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An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps

Chinese Journal of Mechanical Engineering 2020年第2期33卷 43-55页

作者： Jimin Xu Changhuan Li Xusheng Miao Cuiping Zhang Xiaoyang Yuan Institute of Tribology School of Mechanical EngineeringHefei University of TechnologyHefei 230009China Aerospace Propulsion Institute China Aerospace Science and Technology CorporationXi’an 710100China Science Technology on Combustion Internal Flow and Thermal‑structure LaboratoryNorthwestern Polytechnical UniversityXi’an 710012China Superconducting Materials Research Center Laboratory Northwest Institute for Non-ferrous Metal ResearchXi’an 710016China Key Laboratory of Education Ministry for Modern Design and Rotor‑Bearing System Xi’an Jiaotong UniversityXi’an 710049China

There is a consensus in the aerospace field that the development of reusable liquid rockets can effectively reduce the launch *** pursuit of a long service life and reutilization highly depends on the bearing ***,the rolling element bearings(REBs)used in the existing rocket turbopumps present obvious and increasing limitations due to their mechanical contacting *** REBs,high rotational speed and long service life are two performance indexes that mutually restrict each *** go beyond the DN value(the product of the bearing bore and rotational speed)limit of REBs,the major space powers have conducted substantial explorations on the use of new types of bearings to replace the *** review discusses,first,the crucial role of bearings in rocket turbopumps and the related structural improvements of ***,with the prospect of application to the next generation of reusable liquid rocket turbopumps,the bearing candidates investigated by major space powers are summarized *** promising alternatives to REBs include fluid-film,foil,and magnetic bearings,together with the novel superconducting compound bearings recently proposed by our *** more than ten years of relevant research on fluid-film and magnetic bearings are also *** review is meaningful for the development of long-life and highly reliable bearings to be used in future reusable rocket turbopumps.

关键词： Aerospace Reusable liquid rocket turbopumps Rolling element bearings Bearing candidates Review

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Fast Calculate Bistatic RCS Using Compressive Sensing and Characteristic Basis Function Method

Fast Calculate Bistatic RCS Using Compressive Sensing and Ch...

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International Conference on Microwave and Millimeter Wave technology Proceedings

作者： Chenlu Li Zhonggen Wang Zhenzhen Chen AnHui Province Key Laboratory of simulation and design for Electronic information system Hefei Normal University Hefei China Anhui University of Science and Technology Huainan China Hefei University Hefei China

ISBN: (纸本)9781665482271

In this paper, the sparse basis in Compressive Sensing (CS) is constructed by the characteristic basis functions (CBFs) when dealing with the bistatic scattering problems. The matrix consisting of primary and secondary CBFs are naturally sparse, thus it is regarded as the sparse transform matrix. Then it is used to construct a undetermined equation to solve the weighting coefficient. The surface induced current is recovered efficiently by the OMP algorithm. The results of the bistatic RCS calculation of a conductor target with a structure like a bullet by the proposed method are consistent with that of the MoM, the accuracy of CS-CBFs is demonstrated.

关键词： Microwave technology Microwave integrated circuits Millimeter wave technology Scattering Transforms Mathematical models Sparse matrices

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Flow and Leakage Characteristics in Sealing Chamber of a Variable Geometry Hypersonic Inlet

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Transactions of Nanjing University of Aeronautics and Astronautics 2022年第6期39卷 663-671页

作者： XIA Feng SUN Bo YU Jianyi YUE Lianjie GAO Yu DAI Chunliang College of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094P.R.China Beijing System Design Institute of Electro-mechanic Engineering Beijing 100190P.R.China State Key Laboratory of High-Temperature Gas Dynamics Beijing 100190P.R.China

When the variable geometry hypersonic inlet is sealed with ceramic wafers,the cavity flows inside the sealing chamber can be affected by the boundary layer near the side *** study the influence of the boundary layer thickness near the side wall on the flow and leakage characteristics in sealing chamber,the numerical calculation of the cavity flow in the sealing chamber under different inflow boundary layer thicknesses is carried *** results show that three-dimensional cavity flow structures are close to being asymmetric,and the entrance pressure of the leakage path can also be affected by asymmetry;with the increase of the thickness of the boundary layer,the pressure at the cavity floor and the seal entrance ***,the existing leakage prediction model is modified according to the distribution rule of the cavity floor and the flow properties in the leakage path.

关键词： variable geometry inlet ceramic wafer seal vortex structure leakage rate asymmetry three-dimensional cavity flow

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Preliminary evaluation of fecral-UN fuel rod performance 14

Preliminary evaluation of fecral-UN fuel rod performance

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14th International Nuclear Fuel Cycle Conference, GLOBAL 2019 and Light Water reactor Fuel Performance Conference, TOP FUEL 2019

作者： Gao, Shixin Duan, Zhengang Zhou, Yi Chen, Ping He, Liang Liu, Shichao Zhang, Kun Qiu, Xi Zhang, Ruiqian Science and Technology on Reactor System Design Technology Laboratory No.328 Section 1 Changshun Road Shuangliu County Chengdu610213 China Nuclear Power Institute of China No.328 Section 1 Changshun Road Shuangliu County Chengdu610213 China

After the accident at the Fukushima Daiichi nuclear power plant, many institutions around the world developed the development of accident-tolerant fuel (ATF). Many institutions in China have been conducting research and development on accident tolerant fuels. NPIC plays the most important role in the CNNC Accident Tolerant Fuel (ATF) program, which aims to develop advanced fuels and claddings that have improved performance under normal conditions, design basis accidents (DBA) and beyond design basis accidents (BDBA). Due to its excellent corrosion resistance, FeCrAl stainless steel has become one of the most important ATF cladding concepts. The FeCrAl concept provides the operator with some extra coping time to deal with accident conditions compared to traditional zirconium-based cladding. Uranium mononitride has been identified as an alternative fuel with higher uranium density and thermal conductivity when compared to UO2. In NPIC ATF campaign, FeCrAl is one of the advanced cladding concepts and UN is one of the advanced fuel candidates. NPIC has developed about 4m full-length thin-walled FeCrAl tubes with several varied chemical composition as fuel rod cladding. NPIC also prepared UN fuel pellets by sintering. This paper focuses on in-pile performance analysis of UN fuel rod with FeCrAl cladding, so as to make suggestions for future FeCrAl-UN fuel rod research, preparation and application. This paper uses FUPAC code to make analysis on fuel rod in-pile performance. The simulation uses the most recently known material properties. Some analyses of FeCrAl-UN fuel rod performance at steady state conditions are performed. And the results show that FeCrAl-UN fuel rod has good performance in aspects such as fuel temperature, fission gas release, fuel rod internal pressure, etc. Finally, future research and development work are discussed. Copyright © GLOBAL 2019 - International Nuclear Fuel Cycle Conference and TOP FUEL 2019 - Light Water reactor Fuel Performance Confere

关键词： Ternary alloys

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Data-driven modeling fast-slow coupling delayed dynamics using noisy data and sparse enhancement

Data-driven modeling fast-slow coupling delayed dynamics usi...

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International Conference on Industrial Artificial Intelligence (IAI)

作者： Huifang Tang Yuqiang Wu Yingming Dong Cheng Cheng Xiuting Li College of Science Huazhong Agricultural University Wuhan China School of Artificial Intelligence and Automation Huazhong University of Science and Techonology Wuhan China Yunnan Key Laboratory of Mechatronics Applied Technology Yunnan Mechanical Research and Design Institute of Machinery Research Institute Group Yunnan China Autonomous Intelligent Unmanned System Engineering Research Center Ministry of Education of China Huazhong University of Science and Technology Wuhan China

In this work, we focus on fast-slow delayed dynamical systems, which are usually described by coupled delayed differential equations with two-time scales. The purpose of this article is to propose a data-driven discovery method to identify the fast-slow delayed differential equations from noisy measurements. The proposed method blends delay dictionary-based sparse identification of nonlinear dynamics (SINDy) framework and a fixed interval sampling strategy. Specifically, we leverage the SINDy methodology to describe the fast-slow delayed differential equations by a few active terms of a large dictionary containing the delay terms and many candidate nonlinear basis functions. To identify the active terms and the corresponding coefficients, a sequential thresholded re-weighted ℓ 2 least squares algorithm is used to solve the resulting sparse regression problem to enhance the sparsity. Once a sparse model with fixed delay is selected, the proposed method further estimates the delayed time by calculating the reconstruction error from the sparse model until the one that makes the reconstruction error minimum. We verify the effectiveness of the proposed method with several classical fast-slow coupling delayed systems. The experimental results show that the proposed method can well automate the fast-slow delayed differential equations from noisy data and the delayed terms also can be detected accurately.

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Stacking, Strain-Engineering Induced Altermagnetism, Multipiezo Effect, and Topological State in Two-Dimensional Materials

arXiv

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arXiv 2025年

作者： Xun, Wei Liu, Xin Zhang, Youdong Wu, Yin-Zhong Li, Ping Jiangsu Engineering Research Center for Design and Application of Intelligent Detection Equipment School of Electronic Engineering Jiangsu Vocational College of Electronics and Information Huaian223003 China School of Physical Science and Technology Suzhou University of Science and Technology Suzhou215009 China State Key Laboratory for Mechanical Behavior of Materials Center for Spintronics and Quantum System School of Materials Science and Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory for Surface Physics Department of Physics Fudan University Shanghai200433 China State Key Laboratory of Silicon and Advanced Semiconductor Materials Zhejiang University Hangzhou310027 China

Altermagnetism, as a newly identified form of unconventional antiferromagnetism, enables the removal of spin degeneracy in the absence of net magnetization that provides a platform for the low power consumption and ultra-fast device applications. However, the rare attention has been paid to the relationship between stacking, strain and altermagnet, multipiezo effect and topological state. Here, we propose a mechanism to realize the altermagnet, multipiezo effect, and topological state in two-dimensional materials by the stacking and strain engineering. Based on the analysis of symmetry, we find that the spin splitting feature related to the Ut, PTt, MzUt, or MzPTt symmetries in altermagnet multilayers. In addition, we find that the stacking engineering can effectively realize the transform from antiferromagnetism to altermagnetism and semiconductor to metal for the Jauns bilayer V2SeTeO. More interestingly, the strain not only induces an intriguing multipiezo effect, encompassing the piezovalley, piezomagnetism and piezoelectric, but also achieves the abundant topological phase. Our findings offer a generalized direction for manipulating the spin splitting, valley polarization, and topological states, promoting practical application of valleytronic and spintronic devices based on two-dimensional altermagnets. © 2025, CC BY.

关键词： Antiferromagnetism

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Optimal Linear Crossover for Mitigating Negative Transfer in Evolutionary Multitasking

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IEEE Transactions on Evolutionary Computation 2024年

作者： Liu, Zhaobo Yuan, Jianhua Zhang, Haili Zeng, Tao Zhu, Zexuan Shenzhen University Institute for Advanced Study Shenzhen518060 China Shenzhen University College of Computer Science and Software Engineering Shenzhen518060 China Shenzhen Polytechnic University School of Undergraduate Education Shenzhen518055 China Shenzhen University National Engineering Laboratory for Big Data System Computing Technology Shenzhen518060 China Shenzhen University Shenzhen City Key Laboratory of Embedded System Design Shenzhen518060 China Chongqing University Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education of China Chongqing400044 China

Evolutionary multitasking algorithms use information exchange among individuals in a population to solve multiple optimization problems simultaneously. Negative transfer is a critical factor that affects the performance of evolutionary multitasking algorithms. In this study, we propose an innovative approach to mitigate negative transfer in evolutionary multitasking algorithms. The proposed approach is grounded in rigorous theoretical analysis, which provides valuable theoretical insights into the design of an optimal linear crossover operator for mitigating negative transfer. By identifying interpretable conditions, we establish a solid theoretical foundation to prevent negative transfer in diverse scenarios. Building upon these findings, we theoretically derive a closed-form expression for the optimal crossover operator and propose practical design methods based on approximations. Furthermore, we integrate the proposed optimal crossover operator into a fundamental evolutionary multitasking algorithm framework. The resultant algorithm is comparable or superior to other state-of-the-art methods. Empirical validation through comprehensive experiments confirms the effectiveness of our theoretical findings. © 1997-2012 IEEE.

关键词： Optimization algorithms

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PRELIMINARY NEUTRONIC/THERMAL-HYDRAULIC AND SAFETY ASSESSMENT OF PRESSURIZED WATER reactor LOADED WITH FULLY CERAMIC MICROENCAPSULATED FUEL

PRELIMINARY NEUTRONIC/THERMAL-HYDRAULIC AND SAFETY ASSESSMEN...

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2020 International Topical Meeting on Advances in Thermal Hydraulics, ATH 2020

作者： Wu, Di Gui, Minyang Zhang, Dalin Wang, Chenglong Wu, Yingwei Su, G.H. Qiu, Suizheng Tian, Wenxi Yang, Hongfa Peng, Jingyang Shanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Nuclear and Radiation Safety Center Ministry of Ecology and Environment of the People's Republic of China Beijing100082 China

ISBN: (纸本)9780894487774

As one of the accident tolerant fuels (ATFs), fully ceramic microencapsulated (FCM) fuel shows superior safety performance in accidents, which has the characteristics of high melting point, excellent heat transfer ability and strong nuclear proliferation resistance. Based on the neutronic analysis of Chinese advanced three loop pressurized water reactor (PWR), the assemblies and cores of FCM-SiC and UO2-Zr were designed, power distributions and cycle lengths were obtained, and the power was adjusted to ensure the annual refueling requirements. By using system analysis code, station blackout (SBO) accident in FCM-SiC and UO2-Zr was analyzed, where the steam-driven auxiliary feedwater (AFW) in secondary loop failed to be supplied in time. Assuming that the AFW system couldn't be put into operation immediately after accident, the critical time could be calculated, that is to say, fuel centerline temperature (FCT) and peak cladding temperature (PCT) wouldn't exceed corresponding limits during accident once the AFW was provided within the critical time. It is found that the critical time of FCM-SiC is 9000s and higher than that of UO2-Zr (7000s), which shows the advantages of ATFs. This work could provide reference for the optimized design of the reactor safety system in the future. © ATH 2020 - International Topical Meeting on Advances in Thermal *** rights reserved.

关键词： Silicon carbide

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Large deformation and wrinkling analyses of bimodular structures and membranes based on a peridynamic computational framework

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Acta Mechanica Sinica 2019年第6期35卷 1226-1240页

作者： H.Li Y.G.Zheng Y.X.Zhang H.F.Ye H.W.Zhang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610200China International Research Center for Computational Mechanics State Key Laboratory of Structural Analysis for Industrial EquipmentDepartment of Engineering MechanicsFaculty of Vehicle Engineering and MechanicsDalian University of TechnologyDalian 116024China

In this paper,the quasi-static large deformation,wrinkling and fracture behaviors of bimodular structures and membranes are studied with an implicit bond-based peridynamic computational ***,the constant and tangential stiffness matrices of the implicit peridynamic formulations for the nonlinear problems are derived,*** former is con structed from the linearization of the bond strain on the basis of the geometric approximation while the latter is established according to the linearization of the pairwise force by using first-order Taylor’s ***,a bimodular material model in peridynamics is developed,in which the tensile or compressive behavior of the material at each point is conveniently described by the tensile or compressive states of the bonds in its ***,the bimodular material model is extended to deal with the wrinkling and fracture problems of membranes by setting the compressive micro-modulus to be *** addition,the incremental-iterative algorithm is adopted to obtain the convergent solutions of the nonlinear ***,several representative numerical examples are presented and the results demonstrate the accuracy and efficiency of the proposed method for the large deformation,wrinkling and fracture analyses of bimodular structures and membranes.

关键词： Bimodular structures Wrinkling membranes Fracture problems Peridynamics Implicit numerical algorithm

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Nonstoichiometric Protic Ionic Liquids for Efficient Carbon Dioxide Capture

SSRN

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SSRN 2023年

作者： Wang, Litian Chen, Jie Li, Dan Li, Cuiping Qian, Lirong Xiong, Yang Xie, Zhiyong Wang, Shuai Zhou, Tongyao Gai, Baojia Wang, Yinuo Tianjin Key Laboratory of Film Electronic and Communication Devices School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Tianjin Bohua Yongli Chemical Industry CO. Ltd Tianjin30045 China

Protic ionic liquids (PILs) have emerged as promising solvents for CO2 capture, offering great potential for the development of efficient CO2 absorbents. Understanding the relationship between the PILs’ structures and CO2absorption mechanisms is instructive for advancing their applicability. Herein, an innovative strategy for CO2 capture using nonstoichiometric PILs was demonstrated for the first time. These nonstoichiometric PILs composed of imidazole (Im) as a Brønsted acid and 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) as a Brønsted base with various ratios. They exhibited both low viscosities and remarkable CO2 loading capacities, reaching up to 0.194 g CO2 /g IL and 1.42 mol CO2 /mol IL at 0.1 atm and 40 °C. The distribution of neutral and ionic species in these nonstoichiometric PILs was determined using density functional theory (DFT) calculations and nuclear magnetic (NMR) spectroscopy analysis. Correlations between the mole ratio of Brønsted acid and base and the viscosities, conductivities, and CO2 absorption properties were observed. The mechanism of CO2 absorption was proposed from the spectral results and DFT calculations. The superior CO2 loading ability of these PILs can be attributed to the formation of the zwitterionic carbamic complexes through interactions between CO2 and the N atom in DBU. Additionally, the presentence of Im significantly avoided the dramatic increase in the viscosity of the absorbents during CO2 absorption. It is believed that the new insights into the CO2 mechanism will facilitate the rational design of PILs for CO2 capture in the future. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

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