발전소 Deaerator floor의 복사효과 저감을 위한 열유동 해석

김태권(Tae-Kwon Kim),하지수(Ji-Soo Ha),최용석(Yong-Seok Choi) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.12

화력발전은 화석연료인 석탄을 연소시켜 얻은 열에너지로 물을 끓여 증기를 만들고 그 증기로 터빈을 운전시켜 터빈축에 연결된 발전기로 전기를 얻는 방식이다. 따라서 하절기에는 화력발전소 Deaerator의 표면온도는 70℃, Storage Tank의 표면온도는 67℃, 공기온도는 50℃를 상회한다. 이런 현상은 기기와 작업자에게 부적합한 영향을 끼친다. 특히, Deaerator와 Storage Tank에 인접해 있는 작업자는 복사열전달의 영향을 받아 더 높은 체감온도를 느끼게 된다. 따라서 본 논문에서는 전산해석을 통해 Deaerator 부근의 열유동 특성을 파악하고 단열재를 사용하였을 때와 복사차폐막을 사용하였을 때의 효과를 비교하여 최적의 냉각조건을 제시하였다. Case 1은 현재 발전소의 형상이고 Case 2는 Case 1에서 단열재를 추가로 사용한 형상이고 Case 3은 Case 1에서 복사차폐막을 사용한 형상이다. 유동은 벽면과 열원의 온도 차이에 의해 발생되었고 오른쪽 상단부에 고온의 공기가 포집된다. 온도 분포에서 작업자표면의 최대 온도를 비교해보면 단열재를 사용한 Case 2가 복사효과 저감에 가장 효율적인 것으로 나타났다. Steam power generation is used to produce electricity through a generator that is connected to a steam turbine. As a result, the surface temperature of the deaerator is 70℃during the summer season, the surface temperature of the storage tank is 67℃, and the air temperature is 50℃. This environment is inappropriate for workers and instruments. Workers adjacent to the deaerator and storage tank in particular feel higher temperatures because of the radiative heat transfer effect. Therefore, we optimized the cooling conditions by computational analysis. Case 1 is the current shape of the power plant, Case 2 has additional insulation, and Case 3 has a radiation shield. Flow is caused by a temperature difference between the heat sources in the wall, and hot air is trapped in the right upper end. Based on the temperature contours and the maximum temperature of the surfaces, Case 2 was found to be the most efficient for reducing radiative heat transfer effects.

Fault Detection and Diagnosis of the Deaerator Level Control System in Nuclear Power Plants

Kim Kyung Youn,Lee Yoon Joon Korean Nuclear Society 2004 Nuclear Engineering and Technology Vol.36 No.1

The deaerator of a power plant is one of feedwater heaters in the secondary system, and it is located above the feedwater pumps. The feedwater pumps take the water from the deaerator storage tank, and the net positive suction head(NSPH) should always be ensured. To secure the sufficient NPSH, the deaerator tank is equipped with the level control system of which level sensors are critical items. And it is necessary to ascertain the sensor state on-line. For this, a model-based fault detection and diagnosis(FDD) is introduced in this study. The dynamic control model is formulated from the relation of input-output flow rates and liquid-level of the deaerator storage tank. Then an adaptive state estimator is designed for the fault detection and diagnosis of sensors. The performance and effectiveness of the proposed FDD scheme are evaluated by applying the operation data of Yonggwang Units 3 & 4.

Experimental Heat and Mass Transfer Coefficients of a Two Stage Spray and Packed Bed Deaerator

( K. V. Suryanarayana ),( R. A. Bakar ),( Chang Sik Lee ),( D. M. Reddy Prasad ),( K. V. Sharma ) 한국액체미립화학회 2010 한국액체미립화학회 학술강연회 논문집 Vol.2010 No.-

Experiments are conducted to study the influence of mass flow rate on heat and mass transfer coefficients in a two stage deaerator consisting of a spray stage and packed bed combination. It has been observed that an increase in mass flow rate of water increases the heat transfer coefficients in both the stages of the deaerator, whereas the mass transfer coefficients increases in the first and decreases in the second stage. The heat transfer coefficient in the spray stage is 300 times greater than that obtained in the packed bed. The mass transfer coefficient decreased by 2 times in the second stage with increase in flow rate in the range of experiments conducted. It has been observed that oxygen can be reabsorbed by the outgoing feed water under certain conditions of flow.

원전 탈기기 시스템의 수위 측정 센서의 고장 검출 및 진단

김봉석,이인수,이윤준,김경연,Kim, Bong-Seok,Lee, In-Soo,Lee, Yoon-Joon,Kim, Kyung-Youn 한국전기전자학회 2003 전기전자학회논문지 Vol.7 No.1

원전 탈기기 저장탱크의 기하학적 구조 및 정상 상태에서의 입출력 흐름율을 고려하여 동적 제어 모델을 설정하고, 적응 추정기를 이용하여 수위 측정 센서의 고장 검출 및 진단 기법을 제안하였다. 영광 3, 4호기의 실제 운전 데이터를 적용하여 제안된 고장 검출 및 진단 기법의 성능을 평가하고 타당성을 검증하였다. In this paper, dynamic control model is formulated by considering the geometrical structure of the deaerator storage tank in nuclear power plant and input-output flow rate at steady state, and we describe fault detection and diagnosis (FDD) scheme based on the adaptive estimator. The performance and effectiveness of the proposed FDD scheme are evaluated by applying real operating data obtained from the YOUNGKWANG 3 & 4 FSAR.

VOF모델을 활용한 스플래시 현상에 대한 CFD연구

김상호(Sangho Kim),유미우루노(Yumi Uruno),정재원(Jaewon Chung) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

발전소 터빈건물의 창문 위치에 따른 온도저감

하지수(J. S. Ha),김태권(T. K. Kim),정경호(K. H. Jeong) 한국에너지학회 2016 에너지공학 Vol.25 No.4

화력발전소 터빈 본관의 환풍기 위치 및 용량 최적화에 관한 연구

김태권(T. K. Kim),하지수(J. S. Ha),박찬혁(C. H. Park) 한국에너지학회 2016 에너지공학 Vol.25 No.2

분사제트 온도변화에 따른 벽면충돌 현상에 대한 실험적 연구

최현훈(Hyeonhun Choi),우루노유미(Yumi Uruno),김상호(Sangho Kim),정재원(Jaewon Chung) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

In order to remove dissolved oxygen and carbon dioxide from feedwater in power generation facilities, boilers and incinerators, deaerators are essential. In actual deaerator, temperature of spray is about 145°C and the surrounding temperature is about 177°C (steam temperature). It is necessary to analyze the temperature in order to improve the efficiency of deaerator. In this paper, splashed fraction and jet breakup according to the distance from nozzle were studied. Also, Liquid film shapes on the vertical wall are visualized and analyzed using highspeed camera. These were obtained at different temperature respectively. As temperature increases, ξ(splashed fraction) becomes smaller overall. Also, the value of ξ<SUB>max</SUB>(maximum of splashed fraction) decreases as the temperature increases. The Rayleigh regime, the first wind-induced regime, and the second wind-induced regime were confirmed by jet breakup images. The phenomenon that <SUB>max</SUB> decreased with increasing temperature was visualized and confirmed. It was confirmed that the diameter of the liquid film becomes larger as the temperature rises. That is, ξ decreases because droplets spread on the wall and the thickness of the liquid film becomes thinner. Therefore, when the temperature of water rises, ξ decreases. The results of this paper are used to increase the efficiency of actual deaerator and provide data for design and optimization.

Influence of Deaeration, Cl− Ion and Strong Oxidizer on the Active Behavior of the High Phosphorus Containing Pig Iron and Subsequent Effect on the Sacrificial Anode Behavior

Nisheeth Kr. Prasad,A. S. Pathak,S. Kundu,K. Mondal 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

The effect of deaeration, Cl−ion content and strong oxidizer on the active behavior of the high phosphorus pig iron (HPPI)samples was studied in 3.5% NaCl and 1 N HNO3solutions. Deaerating the 3.5% NaCl solution could effectively shift thecorrosion potential of the HPPI below the protective potential of the steel in seawater [− 0.778 V vs saturated calomelelectrode (SCE)], which has not been observed in the freely aerated 3.5% NaCl solution. Both the Cl−ion content and thedeaerated conditions restrict the formation of the stable iron phosphate on the surface and promote the dissolution of the pigiron as soluble iron phosphate hydrate (FePO4·2H2O). However, in the case of the freely aerated nitric acid solution, evenwith deaeration, the HPPI samples have shown more noble behavior as compared to the mild steel due to the strong oxidizingnature of nitric acid and the formation of a stable iron phosphate on the surface.

세척 후 수침고목재의 물리.화학적 특성 변화

차미영,이광호,김윤수 한국문화재보존과학회 2006 보존과학회지 Vol.19 No.-

저습지에서 출토된 상수리나무를 재료로 세척에 따른 수침고목재 내 이물질의 제거 효과와 물리 화학적 특성 변화를 파악하였던 바 얻어진 결과는 다음과 같다. 수침고목재에 나타나는 대부분의 무기성분은 수침고목재가 매몰된 토양환경의 성분과 거의 동일하였다. 보존처리 현장에서 적용하고 있는 세척방법 즉, 도구법, 탈기법, EDTA법 및 초음파세척법을 적용하여 독립적 혹은 연속적 방법으로 수침고목재를 세척하였다. 독려세척의 경우 도구법에 의해 표면에 고착된 이물질이 효과적으로 제거되었고, EDTA 처리에 의해 표면 색상이 밝아졌다. 그러나 탈기법과 초음파에 의한 세척효과는 나타나지 않았다. 연속 세척의 경우 1단계 세척(도구법)은 독립세척과 동일한 효과를 얻었으며, 2단계 세척인 탈기법은 수침고목재 내에 있는 이물질을 제거하지 못했다. 탈기법이 무기물의 제거에는 적절하지 않았지만, 탈기 후 수침고목재가 균일화되어 치수안정제의 침투를 용이하게 하는 역할은 결코 무시할 수 없을 것으로 사료된다. 3단계 EDTA처리는 수침고목재 내의 철분(Fe)을 제거함으로써 수침고목재의 색상이 밝아지는 효과를 얻을 수 있었다. 4단계 세척은 3단계 세척시 목재 내에 잔류한 약품(Na)과 미세 이물질의 제거에 효과적이었다. Alteration of physical and chemical characteristics and the effect of removal of mineral substances in waterlogged archaeological woods by different cleaning processes were examined using oak wood(Quercus spp.) that was excavated from wetland near Gwangju, Korea. Cleaning methods employed in the present work were (1) tools, (2) deaeration, (3) EDTA and (4) ultrasonic cleaning, which are being currently applied in the field of preservation treatment. Cleaning process were performed independently or continuously. Composition of mineral substances in the waterlogged archaeological wood was almost same as the that of soil in which waterlogged archaeological woods were buried. In case of independent cleaning, tools cleaning efficiently removed the mineral substances on surface. Surface color become brighter after cleaning with EDTA. In contrast, deaeration and ultrasonic cleaning did not show any significant removal of mineral substances. In continuous cleaning process, tool cleaning as the first step treatment showed the same effect as shown in independent cleaning. Although deaeration as the second step cleaning did not remove the mineral substances, it could be assumed to contribute the infiltration of dimensional agents by homogenization of wood. EDTA treatment (the third step cleaning) removed the iron(Fe) and increased the whiteness of wood color. The ultrasonic treatment (the fourth step cleaning) removed the sodium(Na) remained after EDTA treatment and the fine mineral substances.