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Best estimate plus uncertainty analysis of the China advanced large-scale PWR during LBLOCA scenarios

International Journal of Advanced Nuclear Reactor Design and Technology 2020年 2卷 34-42页

作者： Chang, Yuhao Wang, Mingjun Zhang, Jing Tian, Wenxi Qiu, Suizheng Su, G.H. Department of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

China advanced large-scale Pressurized Water Reactor (PWR) implements series of passive safety systems to provide core cooling and decay heat removal in case of some unexpected accidents. The development of reactor best estimate system analysis codes has realized the transition from conservative safety analysis to Best Estimate plus Uncertainty (BEPU) analysis for the purpose of achieving more realistic results and digging larger safety margins. The BEPU analysis during Large Break Loss of Coolant Accident (LBLOCA) has been widely used for the licensing application of Nuclear Power Plants (NPPs). In this paper, the BEPU analysis of China advanced large-scale PWR was performed under the conditions of LBLOCA scenarios employing RELAP5 code. The models of reactor coolant system with all the passive safety systems were established and the influence of uncertainties of important parameters on the Peak Cladding Temperature (PCT) was evaluated. The results show the obtained PTC (1314 K) through the BEPU analysis is far below the 10CFR50.46 PCT acceptance criteria (1477 K) in case of LBLOCA and is also lower than the conservative calculation value (1348 K), indicating a larger safety margin. This work provides a meaningful evaluation method for China advanced large-scale PWR safety assessment. © 2020 Xi'an Jiaotong University

关键词： Pressurized water reactors

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Evaluation of R513A as an environmentally friendly alternative to R134a in spray cooling for laser surgery: Heat transfer performance and optimization

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International Journal of Thermal Sciences 2025年 215卷

作者： He, Zhi-Zhong Lin, Xiang-Wei Li, Chen-Xi Kong, Chen Shen, Lin-Xin Zhou, Zhi-Fu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China School of Future Technology Xi'an Jiaotong University Shaanxi Xi'an710049 China Xi'an Jiaotong University Health Science Center Shaanxi Xi'an710049 China

Spray cooling plays a pivotal role in mitigating thermal injuries to the epidermis during laser surgery. However, the widespread use of R134a, a refrigerant with a high global warming potential (GWP) of 1300, poses significant environmental concerns. In this study, R513A, a more environmental-friendly cryogen with a GWP of 573, is used to investigate the feasibility of replacing R134a and the effects of spray height, spurt duration, nozzle orifice diameter, and spray pressure on R513A spray cooling through a self-built open-loop spray system. Experimental results demonstrate that R513A exhibits superior cooling performance, achieving a minimum surface temperature (Tmin) 12 °C lower and a maximum heat flux (qmax) 27.5 % higher than R134a. Additionally, R513A offers a broader optimal spray height range (30–50 mm) in which Tmin is 4 °C and 13 °C lower than those at 20 mm and 10 mm, respectively. qmax in this range is 10 % and 16 % higher than those at 20 mm and 10 mm, respectively. While extending the spurt duration consumes more cryogen and prolongs the liquid film lifetime, the differences in Tmin and qmax are less than 4 °C and 10 kW/m2. With the nozzle orifice increasing from 0.6 mm to 1.0 mm, Tmin remains approximately −42 °C but qmax gradually increases by 6 kW/m2. Macroscopic analysis reveals that higher spray pressure induces a more dispersive spray, though this does not significantly improve cooling efficiency. To advance the understanding of R513A spray cooling dynamics, a dimensionless correlation was developed to predict the dynamic heat transfer coefficient across diverse conditions. This study not only highlights the potential of R513A as a sustainable alternative but also provides critical insights into optimizing spray cooling parameters for enhanced thermal management in laser surgery. © 2025 Elsevier Masson SAS

关键词： Chilling

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Accelerating electron transport in Eosin Y by bidentately bridging on BaSnO_(3)for noble-metal-free photocatalytic H 2 production

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Energy Storage and Saving 2023年第1期2卷 328-335页

作者： Jinwen Shi Huaiyu Lu Xing Kang Lulu Hou Feng Chen Yazhou Zhang Kang Chen Xiao Wang Xiangjiu Guan Lijing Ma International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an710049China State Key Laboratory for Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China Department of High-Tech Development Weichai Power Co.Ltd.WeifangShandong261061China China Petroleum Pipeline Engineering Co.Ltd. PipeChinaUrumqi830013China Department of New Energy Project Northwest Engineering Co.Ltd.PowerChinaXi’an710065China

The separation and transport of photogenerated carriers is regarded as a curial factor in photocatalytic H_(2)*** known in solar cells and photoelectron-chemistry,to strengthen the electron conduction for effective utilization of carriers,the electron transport material(ETM)is widely ***,inspired by the function of ETM,we adopted barium stannate(BaSnO_(3),labeled as BSO)as an excellent ETM which had the merits of high electron mobility,suitable conduction band position and simple preparation,to adjust the carrier kinetics of dye Eosin Y(EY)-sensitized photocatalytic ***,the photocatalytic system with the spatial sepa-ration sites of photogenerated carriers excitation and water reduction reaction was elaborately constructed,that was,dye EY-sensitized BSO(EY/BSO)for photocatalytic H_(2)*** photocatalytic H_(2)-production rate of EY/BSO(257𝜇mol·h^(−1)·g EY^(−1))in the absence of noble metals was 28.6 times higher than that of single EY(∼9𝜇mol·h^(−1)·g EY^(−1))under visible-light *** systematic and comprehensive characterizations,the formed electron transport channel by the bidentate bridging of EY on BSO could accelerate the transfer of photogenerated electrons from EY to BSO,promoting the effective separation of photogenerated carriers for the enhanced pho-tocatalytic ***,the water reduction reaction for H_(2)production proceeded on the surface of BSO that acted as the H_(2)-evolution cocatalyst,avoiding the use of high-cost noble ***,based on the well-proved ETM-based concept in the EY/BSO system,La-doped BaSnO_(3)(LBSO)with better electron trans-port ability was adopted to construct EY/LBSO system(344𝜇mol·h^(−1)·g EY^(−1))which showed better photocatalytic activity than EY/BSO.

关键词： Electron transport material Photocatalytic hydrogen production Barium stannate Dye sensitization

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A novel mid-temperature chemical looping system with near-zero carbon emissions for hydrogen and power coproduction

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Energy 2025年 329卷

作者： Li, Yang Fang, Yu Liu, Mingkai Liu, Kai Gai, Zhongrui Shen, Yuanhui Zhang, Ruqi Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China International Research Center for Renewable Energy & State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Designing an efficient system for conversion of fossil fuel to hydrogen with lower environmental impact represents a promising strategy to meet the demands of a low-carbon future society. This study introduces an integrated chemical looping system combining hydrogen production and combustion for low-carbon fossil fuel conversion. The system achieves hydrogen production at 600 °C, significantly lower than conventional steam methane reforming (850 °C). Moreover, chemical looping combustion is employed to enable efficient CO2 capture. The proposed system is investigated from key reactions, system performance, and economic feasibility aspects. Experimental results show 80 % methane conversion, a hydrogen yield of 2.6 in the hydrogen production process, and nearly 100 % CO2 purity from purge gas combustion. Thermodynamic analysis reveals the energy and exergy efficiencies of 74.3 % and 68.9 %, surpassing the reference system by 3.6 % and 4.1 %, respectively. Economic assessment indicates a 10 % reduction in the levelized cost of hydrogen compared to the reference system. 1000 consecutive cycles confirm the outstanding stability of the oxygen carrier particles for the system. This study demonstrates the system's feasibility, cost-effectiveness, and potential for sustainable hydrogen production with minimal environmental impact, introducing a promising method for the efficient utilization of fossil fuels. © 2025 Elsevier Ltd

关键词： Differential thermal analysis

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Understanding the Reversal Dilution Effect of the Species Sampling in the Negative Temperature Coefficient Region

SSRN

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SSRN 2023年

作者： Wu, Yingtao Mai, Zhaoming Rao, Boxuan Liu, Jie Tang, Chenglong Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'An710049 China Department of Power Mechanical Engineering Beijing Jiaotong University Beijing100044 China

Species sampling during fuel autoignition can provide valuable insights in studying the chemical kinetic mechanism. Various species sampling techniques have been developed for speciation quantification in different reactors. However, unavoidable dilution in the physical sampling brings uncertainty to the measurements, particularly in the negative temperature coefficient (NTC) region where the effect of dilution remains unclear. To address this issue and improve measurement accuracy, numerical species samplings during the autoignition of n-butane mixture were studied in a rapid compression machine reactor. Results show that greater fuel consumption and intermediate generation were observed in regions with lower temperatures instead of the hot core zone. Therefore, the dilution effect on the sampling results is reversed inside the NTC region. Furthermore, results from two typical sampling methods were compared with the target core profiles to determine their uncertainties. Lastly, the feasibility of applying dilution ratio calibration on the sampling results in the NTC region was tested, which indicates the necessity of considering the NTC effect, particularly for intermediates with low concentrations. Alternatively, increasing the sampling duration of the fast-sampling method effectively reduces the uncertainty of species concentration and enhances the robustness of mechanism validation regardless of the NTC behavior. © 2023, The Authors. All rights reserved.

关键词： Temperature

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Room-temperature photodeposition of conformal transition metal based cocatalysts on BiVO4 for enhanced photoelectrochemical water splitting

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Nano Research 2020年第1期13卷 231-237页

作者： Lu Wang Tao Zhang Jinzhan Su Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringSchool of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an710049China

Photoelectrochemical(PEC)water splitting using semiconductors offers a promising way to convert renewable solar energy to clean hydrogen ***,due to the sluggish reaction kinetics of water oxidation,significant charge recombination occurred at the photoanode/electrolyte interface and cause decrease of its PEC *** reduce the surface recombination,we deposit different transition metal complexes on BiVO4 nanocone arrays by a versatile light driven in-situ two electrode photodeposition approach without applied *** cobalt phosphate“Co-Pi”,nickel borate“Ni-Bi”and manganese phosphate“Mn-Pi”complexes were deposited on BiVO4 nanocone arrays to form core-shell structure photoanode,all of which lead to enhanced photoelectrochemical *** photocurrent of the Co-Pi/BiVO4 photoanode under front-side illumination for 5 min is increased by 4 folds comparing to that of bare BiVO4 photoanode at 0.6 V ***,reaching a hole transfer efficiency as high as 94.5%at 1.23 V *** proposed photodeposition strategy is simple and efficient,and can be extended to deposite cocatalyst on other semiconductors with a valence band edge located at a potential more positive than the oxidation potential of transition metal ion in the cocatalyst.

关键词： bismuth vanadate photoelectrochemcial water splitting conformal photodeposition cocatalyst

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Hydrodynamic Pattern in Drying Saline Droplet with Suspended Nanoparticles

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Journal of Bionic Engineering 2020年第4期17卷 802-808页

作者： Junheng Ren Xin Zhong Lu Shen Fei Duan School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Evaporation of multicomponent droplets has gained much attention nowadays because of their complex flow fields and various deposition *** we observe strong flows in evaporating sodium chloride saline droplets with suspended alumina oxide *** evolution of flow pattern was studied by tracking the trajectories of particles and the velocity field was investigated with Particle Image Velocimetry *** non-uniform evaporation rate along the droplet surface leads to a concentration gradient which induces the convection *** the evaporation process before crystallization happens,evolution of the flow can be divided into two *** Regime I,a centrosymmetric convection recirculation is formed *** RegimeⅡ,the convection recirculation migrates to the droplet edge and evolves into several small *** the late evaporation stage,crystallization could induce strong convection *** is shown that the flow tends to become more chaotic with a lower salt concentration.

关键词： convection flow concentration gradient saline droplet crystallization

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Thermodynamic Analysis and Optimization of Two-Step Supercritical Water Desorption-Gasification System of Oily Sludge

SSRN

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SSRN 2024年

作者： Zhang, Chenghao Wang, Gaoyun Zhao, Qiuyang Gao, Yunbo Ge, Zhiwei Jin, Hui Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No. 28 Xianning West Road Xi’an710049 China Technical Inspection Center Sinopec Shengli Oilfield Company Dongying257000 China

The two-step supercritical water desorption-gasification (TSSCWDG) technology can significantly improve the gasification efficiency of oil sludge. However, few works have been conducted to explore the influence of operating parameters on this process. In this paper, a novel desorption-gasification process modeling was constructed based on the supercritical water gasification (SCWG) of oily sludge and the influences of different operating parameters on the system efficiencies were investigated. Increasing the separation temperature and the desorption levels can achieve the rapid improvement of the efficiencies of the TSSCWDG system, but more desorption levels may increase the complexity of the system and the operating cost. The desorption temperature had a relatively small impact on the system efficiencies, but the lower desorption temperature was beneficial to the utilization of industrial waste heat and decreasing the operating cost. Moreover, the TSSCWDG system was optimized and analyzed, and the optimized system had achieved the energy matching between the gasification products and unites, resulting in significant reduction of the irreversible losses in each unit, which the energy efficiency of the optimized system reached 83.4%. This work could provide essential theoretical guidance for the scale-up and design of the industrial application of SCWG of oil sludge with hydrogen production. © 2024, The Authors. All rights reserved.

关键词： Desorption

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Experimental studies of ash film fractions based on measurement of cenospheres geometry in pulverized coal combustion

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Frontiers in Energy 2021年第1期15卷 91-98页

作者： Siqi LIU Yanqing NIU Liping WEN Yang LIANG Bokang YAN Denghui WANG Shi'en HUI State Key Laboratory of Multiphase Flow in Power Engineering Department of Thermal EngineeringSchool of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

In pulverized coal particle combustion, part of the ash forms the ash film and exerts an inhibitory influence on combustion by impeding the diffusion of oxygen to the encapsulated char core, while part of the ash diffuses toward the char core. Despite the considerable ash effects on combustion, the fraction of ash film still remains unclear. However, the research of the properties of cenospheres can be an appropriate choice for the fraction determination, being aware that the formation of cenospheres is based on the model of coal particles with the visco-plastic ash film and a solid core. The fraction of ash film X is the ratio of the measuring mass of ash film and the total ash in coal particle. In this paper, the Huangling bituminous coal with different sizes was burnt in a drop-tube furnace at 1273, 1473, and 1673 K with air as oxidizer. A scanning electron microscope (SEM) and cross-section analysis have been used to study the geometry of the collected cenospheres and the effects of combustion parameters on the fraction of ash film. The results show that the ash film fraction increases with increasing temperature and carbon conversion ratio but decreases with larger sizes of coal particles. The high fraction of ash film provides a reasonable explanation for the extinction event at the late burnout stage. The varied values of ash film fractions under different conditions during the dynamic combustion process are necessary for further development of kinetic models.

关键词： ash film fraction cenospheres coal combustion fly ash

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Development of typical processes and key devices for direct air CO2 capture

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Meitan Xuebao/Journal of the China Coal Society 2024年第10期49卷 4203-4221页

作者： Yu, Binpeng Tan, Lei Wang, Ding Wang, Limin Xiang, Xiaofeng Wang, Zhichao Jin, Zhonghua Yang, Bolun Wu, Zhiqiang School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an710049 China Shaanxi Province Energy and Chemical Process Intensification Key Laboratory Xi’an710049 China School of Engery and Powerl Engineering Xi’an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an710049 China Shaanxi Engineering Research Center if Coal Fired Boiler Environmental Protection Xi’an710054 China

Conventional carbon capture and storage technologies and carbon capture, utilization and storage technologies mainly target CO2 emissions from fixed sources, while direct air capture CO2 (DAC) technology, as an emerging negative carbon emission technology, can capture CO2 emissions from distributed sources and further reduce the global atmospheric CO2 concentration. In this paper, the development process of DAC's typical liquid absorption process, solid adsorption process and the construction of relevant demonstration projects are introduced, the technical characteristics of emerging DAC processes are analyzed, and the key equipment schemes and future development trends of existing DAC processes are discussed. The DAC liquid absorption process has the characteristics of low cost of absorbent raw materials and high selectivity, which can realize a large-scale continuous capture, but high energy consumption in the regeneration process. The DAC solid adsorption process has the characteristics of modularity, low investment cost, and relatively low energy consumption in the regeneration process, but requires a regular replacement of adsorption materials and maintenance of adsorption equipment, which is suitable for small-scale DAC application scenarios. Two typical DAC process absorption/adsorption materials are reviewed. In the DAC electric oscillation adsorption process, CO2 is chemically captured in the solid electrode, and CO2 desorption is achieved by changing the polarity of the solid electrode with applied electric field. This process has a higher efficiency than that of the heat or pressure-based separation process. The CO2 in the air is selected through the DAC separation membrane to achieve an efficient carbon capture. The DAC process achieves the CO2 absorption and desorption through the change of humidity, which breaks through the high energy consumption limit of conventional variable temperature/pressure swing adsorption. The DAC bio-absorption process absor

关键词： Adsorption

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