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Coupled Axisymmetric Peridynamics with Stabilized Correspondence Material Model for Ablation and Fracture Problems

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SSRN 2024年

作者： Zhang, Hanbo Liu, Zhenhai Li, Chengxuan Ye, Hongfei Zhang, Hongwu Li, Hui Zheng, Yonggang State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial Equipment Department of Engineering Mechanics School of Mechanics and Aerospace Engineering Dalian University of Technology Dalian116024 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610200 China

A coupled axisymmetric peridynamics with a stabilized correspondence material model (CA-PD-SCMM) is proposed in this work to effectively simulate the ablation and ductile fracture behaviors of metals under high temperatures. To quantify the damage resulting from compression and shearing deformations, a strain energy density decomposition method is incorporated into the ductile damage model. Furthermore, a novel axisymmetric stabilization method based on peridynamics linearization theory is introduced to mitigate numerical oscillations arising from zero-energy modes in both thermal and mechanical scenarios. To capture the varying geometries and update the boundary conditions during ablation, a moving boundary model is developed based on temperature-associated criteria. To validate the capacity of the proposed CA-PD-SCMM, several representative numerical experiments are conducted. These examples not only affirm its ability to stabilize numerical oscillations in coupled axisymmetric thermoplastic problems but also demonstrate its capability for accurately simulating ablation and predicting crack propagation. © 2024, The Authors. All rights reserved.

关键词： Ductile fracture

MOLECULAR DYNAMICS STUDY on THERMAL CONDUCTIVITY of UNIRRADIATED and IRRADIATED SYMMETRICAL TILT GRAIN BOUNDARY 3C-SIC 29

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MOLECULAR DYNAMICS STUDY on THERMAL CONDUCTIVITY of UNIRRADI...

2022 29th International Conference on Nuclear Engineering, ICONE 2022

作者： Cai, Ziqi Shao, Zhuang Li, Yuanming Zhang, Qingmin Department of Nuclear Science and Technology School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610200 China Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi'an710049 China Shaanxi Engineering Research Center of Advanced Nuclear Energy Xi'an Jiaotong University Xi'an710049 China

ISBN: (纸本)9780791886366

The cubic silicon carbide (3C-SiC) has been considered as a candidate structural material for several types of advanced nuclear reactors. The effects of cascade collision on thermal conductivity in symmetrical tilt grain boundary (GB) were studied by Molecular dynamics (MD) simulations. The thermal conductivity of 3C-SiC at 5(210)[001] GB was calculated using non-equilibrium molecular dynamics (NEMD) methods. A relatively small simulation unit was used to analyze the effect of different energies of incident PKA (primary knock-on atoms) on the thermal conductivity of 3C-SiC and to compare the results with perfect structure GB system. Finally, the vibrational density of states (VDOS) of atoms in the GB region was calculated to analyze the phonon mismatch at the interface. Calculations show that cascade collisions generated by energetic atoms will result in a decrease in thermal conductivity of the 5(210) GB system, but the effect varies in different regions, with a sharp decrease in thermal conductivity and an increase in thermal resistance for the intracrystalline region, while the magnitude of change in either thermal resistance or thermal conductivity is not significant in the GB region. Irradiated model shows a higher GB energy compared to the unirradiated model. For all irradiated models, lattice defects have a significant effect on the thermal conductivity of the GB system, depending on the spatial structure of the *** results of the VDOS analysis suggest that an increase in the degree of atomic lattice mismatch near the interface is responsible for a further increase in the thermal resistance of the irradiated GB system. © 2022 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Grain boundaries

Corrosive Effect on Saturated Pool Boiling Heat Transfer Characteristics of Metallic Surfaces with Hierarchical Micro/Nano Structures

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SSRN 2023年

作者： Xu, Wei Tang, Longchang Zhao, Ningkang Ouyang, Kun Zeng, Chang Liu, Xiaojing He, Xiaoqiang College of Smart Energy Shanghai Jiao Tong University Shanghai200240 China Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

Surface modification is of critical interest to enhance boiling heat transfer in terms of heat transfer coefficient or critical heat flux (CHF), which is significantly affected by distinct surface morphology and wettability and it can improve the efficiency and safety of equipment. Furthermore, actual service environment may cause severe corrosion to the processed structured surfaces while its consequence on boiling heat transfer is still obscure. In this research, comprehensive researches are conducted to unravel corrosive effect on metallic samples made of stainless steel (SS) and Inconel materials with microstructures. Different constructions (i.e., microgroove, microcavity and micropillar array) and characteristic dimensions (~20, 50 μm) of microstructure, various duration time (up to 300 days) and pH values (~7.0 to 8.5) of corrosive environment are compared thoroughly. Conclusions can be drawn that not all microstructures can enhance pool boiling heat transfer characteristics, especially in terms of CHF values. More importantly, CHF value of SS microgroove sample firstly increases from 60.94 to 94.09 W·cm-2 in 50 days, then decreases to 47.77 W·cm-2 in 300 days, which can be attributed to competition result between formation of hierarchical micro/nano structure with enhancing wicking capability and chemistry condition with increasing contact angle. In addition, distinct bubble dynamics during pool boiling is also analyzed. The insights obtained from this article can be used to guide surface modification method and to reveal evolvement rule of engineered metallic surface in highly corrosive and harsh boiling heating transfer environment. © 2023, The Authors. All rights reserved.

关键词： Corrosive effects

Research on Optimization of Momentum Source Model to Supercritical Carbon Dioxide Flow in Wire Wrapped Rods Bundle

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SSRN 2023年

作者： Liu, Sichao Liu, Yu Yang, Xiaolei Li, Xiaochang Tian, Ruifeng College of Nuclear Science and Technology Harbin Engineering University Harbin150001 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu601213 China College of Aerospace and Civil Engineering Harbin Engineering University Harbin150001 China

Wrapped wire is widely used in new reactor core design. Simulation with traditional body fitted grid needs a large number of grids, which requires more computing resources. By optimizing the basic mathematical model of momentum source method, simulation of wire wrapped rod bundle with arbitrary wire shape can be carried out. By simulating the experimental data of 3 wire wrapped rod bundle, the model adaptability of momentum source method and mesh sensitivity analysis are carried out. Then optimized momentum source method and original momentum source method are compared based on simulation of supercritical carbon dioxide flow and heat transfer in wire wrapped rod bundle with different wire shapes. Through comparison with body fitted grid, the improvement of accuracy of optimized momentum source model can be proved. In conclusion, optimized momentum source method can greatly save the computational resources and calculated results is more accurate than original momentum source method. © 2023, The Authors. All rights reserved.

关键词： Wire

Optimization design of the reactor coolant pump flywheel comprised of multi-ring packing heavy metal alloy 9

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Optimization design of the reactor coolant pump flywheel com...

9th Global Conference on Materials science and Engineering, CMSE 2020

作者： Jiang, L. Wu, C.W. Shao, X.J. Zhang, Y. Yu, M.D. National Key Laboratory of Science and Technology on Reactor System Design Technology Nuclear Power Institute of China Chengdu610041 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian116024 China

To improve energy storage performance of the multi-ring RCP flywheel comprised of inner hub, tungsten alloy ring and outer retainer, optimization design process for the radial thicknesses of components and interference fit assembly is demonstrated. Radial thicknesses of these components and magnitude of interference fit are set as design parameters to construct parametric analysis model. design of experiments (DOE) technique is adopted to generate design matrix for sensitive analysis. Subsequently, radial basis function (RBF) approximation is employed to search for the optimal design considering structural integrity requirement. Finally, a proper range of the magnitude of interference fit is obtained which can not only prevent neither slippage nor separation between the inner hub and tungsten alloy ring but also ensure the safety of structural strength. In addition, it is found that to ensure a high moment of inertia and energy density, a reasonable large radial thickness of tungsten alloy ring and a reasonable small radial thickness of outer retainer are required. © Published under licence by IOP Publishing Ltd.

关键词： Heavy metals

In situ SR-CT Experimental Study on the Directional Sintering of High-Temperature Superconductor YBCO Materials in the Microwave Fields

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Acta Metallurgica Sinica(English Letters) 2022年第1期35卷 67-77页

作者： Liangyuan Wang Lei Shen Yongcun Li Yuanjie Wang Yu Xiao Xingyi Zhang Feng Xu Xiaofang Hu CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of ChinaAnhui230027China Key Laboratory of Mechanics on Disaster and Environment in Western China Attached to the Ministry of Education of China Lanzhou UniversityLanzhou730000China Shanxi Key Lab of Material Strength&Structural Impact College of Mechanical and Vehicle EngineeringTaiyuan University of TechnologyTaiyuan030024China

YBa_(2)Cu_(3)O_(7-x)(YBCO)is a kind of high-temperature superconducting material that has important application in information,energy,medical treatment,etc.,and the superconducting properties of YBCO are closely related to its internal *** this study,the microwave heating method was adopted to prepare the YBCO *** internal 3 D online evolution observation based on the synchrotron radiation computed tomography technology shows that there was directional grain growth phenomenon of YBCO during microwave sintering *** local regions with special microstructure,these particles grew to the same ***,the theoretical models of single and multiple particles in the microwave electromagnetic fields were *** on these theoretical models and finite element analysis,it shows that the YBCO particles can modulate the distribution of electromagnetic fields,resulting in the significantly higher electric field intensity at the particle junctions than other ***,there were very high electric field intensity and temperature gradients in the directions of particle *** factors were crucial in directional *** results will provide theoretical basis and technical guidance for the controllable preparation and performance optimization of the internal microstructure of superconducting materials in the preparation process.

关键词： Synchrotron radiation computed tomography Microwave sintering Microstructure In situ

Microstructure and mechanical properties of tib2/ al-si composites fabricated by electron beam rapid manufacture 21st

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Microstructure and mechanical properties of tib2/ al-si comp...

21st Chinese Materials Conference, CMC 2020

作者： Yang, Qingfeng Xia, Cunjuan Li, Xianfeng Wang, Haowei Liao, Nan Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China The State Key Laboratory of Metal Matrix Composites Shanghai Jiaotong University Shanghai200240 China

ISBN: (纸本)9783035717389

Bulky sample was fabricated by electron beam rapid manufacture (EBRM) technology, in which Ф1.6 mm wire of in-situ TiB2/Al-Si compositeswas selected as deposition metal, following byT6 heat treatment. The microstructure and mechanical properties of the bulky sample before and afterheat treatment were analyzed. Experimental results showed that the microstructure parallel to the weld was similar to that perpendicular to the weld. The microstructure of the as-deposited sample consisted of columnar and equiaxed grains, in which siliconwas distributed along the grain boundary and the grain size was about 30 μm. Besides, some TiB2 particles converged at the grain boundary. After T6 heat treatment, the average grain size of the sample *** average hardness of the sample was increased to 114.65 HV from 46.55 HV, an increase of 146%. The tensile strength of the sample increased to 326.66MPafrom 143.97 MPa, but the elongationdecreased compared with that of the as-deposited state. The tensile test showed that the mechanical properties of TiB2/Al-Si composites formed by electron beam rapid manufacture were isotropic before and after heat treatment. © 2021 Trans Tech Publications Ltd, Switzerland.

关键词： Electron beams

Insights into Dissolved Oxygen Dependent Crack Initiation Mechanism of 316ln Stainless Steel Fatigue Tested in High-Temperature Pressurized Water

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SSRN 2024年

作者： Qiao, Yufei Li, Hui Tan, Jibo Liu, Daoping Zhang, Ziyu Wu, Xinqiang Ke, Wei CAS Key Laboratory of Nuclear Materials and Safety Assessment Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China School of Materials Science and Engineering University of Science and Technology of China Hefei230026 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China China

The corrosion fatigue behavior of 316LN SS hollow specimen was investigated in high-temperature pressurized water at different dissolved oxygen (DO) concentrations ( © 2024, The Authors. All rights reserved.

关键词： Corrosion fatigue

Experimental Investigation of Droplet Transient Behavior During Reflood Cooling Process of Single-Rod Channel

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SSRN 2023年

作者： Chen, Mingjing Chen, Deqi Liu, Haiong Liu, Hanzhou Zhong, Lei Deng, Jian Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing University Ministry of Education Chongqing400044 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

The reflood process after a loss of coolant accident (LOCA) in a nuclear reactor involves complex two-phase flow with low pressure and flow rate, as well as boiling phase transition. Accurately predicting the transient behavior of liquid droplets during the dispersed flow stage is crucial for evaluating reactor accidents, including peak cladding temperature (PCT). However, existing prediction models for liquid droplets in dispersed flows are typically based on quasi steady-state annular flow models and do not account for transient behavior, such as the propulsion characteristics of the quench front during strong transient flooding processes, and the formation mechanism of large droplets. In this study, we present the results of a visualization experiment of reflood cooling in a single-rod channel to investigate the development mechanisms of droplet formation and fragmentation. We observe the evolution behavior of the vapor-liquid interface during the reflood process and quantitatively analyze the transient size distribution characteristics of the droplets. Based on these findings, the transient characteristics of the quench front propagation during reflood, Kelvin-Helmholtz (K-H) instability, hot wall ejection mechanisms for droplet formation, and aerodynamic and capillary breakup mechanisms for droplet breakage, as well as entrainment and evaporation of droplets under high-speed steam are considered. A prediction model for droplet transient behavior during single-rod channel reflood cooling is established, and the results are compared with experimental data. © 2023, The Authors. All rights reserved.

关键词： Cooling