Current Issue : April - June Volume : 2019 Issue Number : 2 Articles : 5 Articles
Recompression supercritical carbon dioxide (SCO2) Brayton Cycle for the Chinese Initiative Accelerator Driven System (CiADS)\nis taken into account, and flexible thermodynamic modeling method is presented. The influences of the key parameters on\nthermodynamic properties of SCO2 Brayton Cycle are discussed and the comparative analyses on genetic algorithm and pattern\nsearch algorithm are conducted. It is shown that the cycle parameters such as turbine inlet temperature, pressure ratio, outlet\ntemperature at the hot end of condenser, and terminal temperature difference of regenerator 1 and regenerator 2 have significant\neffects on the cycle thermal efficiency. The calculation results indicate that pattern search algorithm has better optimization\nperformance and quicker calculating speed than genetic algorithm. The result of optimization of the parameters for CiADS with\nsupercritical carbon dioxide Brayton Cycle is 35.97%. Compared with other nuclear power plants of SCO2 Brayton Cycle, CiADS\nwith SCO2 Brayton Cycle does not have the best thermal efficiency, but the thermal efficiency can be improved with the reactor\noutlet temperature increases....
This paper presents capacity of the passive decay heat removal system (DHRS) operated under the natural circulation conditions to\nremove decay heat inside the main vessel of the Lead-bismuth eutectic cooled Fast Reactor (LFR). The motivation of this research\nis to improve the inherent safety of the LFR based on the China AcceleratorDriven System (ADS) engineering project. Usually the\nplant is damaged due to the failure of the main pumps and the main heat exchangers under the Station Blackout (SBO). To prevent\nthis accident, we proposed the DHRS based on the diathermic oil cooling for the LFR.The behavior of the DHRS and the plant was\nsimulated using the CFD code STAR CCM+ using LFR with DHRS. The purpose of this analysis is to evaluate the heat exchange\ncapacity of the DHRS and is to provide the reference for structural improvement and experimental design.The results show that\nthe stable natural circulations are established in both the main vessel and the DHRS. During the decay process, the heat exchange\npower is above the core decay heat power. In addition, in-core decay heat and heat storage inside the main vessel are efficiently\nremoved. All the thermal-hydraulics parameters are within a safe range. Moreover, the highest temperature occurs at the upper\nsurface of the core. A swirl occurs at the corner of the lateral core surface and some improvements should be considered. And\nthe natural circulation driving force can be further increased by reducing the loop resistance or increasing the natural circulation\nheight based on the present design scenario to enhance the heat exchange effect....
A Percolation reactor for the thermochemical pre-treatment of lignocellulosic\nbiomass as a precursor for the production of biofuel such as bioethanol from\ncomplex organic polymers is developed by this study. The reactor is designed\nto hold 3 kg of pulverised biomass of.........
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Image processing methods are increasingly used in civil engineering, especially in the\nmaintenance of concrete structures. Current digital cameras and post-processing methods allow\nverifying qualitatively the state of conservation of wide areas of concrete in dams and bridges.\nWhen dealing with building refurbishments and rehabilitation, it is important to verify that existing\nstructural elements fit the requirements of the standards; in the case of structures formed by traditional\nRC joists, cracking of the bottom-face provides information about the serviceability of these elements.\nThis research proposed and put in practice through experimental tests an image post-processing\nmethod for quantification of cracking (five specimens were used and calibrated). Based on a sequence\nof shots and through a complex step-by-step post-processing, cracks were identified and measured to\ncalibrate this method for real purposes. The method quantifies the crack opening width and spacing\nby analyzing the bottom-face of the joists through the shots. Measured values of crack spacing are\nvery similar to those predicted by the standards, while the values of crack opening width differ more\nfrom theoretical ones due to the scattering of results. However, the proposed method has been proved\nas suitable and useful for fast inspections of RC elements under bending....
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