % max. and 8% under same operating condition with change of the evaporating inlet/outlet condition. For the results of these test, we can estimate the optimum operating condition of water cooled type screw chiller.

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A Study on Recognition of Operating Condition for Hydraulic Driving Members (유압구동 부재의 작동조건 식별에 관한 연구)

  • 조연상;류미라;김동호;박흥식
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.4
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    • pp.136-142
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    • 2003
  • The morphological analysis of wear debris can provide early a failure diagnosis in lubricated moving system. It can be effective to analyze operating conditions of oil-lubricated tribological system with shape characteristics of wear debris in a lubricant. But, in order to predict and recognize an operating condition of lubricated machine, it is needed to analyze and to identify shape characteristics of wear debris. Therefore, If the morphological characteristics of wear debris are recognized by computer image analysis using the neural network algorithm, it is possible to recognize operating condition of hydraulic driving members. In this study, wear debris in the lubricating oil are extracted by membrane filter (0.45 ${\mu}{\textrm}{m}$), and the quantitative values of shape parameters of wear debris are calculated by the digital image processing. This shape parameters are studied and identified by the artificial neural network algorithm. The result of study could be applied to prediction and to recognition of the operating condition of hydraulic driving members in lubricated machine systems.

Selection and Analysis of Operating Parameters for Condition Monitoring of Emergency Diesel Generator at Nuclear Power Plant (원자력발전소 비상디젤발전기 상태감시를 위한 운전인자 선정에 관한 연구)

  • Park, J.H.;Choi, K.H.;Lee, S.G.;Park, J.E.
    • Journal of Power System Engineering
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    • v.11 no.3
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    • pp.3-8
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    • 2007
  • The emergency AC power supply system of the nuclear power plant is designed to supply the power to the nuclear reactor at the emergency operating condition. The safety function of the diesel generator at the nuclear power plant is to supply AC electric power to the plant safety system whenever the preferred AC power supply is unavailable. The reliable operation of onsite emergency diesel generator should be ensured by a conditioning monitoring system designed to maintain and monitor and forecast the reliability level of diesel generator. To do this kind of diesel generator condition monitoring we reviewed several operating factors and history of the wolsong unit 3 diesel generator and selected the proper conditioning monitoring operating factors.

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Method to Estimate Expected Sag Frequency Considering the Operating Condition of Power System (전력계통 운전조건을 고려한 순간전압강하 추계 방법)

  • Son, Jeongdae;Lee, Kyebyung;Park, Chang-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.3
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    • pp.382-387
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    • 2016
  • This paper deals with the assessment of voltage sags regarding the variation of system operating conditions. In general, voltage sag assessment is performed by assuming the constant operating condition throughout the year. However, the assumption can lead to assessment errors in case of considerable changes of system operation condition. This paper presents a method to estimate ESF(expected sag frequency) considering the operating conditions according to the changes of power demand throughout the year.

Operating condition and air pollutant emission when do RPF co-combustion in coal fluid bed boiler (석탄유동층 보일러에 RPF 혼소시 운전조건 및 대기오염물질 배출 특성 변화)

  • Yoon, Kyoon-Duk;Park, In-Chul;park, Jong-Kyeong;Cho, Yeon-Haeng;Choi, Yeon-Seok;Shun, Do-Won;Park, Do-Hyun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.527-530
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    • 2006
  • Because price of fossil fuel rises, necessity about alternative energy was risen. Studied co-combustion of RPF to coal fluid bed boiler by necessity of these althernative energy. Purpose of this study to coal fluid bed bioler RPF when did co-combustion, change operating condition and characteristic of air pollutant examine according to change of fuel characteristic, operating condition examined about combustion chamber temperature, oxygen content etc. and air pollutant examined about material that is included to allowable exhaust standard and dioxin. Co-combustion condition was 5%. It was no peculiar under test result operating condition. Concentration of Co and HCl rose according as do RPF co-combustion and the other pollutants had hardly changed. Dioxin is low concentration level more than $0.1ng-TEQ/Sm^3$. There was no pollutant that exceed akllowable exhaust standard for boiler but $SO_x,\;NO_x$ were exceeded about allowable exhaust standard for incinerating facility.

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Effect of Inlet Humidity Condition at Cathode Side on Performance of a Polymer Exchange Membrane Fuel Cell (캐소드극 입구 가습 조건이 고분자 전해질 연료전지의 성능에 미치는 영향)

  • Moon, Cheor-Eon;Lee, Seo-Hee;Ko, Dong-Soo;Yang, Jang-Sik;Choi, Gyung-Min;Kim, Duck-Jool
    • Proceedings of the KSME Conference
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    • pp.3423-3428
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    • 2007
  • This paper shows that inlet humidity condition at cathode side is one of dominant parameters affecting the performance of PEMFC. To investigate effects of inlet humidity condition, the performance measurements were conducted for a single PEMFC with two operating variables : cathode relative humidity and dry condition in anode dry. The fuel cell employed for the experiments is a unit PEMFC with a 25$Cm^2$, Nafion$^(R)$112 membrane. As a result of this study, the cell performance is getting higher by increasing inlet humidity condition at cathode side. The cell performance is different from each operating temperature an it has maximum30% higher than dry condition at 60$^{\circ}C$ operating temperature with 80% relative humidity.

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Optimum Operating Condition of Air Heating Solar Collector Regenerator Using RSM Technique (RSM 기법을 애용한 태양열 집열판 재생기의 운전 조건 최적화)

  • Jung Jae-ho
    • Proceedings of the KAIS Fall Conference
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    • pp.89-91
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    • 2004
  • This study examines a regeneration process using hot air heated by solar radiation to recover absorption potential by evaporating moisture in liquid desiccant. More specifically, this study is aimed at finding the optimum operating condition of the regenerator by utilizing a well-established statistical tool, so-called design of experiment, and optimization techniques. It is demonstrated that an optimization model to find the optimum operating condition can be obtained using the functional relationship between regeneration rate and affecting factors which is approximated on the basis experimental results.

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