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Numerical analysis of transient pressure variation in the condenser of a nuclear power station
Xinjun Wang,Zijie Zhou,Zhao Song,Qiankui Lu,Jiafu Li 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.2
To research the characteristics of the transient variation of pressure in a nuclear power station condenser under accident condition, a mathematical model was established which simulated the cycling cooling water, heat transfer and pressure in the condenser. The calculation program of transient variation characteristics was established in Fortran language. The pump’s parameter, cooling line’s organization, check valve’s feature and the parameter of siphonic water-collecting well are involved in the cooling water flow’s mathematical model. The initial conditions of control volume are determined by the steady state of the condenser. The transient characteristics of a 1000 MW nuclear power station’s condenser and cooling water system were examined. The results show that at the condition of plant-powersuspension of pump, the cooling water flow rate decreases rapidly and refluxes, then fluctuates to 0. The variation of heat transfer coefficient in the condenser has three stages: at start it decreases sharply, then increases and decreases, and keeps constant in the end. Under three conditions (design, water and summer), the condenser pressure goes up in fluctuation. The time intervals between condenser’s pressure signals under three conditions are about 26.4 s, which can fulfill the requirement for safe operation of nuclear power station.
Shaoheng Li,Ziji Bai,Feiyang Rong,Jiayin Huang,Lipan Zhou,Guodong Feng,Zhiguang Song 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-
Palladium-catalyzed coupling reactions have become effective tools for forming new carbon–carbonbonds. In this work, a novel fluorescence active benzotriazole-coumarin derivative, (E)-N’-((1H-benzo[d][1,2,3]triazol-6-yl)methylene)-7-(diethylamino)-2-ox o-2H-chromene-3-carbohydrazide (BTANC),was synthesized as ligand in Pd(II) cation coordination. It is shown that BTANC has a strong fluorescentemission at 483 nm and Pd(II) can effectively quench the fluorescence of BTANC and BTANC shows excellentsensitivity and selectivity towards Pd (II) ions. Otherwise, the BTANC-Pd(II) complex was also testedin the Sonogashira coupling reaction of phenylacetylene and aryl halides. The desired product wasobtained with high yield (up to 99%) under the optimized reaction conditions. More to that, Low fluorescenceemission was observed during the Pd-catalyzed reaction process and the fluorescent emission ofBTANC was recovered at the end of the Pd-catalyzed reaction because the oxidative addition of the arylhalide towards Pd (0) was shut down at the end of the Pd-catalyzed reaction. This fluorescence propertiesof BTANC indicates the feasibility of using fluorescence signal as a potential tool to monitor the completionof the Sonogashira coupling reaction.
Wang Xinjun,Cheng Peng,Xie Jinwei,Zhou Zijie 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.8
The present paper investigated the enhancement of moisture-separation efficiency for ordinary special crossunder pipe separators(SCRUPSs) and proposed three structure-modified separators (combined separator, Z-shaped SCRUPSs, and spiral-type SCRUPSs). Deposition mechanisms for droplets with different sizes were considered using commercial CFD flow solver. Results show that threestructuremodified separators can increase droplet deposition rate to varying degrees. Regarding flow losses, spiral-type SCRUPSs causethe highest increase, with a total pressure loss coefficient of 231%, although it has the best deposition rate improvement. Among the threestructure-modified separators, "Z" shape separator has the best separation performance because of its higher moisture-separation efficiencyand lower total pressure loss efficiency. Results could provide theoretical basis for research on and development of this new typeof moisture separator.