Experiments were conducted in a constant volume bomb filled with isooctane/n-butanol blend-air mixtures over a wide range of n-butanol blending ratios, equivalence ratios, and initial pressures. High-speed schlieren p...
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Experience gained in decades of nuclear safety research and previous nuclear accidents direct to the investigation of passive safety system design and accident-tolerant fuel (ATF) system which is now becoming a hot re...
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Experience gained in decades of nuclear safety research and previous nuclear accidents direct to the investigation of passive safety system design and accident-tolerant fuel (ATF) system which is now becoming a hot research point in the nuclear energy field. The ATF system is aimed at upgrading safety characteristics of the nuclear fuel and cladding in a reactor core where active cooling has been lost, and is preferable or comparable to the current UO 2 –Zr system when the reactor is in normal operation. By virtue of advanced materials with improved properties, the ATF system will obviously slow down the progression of accidents, allowing wider margin of time for the mitigation measures to work. Specifically, the simulation and analysis of a large break loss of coolant accident (LBLOCA) without ECCS and extended station blackout (SBO) severe accident are performed for a pressurized water reactor (PWR) loaded with ATF candidates, to reflect the accident-tolerance of ATF.
The influence of γ-Al2O3/FC-72 nanofluids on pooling boiling heat transfer with a smooth surface was experimentally investigated. The fluorocarbon surfactant FSO-100 was also used in the experiment. In order to disti...
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The influence of γ-Al2O3/FC-72 nanofluids on pooling boiling heat transfer with a smooth surface was experimentally investigated. The fluorocarbon surfactant FSO-100 was also used in the experiment. In order to distinguish the effects of surfactant, four groups of contrast tests were designed as follows: base fluids (FC-72), base fluids with nanoparticles (γ-Al2O3+FC-72), base fluids with surfactant (FC-72+FSO-100) and nanofluids with surfactant (γ-Al2O3/FC-72+FSO-100). The results of nanofluids with surfactant showed that the heat transfer performance is enhanced compared with base fluid, but will weaken with the increase of particle concentration. In general, nanofluids can enhance the boiling heat transfer to some extent, and the enhancement is affected by the adjunction of surfactant and the sedimentation of nano-particules. Nanofluids prepared with only nanoparticles were not stable due to nonuniform distribution of the particles. The adjunction of surfactant (without nanoparticules) will lead to a significant deterioration in both heat transfer coefficient and CHF (Critical Heat Flux), but it can keep nanofluids stable and homogeneous to some degree for heat transfer enhancement.
In a novel bio-electrochemical system (BES) for hydrogen and electricity co-production with acetate substrate, the anolyte pH and cathode Pt loading effects are investigated to improve the cell performance for hydroge...
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Ignition delays of four typical syngas mixtures were investigated using both experimental and simulated methods. The shock tube experiments were conducted behind the reflected shock waves at temperature ranges from 87...
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TWR can make use of non-enriched fuel and obtain very high burnup without the need of fuel reprocessing. TWR is an effective way of fuel utilization besides the closed fuel cycle. In this paper, the feasibility of MA ...
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The paper describes a method for monitoring CO2 leakage in geological carbon dioxide sequestration. A real time monitoring parameter, apparent leakage flux(ALF), is presented to monitor abnormal CO2 leakage, which can...
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The paper describes a method for monitoring CO2 leakage in geological carbon dioxide sequestration. A real time monitoring parameter, apparent leakage flux(ALF), is presented to monitor abnormal CO2 leakage, which can be calculated by atmospheric CO2 and O2 data. The computation shows that all ALF values are close to zero-line without the leakage. With a step change or linear perturbation of concentration to the initial CO2 concentration data with no leakage, ALF will deviate from background line. Perturbation tests prove that ALF method is sensitive to linear perturbation but insensitive to step change of concentration. An improved method is proposed based on real time analysis of surplus CO2 concentration in least square regression process, called apparent leakage flux from surplus analysis(ALFs), which is sensitive to both step perturbation and linear perturbations of concentration. ALF is capable of detecting concentration increase when the leakage occurs while ALFs is useful in all periods of leakage. Both ALF and ALFs are potential approaches to monitor CO2 leakage in geosequestration project.
Structural integrity of steam generator should be maintained during operation, since it performs as the pressure boundary of primary side coolant. Localized thermal-hydraulic parameters of secondary side are essential...
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ISBN:
(纸本)9781632668264
Structural integrity of steam generator should be maintained during operation, since it performs as the pressure boundary of primary side coolant. Localized thermal-hydraulic parameters of secondary side are essential for the analysis of tube wastage, fatigue and failure. In this paper, a three-dimensional thermohydraulics analysis code, named STAF, is developed based on FLUENT. With STAF code, three-dimensional thermohydraulics of secondary side of AP1000 steam generator are generated. This code is developed based on the porous media theory. In this code, the drift flux two-phase model coupled with a simplified flow boiling model is utilized to present two-phase flow among the U-tube bundle. Downcomer, tube bundle, support plates and primary separators in steam generator are considered in STAF code. The calculated results are compared with a general steam generator thermohydraulic analysis code ATHOS, which is developed by the Westinghouse. The comparison indicates that STAF code performs well in evaluating thermal-hydraulic parameters in steam generator. The results show that the flow field varies significantly at different position in AP1000 steam generator. flow vapor quality at the inlet of primary separators varies significantly, which is a severe challenge to the capacity design of separators.
Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into Zn...
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Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into ZnO nanorod arrays for photoelectrochemical water splitting in visible light. X-ray diffraction (XRD) and X-ray photo-electron spectroscopy (XPS) results revealed that Cu^+ together with a small amount of Cu^2+ were highly dispersed within the ZnO nanorod arrays. The Cu ion doped ZnO nanorod arrays displayed extended optical absorption and enhanced photoelectrochemical performance under visible light illumination (A 〉 420 nm). A considerable photocurrent density of 18 μA/cm^2 at 0.8 V (vs. a saturated calomel electrode) was achieved, which was about 11 times higher than that of undoped ZnO nanorod arrays. This study proposes that ion implantation could be an effective approach for developing novel visible-light-driven photocatalytic materials for water splitting.
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