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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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Novel flow behaviors induced by a solid particle in nanochannels: Poiseuille and Couette

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Chinese Science Bulletin 2014年第20期59卷 2478-2485页

作者： Cheng-Zhen Sun Wen-Qiang Lu Bo-Feng Bai Jie Liu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University College of Physical Sciences University of Chinese Academy of Sciences

We conducted a molecular dynamics(MD)simulation to address the novel flow behaviors induced by a solid particle in *** basic flows,i.e.,Poiseuille and Couette,are involved in this *** Poiseuille flow,the distribution of number density exhibits fluctuations in the center of channel and near the walls,which are caused by the strong interactions from the atoms of particle and *** stronger external driving forces,the fluid atoms move toward the center of channel and some cavities appear in the fluidic *** external driving forces and bigger particles make the fluid moving quickly in *** Couette flow,the particle rotates under the velocity difference among particle atoms in the shear *** fluid atoms near the walls become infrequent and move to the center of *** velocities of the centrally-located fluid atoms decrease owing to the particle,resulting in an untypical non-linear Couette *** summary,the solid particle brings new fluid–solid interface and interactions,which induce several novel behaviors in nanochannel flows.

关键词：流动行为纳米通道固体粒子 Poiseuille流诱发 Couette流强相互作用固体颗粒

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Hydrogen production by catalytic gasification of cellulose in supercritical water

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Frontiers of Chemical Science and engineering 2008年第2期2卷 176-180页

作者： Yu GUAN Aixia PEI Liejin GUO State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Cellulose,one of the important components of biomass,was gasified in supercritical water to produce hydrogen-rich gas in an autoclave which was operated batch-wise under high-pressure.K_(2)CO_(3) and Ca(OH)2 were selected as the catalysts(or promoters).The temperature was kept between 450uC and 500uC while pressure was maintained at 24–26 *** reaction time was 20 *** results showed that the two catalysts had good catalytic effect and optimum amounts were observed for each *** 0.2 g K_(2)CO_(3) was added,the hydrogen yield could reach 9.456 mol?kg21 which was two times of the H2 amount produced without *** 1.6 g Ca(OH)2 was added,the H2 yield was 8.265 mol?kg21 which is lower than that obtained using K_(2)CO_(3) as catalyst but is still 1.7 times that achieved without *** with the results obtained using K_(2)CO_(3) or Ca(OH)2 alone,the use of a combination of K_(2)CO_(3) and Ca(OH)2 could increase the H2 yield by up to 2.5 times that without catalyst and 25%and 45%more than that obtained using K_(2)CO_(3) and Ca(OH)2 alone,*** was found that methane was the dominant product at relatively low *** the temperature was increased,the methane reacts with water and is converted to hydrogen and carbon dioxide.

关键词： biomass hydrogen production supercritical water gasification hydrogen

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Research on control strategies for rapid load decrease events in fluoride salt reactor-supercritical CO2 Brayton cycle systems

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Nuclear engineering and Design 2025年 439卷

作者： Shichang, Yun Xinyu, Li Dalin, Zhang Ping, Song Wenxi, Tian Suizheng, Qiu Guanghui, Su State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Marine Thermal Power Technology Wuhan Second Ship Design and Research Institute Wuhan China

This study delves into the control strategies for the Fluoride-salt-cooled High-temperature Reactor-Supercritical CO2 (SCO2) Brayton cycle power generation system under rapid grid load reduction scenarios. By developing a dynamic simulation model, the system's dynamic response characteristics under rapid load changes were analyzed, and a combined control strategy emphasizing safety, speed, and economic efficiency was proposed. The research first compared the dynamic response characteristics and steady-state performance of different bypass configurations under load rejection conditions. The computational results indicate that all three bypass control systems exhibit excellent load-following capabilities, effectively responding to a 50 % load step change within 10 s. However, significant differences were observed in their steady-state thermodynamic performance: the upper cycle bypass control achieves the highest steady-state efficiency (η = 29.92 %), followed by the turbine bypass control (η = 27.50 %), with the heat source bypass control showing relatively lower efficiency (η = 26.49 %). Although the upper cycle bypass offers superior efficiency, it leads to a substantial increase in the working fluid flow through the compressor (ΔQ = 15 %) during operation, raising the risk of compressor blockage and necessitating additional flow restriction and anti-blocking interlock control systems. Considering system safety, control complexity, and engineering feasibility, the turbine bypass system, with its relative independence and lower operational risk, is deemed more suitable as the primary control strategy for load rejection conditions. Building on this, the study proposes a combined control strategy that leverages the strengths of both bypass control and inventory control. During the initial phase of rapid load reduction, the bypass control system quickly adjusts the turbine bypass valve opening to promptly respond to grid load changes, ensuring system frequency stability

关键词： Frequency stability

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Chlorine anchored pyrrole-based conjugated porous polymers for ultrahigh capacity and selective Hg(II) capture

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Separation and Purification Technology 2025年

作者： Bianyan He Jiarui Zhang Yubing Wang Mingtao Li Wei Yan Department of Environmental Science and Engineering Xi’an Key Laboratory of Solid Waste Recycling and Resource Recovery Xi’an Jiaotong University Xi’an 710049 PR China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 PR China

In this study, chlorine anchored pyrrole-based conjugated porous polymers (CPPs) with distinct pore properties were synthesized using the Knoevenagel reaction and the double chain condensation method. The partially crosslinked and partially oxidized structures of the materials exhibit a unique microstructure integrating interconnected nets and molecular hooks. This architecture utilizes pore channels for physical interception of Hg(II), while synergistic chemical immobilization at N, O, and Cl active sites enables multifunctional enhancement of Hg(II) capture efficiency. Among these materials, the maximum adsorption capacity reached 1183 mg·g −1 , demonstrating ultrahigh selectivity. Moreover, the adsorbents maintained > 90 % removal efficiency over 10 adsorption–desorption cycles, confirming excellent reusability. Mechanistic studies revealed that Hg(II) adsorption primarily whin material pores through hydrogen bonding and coordination interactions, and their synergistic interactions. This work highlights the efficiency of the double chain condensation design strategy in advancing conjugated porous polymers for the removal of heavy metals, particularly Hg(II), from wastewater.

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Proposal and thermodynamic analysis of a steam methane reforming system integrated with thermochemical energy storage and a SCO₂ brayton cycle

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Journal of Energy Storage 2025年 127卷

作者： Fu, Yu Liu, Ming Wang, Zhu Xie, Tao Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Institute of Industrial Catalysis School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an 710049 China

Solar energy is a promising alternative to fossil fuels for providing heat in steam methane reforming (SMR) hydrogen production. However, the variability of solar energy requires effective storage solutions. This study presents a new SMR hydrogen production system that integrates thermochemical energy storage (TCES) utilizing a CaO/CaCO₃ cycle with a SCO₂ Brayton cycle. The system converts fluctuating solar energy into the stable chemical energy of CaO by calcinating CaCO₃ in the solar calciner, with the SMR reaction mainly heated by the exothermic reaction of CaO and CO₂. The SCO₂ Brayton cycle efficiently recovers heat from the high-temperature SMR products. Comprehensive thermodynamic analysis and evaluation models are developed. Results show that the proposed system performs well, achieving energy and exergy efficiencies of 73.49 % and 78.46 %, respectively, under benchmark conditions. The energy storage efficiency of TCES is 81.55 %, and the solar-to-chemical energy efficiency is 48.21 %. Integrating TCES significantly enhances the system's steady operation under fluctuating solar energy conditions. The calciner accounts for the largest share of exergy destruction at 31.63 %, followed by the carbonator at 17.50 %. Sensitive analyses of key operating parameters indicate that higher CaO conversion rate and storage temperature enhance energy storage, energy, and exergy efficiencies. Besides, the energy and exergy efficiencies decrease with the increasing SMR reaction pressure but increase with rising reaction temperature. When the S/C is 2.0, these efficiencies reach their maximum values of 75.42 % and 78.63 %, respectively. © 2025 Elsevier Ltd

关键词： Hydrogen production SCO2 Brayton cycle Solar energy Steam methane reforming Thermochemical energy storage

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Flame mode transitions in outer recirculation zone of lean premixed prevaporized n-decane/air swirling flames

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Experimental Thermal and Fluid Science 2025年 168卷

作者： Lin, Wenjun Zhang, Weijie Liu, Hongfang Gao, Zhihao Cai, Xiao Wang, Jinhua Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development Center Mianyang621000 China

The outer recirculation zone (ORZ) flame modes and their transition were experimentally investigated in lean premixed prevaporized n-decane/air swirling flames. The flame structure and flow field were measured employing simultaneous CH2O/OH-PLIF and OH-PLIF/PIV laser diagnostics. The ORZ temperature was estimated with thermocouples. Three ORZ flame modes were identified: (1) mode II, characterized by extensive CH2O but nearly absent OH in the ORZ;(2) mode III, with flickering CH2O and OH in the ORZ;(3) mode IV, with flickering OH in the ORZ but nearly without CH2O. Besides, the mode I is defined as the inner shear layer (ISL) flame and mode V is the ISL/outer shear layer (OSL) flame. A theoretical diagram from mode I to V is achieved describing transition from the ISL to ISL/OSL flames. It is confirmed that the presence of CH2O in the ORZ results from the first-stage low-temperature autoignition, which is validated to be predictable with the ignition Damköhler number (Daig) after examining the fluid residence time and ignition delay time. It is found that the high-temperature ORZ flame indicated by the flickering OH radicals cannot be predicted merely using Daig. Instead, the increased flame speed and intensified ISL flame propagation into the ORZ due to the elevated equivalence ratio influence a lot, which can also be promoted by the shear layer vortices. These processes are expected to motivate the entrainment of hot burnt gas into the ORZ thus to form the high-temperature ORZ flame. The flickering ORZ flame is undesirable due to the potentially induced combustion instabilities, and this work can broaden its understanding and provide insights for its suppression. © 2025 Elsevier Inc.

关键词： Thermocouples

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High tension cyclic hydrocarbons synthesized from biomass-derived platform molecules for aviation fuels in two steps

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Green Energy & Environment 2023年第1期8卷 331-337页

作者： Zhanchao Li Yizhuo Wang Qing Li Liqing Xu Hong Wang Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an710054China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710054China

Synthesizing ring structure aviation fuels from biomass-derived platform molecules is challenging,especially for bridged ring structure aviation fuels which are typically achieved from fossil-derived ***,we report the synthesis of a series of ring structure biofuels in two steps by a combination of a solvent-free Michael-cyclization reaction and a hydrodeoxygenation(HDO)reaction from lignocellulosederived 5,5-dimethyl-1,*** biofuels are obtained with high overall yields up to 90%,which exhibit high densities of 0.81 g cm^(-3)-0.88 g cm^(-3)and high volumetric neat heat of combustion(VNHOC)values of 36.0 MJ L^(-1)-38.6 MJ L^(-1).More importantly,bridged-ring structure hydrocarbons can also be achieved in two steps by a combination of a Robinson annulation reaction and an HDO reaction to afford the final products at high overall yields up to 90%.The bridged-ring structure products have comparable high densities and high VNHOC values to the best artificial fuel JP-10(0.94 g cm^(-3)and 39.6 MJ L^(-1)).The results demonstrate a promising way for the synthesis of high-density aviation fuels with different fuel properties at high yields.

关键词： Biofuels 5,5-Dimethyl-1,3-cyclohexanedione Solvent-free Michael-cyclization Robinson annulation Green reaction

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Experimental Study of Drop Deformation and Breakup in Simple Shear flows

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Chinese Journal of Chemical engineering 2007年第1期15卷 1-5页

作者：林长志郭烈锦 State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University

The experimental results of the deformation and breakup of a single drop immersed in a Newtonian liq-uid and subjected to a constant shear rate which generated by counter rotating Couette apparatus were presented in this paper. From experimental observations, the breakup occurred by three mechanisms, namely, necking, end pinching, and capillary instability. Quantitative results for the deformation and breakup of drop are presented. The maximum diameter and Sauter mean diameter of daughter drops and capillary thread radius are linearly related to the inverse shear rate and independent of the initial drop size, the dimensionless wavelength which is the wave-length divided by the thread width at breakup is independent of the shear rate and initial drop size, and the deforma-tion of threads follows a pseudo-affine deformation for Cai/Cac larger than 2.

关键词： drop deformation breakup Couette shear flow

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Gas flow in a Stratified Porous Medium with Crossflow

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Journal of Thermal Science 2002年第1期11卷 35-40页

作者： Sun Hedong Gao Chengtai Qian Huanqun Zhou Fangde State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049China Department of Petroleum Engineering Xi’an Petroleum InstituteXi’an 710065China

A new model called semi-permeable wall model is presented for multilayer gas reservoir. The model is used to study the influence of crossflow on pressure transient well tests and other single-phase flow problems. It is suggested here to use this model to approximate the actual multilayer gas reservoir, so that the problem is greatly simplified mathematically. Its differential equation is established here for multilayer gas reservoirs, and is linearized by normalized pseudo pressure and pseudo time. Simulation program is developed by finite-difference method when all layers are perforated. The feature of wellbore pressure and rate is clarified by analyzing the results of numerical simulation.

关键词： multi-layer gas reservoir semi-permeable wall model numerical simulation transient well-test wellbore storage skin factor.

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