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고압형 급수가열기 동체 감육 완화를 위한 추기노즐 주변의 유동특성 연구
서혁기(Hyuk-Ki Seo),김윤신(Yoon-Shin Kim),김경훈(Kyung-Hun Kim),황경모(Kyeong-Mo Hwang) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-
Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle-installed downstream of the high pressure turbine extraction stream line inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. This paper describes operation of experience and numerical analysis composed similar condition with real high pressure feedwater heater. This study applied several impingement baffle plates to feedwater heater same as previous study. In addition, it shows difference of pressure distribution and value between single phase and two phase based on experience and numerical analysis.
저압 급수가열기 추기노즐 주변 동체의 감육 완화에 관한 연구
서혁기(Hyuk Ki Seo),박상훈(Sang Hun Park),김형준(Hyung Jun Kim),김경훈(Kyung Hoon Kim),황경모(Kyeong Mo Hwang) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
The most components and piping of the secondary side of domestic nuclear power plants were manufactured carbon-steel and low-alloy steel. Flow accelerated corrosion leads to wall thinning (metal loss) of carbon steel components and piping exposed to the flowing water or wet steam of high temperature, pressure, and velocity. The feedwater heaters of many nuclear power plants have recently experienced sever wall thinning damage, which increases as operating time progress. Several nuclear power plants in Korea have also experienced wall thinning damage in the shell wall around the impingement baffle. This paper describes the comparisons between the numerical analysis results using the FLUENT code and the experimental results based on down-scaled experimental facility. The experiments were performed based on several types of impingement baffle plates which are installed in low pressure feedwater heater.
배관감육관리에 활용되는 CHECWORKS 프로그램의 열수력해석 방법론 검증에 관한 연구
서혁기 ( Hyuk Ki Seo ),황경모 ( Kyeong Mo Hwang ) 한국부식방식학회(구 한국부식학회) 2013 Corrosion Science and Technology Vol.12 No.2
In general, pipelines at nuclear power plants are affected by various types of degradation mechanisms and may be ruptured after gradually thinning. FAC (Flow-Accelerated Corrosion) is typical aging mechanism affecting the secondary side piping system. In Korea nuclear power plants, CHECWORKS program have been used for management of wall thinning damages. However, sometimes, CHECWORKS program shows wrong results at the stage of NFA (Network Flow Analysis) in case of complex pipelines. This paper describes the calculation results of pressure drop in a complex pipeline and single line by using the CHECWORKS program and the analysis results are compared with those of engineering calculation results including errors between them.
김형준(Hyung Joon Kim),박상훈(Sang Hoon Park),서혁기(Hyuk Ki Seo),김경훈(Kyung Hoon Kim),황경모(Kyung Mo Hwang) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damange, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle-installed downstream of the high pressure turbine extraction stream line- inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of the number 5 high pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes operation of experience and numerical analysis composed similar condition with real high pressure feedwater heater. This study applied squared, curved and new type impingement baffle plates to feedwater heater same as previous study. In addition, it shows difference of pressure distribution and value between single phase and two phase based on experience and numerical analysis.
오세홍(Se Hong Oh),황경모(Kyeong Mo Hwang),서혁기(Hyuk Ki Seo),윤훈(Hun Yun),손성만(Sung Man Son),최청열(Choeng Ryul Choi) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
Liquid droplet impingement erosion (LDIE) is caused by continued exposure to impact by liquid droplets on solid surface. LDIE could be regarded as one of the major causes of unexpected troubles occasionally occurred in the inner bent pipe surface. Therefore, evaluating LDIE is an important topic of the thermal hydraulics and structural integrity in aging and life extension for nuclear power plants. In this study, first, several thinning rate correlations are reviewed and compared. And then, LDIE phenomenon in steam piping systems containing liquid droplets is simulated by using fluidstructure interaction (FSI) approach. Wall thinning phenomenon due to LDIE is presented as wall deformation in FSI approach. From the simulation, wall thinning depth is calculated. As wall thinning progressed, flow direction, droplet trajectory, and impact angle change with exposure time due to shape deformation of target wall. Therefore, it is important to consider the deformation of wall shape for accuracy.