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A Novel Asymmetric Check Microvalve for Suppressing Flow Boiling Instability in Microchannels

Journal of thermal Science 2024年第6期33卷 2336-2347页

作者： ZHOU Fan ZHAO Yang YIN Ershuai HU Dinghua LI Qiang MIIT Key Laboratory of Thermal Control of Electronic Equipment School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China

Flow boiling in microchannels has attracted wide attention due to its excellent heat transfer capability,but flow boiling instability is a huge challenge limiting its *** can lead to a series of problems,such as uneven flow distribution,temperature and pressure drop *** work proposes a novel asymmetric check microvalve(ACMV)structure,exhibiting high ratio of resistance between the reverse and forward *** results show the reverse pressure drop of the ACMV structure is 2.06 times that of the forward pressure drop,and the forward flow resistance of the ACMV structure is 16%smaller than that of the conventional inlet *** addition,bubble dynamics of an isolated bubble in the generated channel under dual outlet condition was numerically *** is found that the bubble grows symmetrically in the rectangular channel upstream and *** distance of bubble movement downstream in the microchannel with ACMV is three times that of the microchannel with inlet *** microchannel with ACMV can suppress the backflow of isolated bubble better than microchannel with inlet ***,the growth of the bubble downstream extends the effective evaporation domain,which contributes to the enhanced bubble growth *** ACMV is expected to be a potential replacement for the conventional inlet restrictor,which provides a novel and efficient solution for future heat dissipation from high power devices.

关键词： flow boiling instability topology optimization microchannel bubble dynamics

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Impulsive thrust strategy for orbital pursuit-evasion games based on impulse-like constraint

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Chinese Journal of Aeronautics 2025年第1期38卷 520-536页

作者： Hongbo WANG Yao ZHANG Hao LIU Kunpeng ZHANG School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Space Intelligent Control Beijing Institute of Control EngineeringBeijing 100094China

This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust *** strategy seeks to enhance the interpretability of impulsive thrust strategy by integrating it within the framework of differential game in traditional continuous ***,this paper introduces an impulse-like constraint,with periodical changes in thrust amplitude,to characterize the impulsive thrust ***,the game with the impulse-like constraint is converted into the two-point boundary value problem,which is solved by the combined shooting and deep learning method proposed in this *** learning and numerical optimization are employed to obtain the guesses for unknown terminal adjoint variables and the game terminal ***,the accurate values are solved by the shooting method to yield the optimal continuous thrust strategy with the impulse-like ***,the shooting method is iteratively employed at each impulse decision moment to derive the impulsive thrust strategy guided by the optimal continuous thrust *** examples demonstrate the convergence of the combined shooting and deep learning method,even if the strongly nonlinear impulse-like constraint is *** effect of the impulsive thrust strategy guided by the optimal continuous thrust strategy is also discussed.

关键词： Orbital pursuit-evasion game Differential game Impulsive thrust Deep learning Shooting method

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Combustion characteristics of millimeter-sized aluminum particles in fluidized bed under various O_(2)/CO_(2)/H_(2)O atmospheres Author links open overlay panel

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Particuology 2024年第8期91卷 315-322页

作者： Jialing Zhou Rui Zhang Dong Liu Key Laboratory of Thermal Control of Electronic Equipment Ministry of Industry and Information TechnologyNanjing210094China Advanced Combustion Laboratory School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China

Aluminum is an attractive alternative fuel,but it burns very inefficiently due to the formation of a dense Al_(2)O_(3)layer which prevents O_(2)from diffusion to the surface of Al *** previous experiments,the combustion of millimeter-sized Al(mAl)particles in the fluidized bed has achieved a substantial increase in the combustion efficiency,but further improvements are still *** this study,the effects of reaction atmosphere on the fluidized combustion of mAl particles were *** experiments with different O_(2)/H_(2)O/CO_(2)concentrations were *** experimental results indicate that the combustion efficiency of mAl particles in fluidized bed increases as the mole fraction of O_(2),H_(2)O or CO_(2)increases,and the highest combustion efficiency can reach 38.7%.After the analysis of the oxide film on the surface of aluminum particles,it was found that it is easier to generate the unstableθ-Al_(2)O_(3)under CO_(2)atmosphere,and it is easier to generate the unstableγ-Al_(2)O_(3)andθ-Al_(2)O_(3)under H_(2)O *** unstable Al_(2)O_(3)film is more likely to be abraded in the fluidized bed,which leads to the effective improvement of the combustion efficiency.

关键词： Al combustion Fluidized bed Atmosphere Combustion efficiency

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thermal design and flight validation of the chang'e-4 relay satellite 2

Thermal design and flight validation of the chang'e-4 relay ...

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2023 2nd International Conference on Mechanical, Aerospace technology and Materials Application, MATMA 2023

作者： Ren, Hongyan Yang, Changpeng Sun, Tengfei Huang, Xing Beijing Key Laboratory of Space Thermal Control Technology Beijing Institute of Spacecraft System Engineering Beijing100094 China

The Chang'e-4 relay satellite operates in the HALO orbit at the Earth-Moon Lagrange L2 point, which can provide relay communication to the lander and the rover operating on the lunar far side to maintain their contacts with the earth and is a key link of the Chang'e-4 exploration mission. Unlike most LEO (Low Earth Orbit) satellites, the outer space environment of the Chang'e-4 relay satellite is much harsher. The Chang'e-4 relay satellite must suffer from a torrid environment that faces direct sunlight or direct exposure to 4K deep cold space in a shadow zone which may last longer than 6 hours. The Chang'e-4 relay satellite must ensure the operation and temperature control of instruments and equipment during the shadow zone with a limited battery level. This proposes high demands on the TCD (thermal control Design). The entire satellite resources were reasonably used for integrated TCD with limited battery level and limited weight. According to the working mode of the Chang'e-4 relay satellite and its torrid environment, its TCD was completed successfully, and on-orbit test data conformed to the expected results and theoretical calculation. TCD of the Chang'e-4 relay satellite has worked normally since the day that the Chang'e-4 relay satellite was launched into space. © Published under licence by IOP Publishing Ltd.

关键词： Earth (planet)

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Ground-based investigations on phase-moving phenomenon with space sublimation cooling for lunar exploration missions

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Chinese Journal of Aeronautics 2022年第8期35卷 65-74页

作者： Enhui LI Yunze LI Jixiang WANG Man YUAN Jingyan XIE Yuehang SUN Lizhu YANG Xianwen NING School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Beijing Key Laboratory of Space Thermal Control Technology China Academy of Space TechnologyBeijing 100094China

The lunar surface is a typical vacuum environment,and its harsh heat rejection conditions bring great challenges to the thermal control technology of the exploration *** addition to the radiator,the sublimator is recommended as one of the promising options for heat *** sublimator makes use of water to freeze and sublimate in a porous medium,rejecting heat to the vacuum *** complex heat and mass transfer process involves many physical phenomena such as the freezing and sublimation phase change of water in the porous medium and the movement of the phase-change *** this paper,the visualized ground-based experimental approaches of space sublimation cooling were presented to reveal the moving law of threephase point and the growth phenomenon of ice-peak and icicle in microchannels under vacuum *** visualized experiments and results prove that the freezing ice is divided into the porous ice-peak and the transparent *** the sublimation progresses,the phase-change interface moves downward steadily,the length of the ice-peak increases,but the icicle *** visualized experiments of space sublimation cooling in the capillary have guiding significance to reveal the sublimation cooling mechanism of water in the sublimator for lunar exploration missions.

关键词： Lunar vacuum environment Phase-change flow space sublimation cooling Unsteady phase-moving phenomenon Visualized ground-based experimental approaches

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Autonomous Recommendation of Fault Detection Algorithms for spacecraft

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 273-275页

作者： Wenbo Li Baoling Ning the National Key Laboratory of Science and Technology on Space Intelligent Control Beijing Institute of Control EngineeringBeijing 100094China the School of Data Science and Technology Heilongjiang UniversityHarbin 150001China

Dear Editor, This letter deals with the problem of algorithm recommendation for online fault detection of spacecraft. By transforming the time series data into distributions and introducing a distribution-aware measure, a principal method is designed for quantifying the detectabilities of fault detection algorithms over special datasets.

关键词： fault introducing letter

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Fault diagnosis method of link control system for gravitational wave detection

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Journal of Systems Engineering and Electronics 2024年第4期35卷 922-931页

作者： GAO Ai XU Shengnan ZHAO Zichen SHANG Haibin XU Rui School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of EducationBeijing 100081China

To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is *** from the traditional fault diagnosis optimization algorithms,the fault intelligent learning method pro-posed in this paper is able to quickly identify the faults of inter-satellite link control system despite the existence of strong cou-pling *** constructing a two-layer learning network,the method enables efficient joint diagnosis of fault areas and fault *** simulation results show that the average identification time of the system fault area and fault parameters is 0.27 s,and the fault diagnosis efficiency is improved by 99.8%compared with the traditional algorithm.

关键词： large scale multi-satellite formation gravitational wave detection laser link monitoring fault diagnosis deep learning

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Design of a widely adjustable electrochromic device based on the reversible metal electrodeposition of Ag nanocylinders

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Nano Research 2023年第1期16卷 1421-1429页

作者： Jiangrong Zhou Yuge Han MIIT Key Laboratory of Thermal Control of Electronic Equipment School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China

Structural colors resulting from nanostructured metallic surfaces hold a series of advantages compared to conventional chemical pigments and dyes,such as enhanced durability,tunability,scalability,and low consumption,making them particularly promising for preparing color-tunable ***,once these structures are fabricated,they are almost all passive devices with static nanostructures and fixed optical properties,limiting their potential ***,by using a specially designed array of ordered SiO2 nanoholes as a deposition template in conjunction with the traditional reversible metal electrodeposition device(RMED),we propose a tunable reflective surface where the color of the surface can be changed as a function of the thickness of the deposited Ag nanoparticles(AgNPs).Simplified manufacturability and a large range of color tunability are achieved over previous reports by utilizing the SiO2 nanohole template,which allows the direct deposition of AgNPs while forming an array structure of Ag ***,a further thematic analysis of the physical mechanism in the proposed structure is *** results show that the structural colors induced by the longitudinal localized surface plasmon resonance(LSPR)mode can be dynamically tuned from brown to purple via increasing the deposition ***,in combination with SiO2 nanohole templates of varying parameters,a full gamut of colors spanning the entire visible spectrum is achieved,revealing the feasibility of utilizing the properties of the LSPR mode for satisfying various color *** believe that this LSPRbased multicolor RMED design will contribute to the development of full color information displays and light-modulating devices.

关键词： structural color dynamic color tunability nanocylinder plasmonic nanostructures

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Optimal crater landmark selection based on optical navigation performance factors for planetary landing

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Chinese Journal of Aeronautics 2023年第3期36卷 254-270页

作者： Yi XIU Shengying ZHU Rui XU Maodeng LI School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of EducationBeijing 100081China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100091China

Planetary craters are natural navigation landmarks that widely exist and are easily *** navigation based on crater landmarks has become an important autonomous navigation method for planetary *** to the increase in observed crater landmarks and the limitation of onboard computation,the selection of good crater landmarks has gradually become a research hotspot in the field of landmark-based optical *** paper designs a fast crater landmark selection method,which not only considers the configuration observability of crater subsets but also focuses on the influence on navigation performance arising from the measurement uncertainty and the matching confidence of craters,which is different from other landmark selection *** factor of measurement uncertainty,which is anisotropic,correlated and nonidentically distributed,is quantified and integrated into selection based on crater pairing detection and localization error *** addition,the concept of the crater matching confidence factor is introduced,which reflects the possibility of 2D projection measurements corresponding to 3D *** with the configuration observability factor,the crater landmark selection indicator is ***,the effectiveness of the proposed method is verified by Monte Carlo simulations.

关键词： Crater-based optical navigation Crater landmark selection Crater matching Measurement uncertainty Planetary landing

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Unveiling the Investigation and Comfort Research in Various Scenarios of Mask Protection Equipment against Respiratory Transmission

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American Journal of Biochemistry and Biotechnology 2024年第1期20卷 7-15页

作者： Zhang, Xin Hebei Key Laboratory of Man-Machine Environment Thermal Control Technology and Equipment Hebei China Advanced Research Center of Thermal and New Energy Technologies Hebei Vocational University of Technology and Engineering Hebei China

Personal Protective Equipment (PPE) is essential to protect medical staff (HCW) from highly infectious diseases such as COVID-19 and masks are indeed important functional small effective defensive equipment in safeguarding the public from infection. However, the thermal comfort, fit, and difficulty breathing when wearing a mask can affect its use and improve filtration efficiency. In addition, there is a lack of available research on thermal comfort, fit, and respiration of masks under actual wearing conditions. To this end, a questionnaire survey and thermal comfort evaluation were used to investigate the thermal comfort and breathing difficulties of 75 volunteers wearing masks in Beijing, Tianjin, and Hebei. The results show that the main types of masks in various scenarios are medical masks. Except for the outdoors, the proportion of people who feel basic comfort and fit is the highest in these four areas. About a quarter of people experienced an average of 50-60 and 20-30 min of breathing difficulties in winter and summer, respectively. This study provides a systematic analysis and useful data for mask design and the development of human public health. © 2024 Xin Zhang.

关键词： Diseases

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