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연구용 원자로에서 자연대류 냉각 시 원자로구조물 유동의 전산유체역학 분석
박홍범(Hong Beom Park),박기정(Ki-Jung Park),정민규(Minkyu Jung),김성훈(Seong-Hoon Kim) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11
In an open pool type reactor, pool water is heat sink. When Primary Cooling System pump stops, decay heat is removed by natural circulation. In downward cooling research reactor, forced cooling is downward and natural circulation cooling is upward inside the reactor assembly. There is flow reversal between forced cooling and natural circulation cooling so Critical Heat Flux Ratio(CHFR) should be considered. In this research, natural circulation is calculated by Computational Fluid Dynamics(CFD) to analyze flow reversal in reactor assembly and flow reversal in reactor assembly is appeared between forced cooling and natural circulation cooling.
Variable force solenoid valve에서 flow force의 분석
박홍범(Hong Beom Park),성형진(Hyung Jin Sung),이기수(Gee Soo Lee),양갑진(Gab Jin Yang),이현우(Hyun Woo Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Three-dimensional numerical simulations were carried out to investigate the flow dynamic behavior and pressure characteristics of a variable force solenoid (VFS) valve used in automatic transmissions. To visualize the dynamic movement of the spool, a moving mesh with dynamic layering meshes for varying boundary conditions was employed. The VFS valve was characterized by determining the variation in the equivalent orifice area with the spool displacement. The pressure sensitivity was found to be precisely controlled by the relation between the depth and the area of the notch in the range of the characteristic length of the valve. The results of model C, which takes into account both seal leakage and notches, indicate that there are linear pressure sensitivities in the range of the valve overlap and that there are smooth pressure control characteristics in the range of the two notches.
박홍범(Hong Beom Park),성형진(Hyung Jin Sung) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
In this paper, analysis of pressure and flow characteristics have been performed with a servo valve. A number of servo valve have been used in various applications including the inserting device, bearing transportation and welding machine. By analysis of flow and pressure gradient, technology can be obtained about optimal simulation of high response servo valve for competitiveness. Spool displacement and ratio of inlet/outlet pressure can give big effects to flow and pressure inside servo valve.
박홍범(Hong Beom Park),서경우(Kyeongwoo Seo),김성훈(Seong Hoon Kim) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
In an open pool type research reactor, the pool water has a role of the ultimate heat sink and behaves as a shielding barrier for the reactor core and the spent fuel. So guaranteeing the pool water inventory to be more than a minimum level is important tasks in research reactor. If the components of primary cooling system are below the core level, siphon break valves are needed to guarantee the poo water inventory. The performance of siphon break is dependent on the size of siphon break valve. To decide the size of siphon break valve, computational fluid dyanamics is carried out by commercial code. In this study, the comparison of Fluent and CFX is studied in siphon break.
전산유체역학을 이용한 연구용 원자로에서의 자연대류 연구
박홍범(Hong Beom Park),정민규(Minkyu Jung),박기정(Ki-Jung Park),서경우(Kyoung Woo Seo) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
In an open pool type reactor, pool water is used as heat sink. When Primary Cooling System pump stops, flap valves open and decay heat is removed by natural circulation. Nuclear safety analysis code is mostly one-dimensional so it is not easy to analyze three dimensional natural circulation. Evaluating natural circulation using experiment is hard to a point of view space, time and cost. So in this research, natural circulation is analyzed by Computational Fluid Dynamics(CFD) using commercial code. Due to many complicated structures in a reactor pool, simplification is needed. A cell in fuel assembly is modeled and porous model in a cell is modeled. Natural circulation of CFD about porous model in a cell and real cell structure is compared.