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Oxidation Behaviors of Different Grades of Ferritic Heat Resistant Steels in High-Temperature Steam and Flue Gas Environments

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Acta Metallurgica Sinica(English Letters) 2022年第7期35卷 1103-1116页

作者： Xiaogang Li Qu Liu Shanlin Li Yu Zhang Zhipeng Cai Kejian Li Jiluan Pan Department of Mechanical engineering Tsinghua UniversityBeijing 100084China key laboratory for advanced Materials Processing technology Ministry of EducationBeijing 100084China State key laboratory of Tribology Tsinghua UniversityBeijing 100084China collaborative innovation center of advanced nuclear energy technology Tsinghua UniversityBeijing 100084China

For steam tubes used in thermal power plant,the inner and outer walls were operated in high-temperature steam and flue gas environments *** this study,structure,microstructure and chemical composition of oxide films on inner and outer walls of exservice low Cr ferritic steel G102 tube and exservice high Cr ferritic steel T91 tube were *** oxide film was composed of outer oxide layer,inner oxide layer and internal oxidation *** outer oxide layer on the original surface of tube had a porous structure containing Fe oxides formed by diffusion and oxidation of *** specially,the outer oxide layer formed in flue gas environment would mix with coal combustion products during the growth *** inner oxide layer below the original surface of tube was made of Fe–Cr *** internal oxidation zone was believed to be the precursor stage of inner oxide *** formation of internal oxidation zone was due to O diffusing along grain boundaries to form *** were Fe–Cr–Si oxides discontinuously distributed along grain boundaries in the internal oxidation zone of G102,while there were Fe–Cr oxides continuously distributed along grain boundaries in that of T91.

关键词： Ferritic heat resistant steels High temperature service Oxide layer Steam Flue gas Oxidation evolution

Adaptive output-feedback power-level control for modular high temperature gas-cooled reactors

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Chinese Journal of Chemical engineering 2015年第12期23卷 2092-2097页

作者：董哲 institute of nuclear and new energy technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua University

Small modular reactors(SMRs) are beneficial in providing electricity power safely and viable for specific applications such as seawater desalination and heat production. Due to its inherent safety feature, the modular high temperature gas-cooled reactor(MHTGR) is considered as one of the best candidates for SMR-based nuclear power plants. Since its dynamics presents high nonlinearity and parameter uncertainty, it is necessary to develop adaptive power-level control, which is beneficial to safe, stable, and efficient operation of MHTGR and is easy to be implemented. In this paper, based on the physically-based control design approach, an adaptive outputfeedback power-level control is proposed for MHTGRs. This control can guarantee globally bounded closedloop stability and has a simple form. Numerical simulation results show the correctness of the theoretical analysis and satisfactory regulation performance of this control.

关键词： High temperature gas-cooled reactor Power-level regulation Adaptive control

Third generation of vortex identification methods:Omega and Liutex/Rortex based systems

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Journal of Hydrodynamics 2019年第2期31卷 205-223页

作者： Chaoqun Liu Yi-sheng Gao Xiang-rui Dong Yi-qian Wang Jian-ming Liu Yu-ning Zhang Xiao-shu Cai Nan Gui Department of Mathematics University of Texas at ArlingtonArlington 76019TexasUSA College of energy and Power engineering University of Shanghai for Science and TechnologyShanghai 200093China School of Aerospace engineering Tsinghua UniversityBeijing 100084China School of Mathematics and Statistics Jiangsu Normal UniversityXuzhou 221116China key laboratory of Condition Monitoring and Control for Power Plant Equipment(ministry of education. School of EnergyPower and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China institute of nuclear and new energy technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China

A vortex is intuitively recognized as the rotational/swirling motion of fluids,but a rigorous and universally-accepted definition is still not *** tube/filament has been regarded equivalent to a vortex since Helmholtz proposed the concepts of vorticity tube/filament in 1858 and the vorticity-based methods can be categorized as the first generation of vortex identification *** the last three decades,a lot of vortex identification methods,including 0,A,and Aci criteria,have been proposed to overcome the problems associated with the vorticity-based *** of these criteria are based on the Cauchy-Stokes decomposition and/or eigenvalues of the velocity gradient tensor and can be considered as the second generation of vortex identification *** from 2014,the Vortex and Turbulence Research Team at the university of Texas at Arlington(the UTA team)focus on the development of a new generation of vortex identification *** first fruit of this effort,a new Omega(/2)vortex identification method,which defined a vortex as a connected region where the vorticity overtakes the deformation,was published in *** 2017 and 2018,a Liutex(previously called Rortex)vector was proposed to provide a mathematical definition of the local rigid rotation part of the fluid motion,including both the local rotational axis and the rotational ***/Rortex is a new physical quantity with scalar,vector and tensor forms exactly representing the local rigid rotation of ***,a decomposition of the vorticity to a rotational part namely Liutex/Rortex and an anti-symmetric shear part(RS decomposition)was introduced in 2018,and a universal decomposition of the velocity gradient tensor to a rotation part(7?)and a non-rotation part(NR、was also given in 2018 as a counterpart of the traditional Cauchy-Stokes *** in early 2019,a Liutex/Rortex based Omega method called Omega-Liutex,which combines the respective advantages o

关键词： Vortex definition vortex identification Omega Liutex/Rortex direct numerical simulation turbulence

Temperature analysis of the HTR-10 after full load rejection

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nuclear Science and Techniques 2019年第11期30卷 127-138页

作者： Xiang-Cheng Zhang Ding She Fu-Bing Chen Lei Shi Yu-Jie Dong Zuo-Yi Zhang institute of nuclear and new energy technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety Ministry of Education Tsinghua University

The HTR-10 is a small modular high-temperature reactor located in tsinghua university,in *** the reactor ran continuously for 72 h at full power in the commissioning stage,a full load rejection test was conducted by manually disconnecting the generator from the *** this study,reactor transients were analyzed using the THERMIX *** of the important thermal–fluid phenomena that occurred after the test initiation are discussed here,including the natural convection of helium in the core and the temperature redistribution in the *** reproduced for the measuring points arranged in the internals were in agreement with the test *** demonstrated that the code and calculation model are suitable for posttest analysis *** the safety features of the reactor,there was a large margin between the predicted maximum fuel temperature of 997℃and the safety limit of 1620℃.

关键词： HTR-10 Load rejection THERMIX Code validation

Microstructure and high temperature fracture toughness of NG-TIG welded Inconel 617B superalloy

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Journal of Materials Science & technology 2020年第4期39卷 173-182页

作者： Xiaogang Li Kejian Li Shanlin Li Yao Wu Zhipeng Cai Jiluan Pan Department of Mechanical engineering Tsinghua UniversityBeijing100084China State key laboratory of Tribology Tsinghua UniversityBeijing100084China collaborative innovation center of advanced nuclear energy technology Tsinghua UniversityBeijing100084China tsinghua university Research institute for advanced Equipment Tianjin300304China

In the present study,the microstructure,fracture toughness,and fracture behavior of Inconel 617 B narrow gap tungsten inert gas(NG-TIG)welded joint were investigated systematically at the designed service temperature of 700℃.Fracture toughness(J0.2)of base metal(BM)and heat affected zone(HAZ)was higher than that of weld metal(WM).In HAZ and BM,strain mainly loc alised at grain boundaries with large misorientation and there were lots of coincidence site lattice(CSL)∑3 boundaries related to twins inside grains,which led to the much higher fracture toughness of BM and HAZ than *** high numbers of twins as well as the less serious strain localization at grain boundaries resulted in the most outstanding fracture toughness of BM.

关键词： Nickel alloys Welding Fracture behavior Microstructure Misorientation

Oxidation damage and interfacial failure of dissimilar metal welds containing ferritic heat resistant steels

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Journal of Iron and Steel Research International 2021年第11期28卷 1439-1450页

作者： Xiao-gang Li Zhi-peng Cai Xin Chen Shu-qing Dong Wen-he Cai Yu Zhang Shan-lin Li Ke-jian Li Shao-shi Rui Ji-luan Pan Department of Mechanical engineering Tsinghua UniversityBeijing 100084China key laboratory for advanced Materials Processing technology Ministry of EducationBeijing 100084China State key laboratory of Tribology Tsinghua UniversityBeijing 100084China collaborative innovation center of advanced nuclear energy technology Tsinghua UniversityBeijing 100084China China Datang Corporation Science and Technological Research institute Thermal Power Technology Research InstituteBeijing 100040China

The ex-service steam tubes containing dissimilar metal weld(DMW)between high Cr ferritic steel T91 and austenitic stainless steel TP347H and the ex-service steam tubes containing DMW between low Cr ferritic steel G102 and austenitic stainless steel TP347H were obtained from coal-fired thermal power plants in China,and their microstructures at the nickel-based weld metal(WM)/ferritic steel interfaces and oxidation characteristics were *** operating for 15,000 h at steam temperature of 541 C and steam pressure of 17.5 MPa,a G102/TP347H DMW failed along the WM/G102 steel interface,which was a dangerous premature failure mode without obvious plastic *** interfacial failure was attributed to the interaction between oxidation and cracking along the interface,where fracture appeared to be related with the strain concentration at the *** notch along the WM/G102 steel interface was the precursor of premature interfacial failure of DMW involving *** the DMW involving high Cr ferritic steel T91,ferritic steel side could form a Cr-rich passive film during service and thus would not be further oxidized after operating for 67,000 h at steam temperature of 541 C and steam pressure of 3.5 *** was concluded that oxidation played a more important role in failure of these DMWs,and retarding the development of oxidation and avoiding the interfacial oxide notch would dramatically improve the service performance of steam tubes containing DMWs.

关键词： Dissimilar metal weld Ferritic heat resistant steel Nickel-based weld metal Oxidation Interfacial failure High-temperature service

Modeling of dynamic recrystallization volume fraction evolution for AlCu4SiMg alloy and its application in FEM

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Transactions of Nonferrous Metals Society of China 2019年第6期29卷 1138-1151页

作者： Guo-zheng QUAN Rui-ju SHI Jiang ZHAO Qiao LIU Wei XIONG Hui-min QIU State key laboratory of Mechanical Transmission School of Material Science and Engineering Chongqing University Chongqing 400044 China institute of nuclear and new energy technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua University Beijing 100084 China

To improve the understanding of coupling effect between dynamic recrystallization(DRX)behaviors and flow behaviors of as-cast AlCu4 SiMg, a finite element(FE) simulation equipped with the models of DRX evolution was implemented. A series of isothermal compression tests were performed primarily on a Gleeble-3500 thermo-mechanical simulator in a temperature range of 648-748 K and a strain rate range of 0.01-10 *** to the measured true stress-strain data,the strain hardening rate curves(dσ/dε versus σ) were plotted to identify the critical strains for DRX initiation(εc). By further derivation of the related material constants, the DRX volume fraction equation and the strain for 50% DRX(ε0.5) equation were solved. Accordingly, the aforementioned DRX equations were implanted into the FE model to conduct a series of simulations for the isothermal compression tests. The results show that during the evolution of DRX volume fraction at a fixed strain rate, the strain required for the same amount of DRX volume fraction increases with decreasing temperature. In contrast, at a fixed temperature, it increases with increasing strain rate. Ultimately, the DRX kinetics model of AlCu4 SiMg alloy and the consequence of the FE analysis were validated by microstructure observations.

关键词： AlCu4SiMg alloy DRX kinetics model DRX volume fraction flow behavior

An all-optical phase detector by amplitude modulation of the local field in a Rydberg atom-based mixer

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Chinese Physics B 2022年第9期31卷 254-259页

作者： Xiu-Bin Liu Feng-Dong Jia Huai-Yu Zhang Jiong Mei Wei-Chen Liang Fei Zhou Yong-Hong Yu Ya Liu Jian Zhang Feng Xie Zhi-Ping Zhong School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China institute of Physics Chinese Academy of SciencesBeijing 100190China National Time Service Centre Chinese Academy of SciencesXi'an 710600ChinaUniversity of Chinese Academy of SciencesBeijing 100049China institute of nuclear and new energy technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China CAS center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

Recently,a Rydberg atom-based mixer was developed to measure the phase of a radio frequency(RF)*** phase of the signal RF(SIG RF)field is down-converted directly to the phase of a beat signal created by the presence of a local RF(LO RF)*** this study,we propose that the Rydberg atom-based mixer can be converted to an all-optical phase detector by amplitude modulation(AM)of the LO RF field;that is,the phase of the SIG RF field is related to both the amplitude and phase of the beat *** the AM frequency of the LO RF field is the same as the frequency of the beat signal,the beat signal will further interfere with the AM of the LO RF field inside the atom,and then the amplitude of the beat signal is related to the phase of the SIG RF *** amplitude of the beat signal and the phase of the SIG RF field show a linear relationship within the range of 0 toπ/2 when the phase of the AM is set with a differenceπ/4 from the phase of the LO RF *** minimum phase resolution can be as small as 0.6°by optimizing the experimental conditions according to a simple theoretical *** study will expand and contribute to the development of RF measurement devices based on Rydberg atoms.

关键词： quantum sensor phase detector Rydberg atoms micorwave electromagnetically induced transparency amplitude modulation

Dynamic Characteristics Analysis on MHTGR Plant’s Secondary Side Fluid Flow Network

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Journal of Power and energy engineering 2016年第7期4卷 15-22页

作者： Maoxuan Song Zhe Dong institute of nuclear and new energy technology Collaborative Innovation Center of Advanced Nuclear Energy Technology of China Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing China

Multipe NSSS (nuclear Steam Supply System) modules use the common feeding-water system to drive the common turbine power generation set. The SSFFN (secondary side fluid flow network) of MHTGR plant has features i.e. strong-coupling and nonlinearity. A wide range of power switching operation will cause unsteady flow, which may destroy the working elements and will be a threat for normal operation. To overcome those problems, a differential-algebraic model and PI controllers are designed for the SSFFN. In MATLAB\SIMULINK environment, a simulation platform is established and used to make a simulation of SSFFN of a MHTGR plant with two NSSS modules, which uses feedwater valves to control the mass flow rate in each module instead of feedwater pump. Results reflect good robustness of controllers.

关键词： MHTGR Plant Secondary Side Fluid Flow Network a Differential-Algebraic Model PI Controllers