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Effect of cross-flow direction of coolant on film cooling effectiveness with one inlet and double outlet hole injection

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Propulsion and Power Research 2012年第1期1卷 71-77页

作者： Guangchao Lin Chaolin Wu Wei Zhang zhihai kou Dawei Peng Liaoning Key Laboratory of Advanced Technology for Aeronautical Propulsion System Aeroengine and Energy Engineering CollegeShenyang Aerospace UniversityShenyangLiaoning 110136China

In order to study the effect of cross-flow directions of an internal coolant on film cooling performance,the discharge coefficients and film cooling effectiveness with one inlet and double outlet hole injections were *** numerical results show that two different cross-flow directions of the coolant cause the same decrease in the discharge coefficients as that in the case of supplying coolant by a *** different proportion of the mass flow out of the two outlets of the film hole results in different values of the film cooling effectiveness for three different cases of coolant *** film cooling effectiveness is the highest for the case of supplying coolant by the *** a lower blowing ratio of 1.0,the film cooling effectiveness with coolant injection from the right entrance of the passage is higher than that from the left entrance of the *** a higher blowing ratio of 2.0,the opposite result is found.

关键词： Aerospace propulsion system Turbine blade Film cooling Cross-flow Numerical simulation

Friction Characteristics Between Marine Clay and Construction Materials

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Journal of Ocean University of China 2024年第2期23卷 427-437页

作者： kou Hailei HUANG Jiaming CHENG Yang College of Engineering Ocean University of ChinaQingdao 266100China Fourth Division Organization Department of the CPC Qingdao Municipal CommitteeQingdao 266100China

Structure-soil interface friction characteristics is of importance to investigate the interaction between engineering structures and soils,especially for offshore *** interface friction behavior between marine clay and structural materials with different roughness was studied in this paper by using 3D optical scanning tests,a modified direct shear device and numerical *** between the surface roughness of structures,water content and interface friction angle were presented by model *** increase of water contents decreased the interface friction *** interfaces with different roughness,the interface friction angles will be smaller than that of the soil when the water content exceeds a certain *** roughness of the interface and the water content of the soil are mutually coupled to influence the coefficient of friction(COF).This paper proposed a Finite Element Method(FEM)to simulate the interface direct shear tests of structures with different *** surface models with different roughness are established based on the structure data obtained by 3D *** Coupled Eulerian-Lagrangian(CEL)approach was employed to analyse soils sheared by irregular *** interface behavior for interfaces with different roughness under cyclic shear stresses was analyzed by FEM.

关键词： marine clay construction material interface friction behavior surface roughness Finite Element Method

A modified smoothed particle hydrodynamics method considering residual stress for simulating failure and its application in layered rock mass

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Journal of Mountain Science 2024年第6期21卷 2091-2112页

作者： XIA Chengzhi SHI Zhenming kou Huanjia Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating *** improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods(i.e.,the discrete element method).Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and *** fracture markψwas introduced to improve the kernel function after tensile damage,and the calculation of residual stress after the damage was derived after shear *** simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence,even fracture and *** results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock *** residual stress of brittle tock is correctly captured by the improved SPH *** improved SPH method that considers residual strength shows an approximately 13%improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength,as validated against analytical *** infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses.

关键词： Smoothed particle hydrodynamics Cracking strategy Residual stress Layered rock Crack propagation

Estimating the production of dark photons withηdecay in high-energy collisions

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Chinese Physics C 2024年第10期48卷 150-156页

作者： Wei kou Xurong Chen Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Southern Center for Nuclear Science Theory Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

We propose searching for dark photon signals in the decay channel of η mesons,specifically through the leptonic decay(A'→e^(+)e^(-)(μ^(+)μ^(-)))observable in photon-photon interactions during ultra-peripheral heavy-ion *** estimate the total cross-section for dark photon production in ultra-peripheral PbPb collisions at current and future hadron *** findings support the potential for detecting dark photon signals at the LHC,HighLuminosity LHC,High-Energy LHC,and Future Circular Collider.

关键词： dark photon ηdecay ultra-peripheral collision lead-lead collision

Spatial Heterogeneity of Embedded Water Consumption from the Perspective of Virtual Water Surplus and Deficit in the Yellow River Basin,China

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Chinese Geographical Science 2024年第2期34卷 311-326页

作者： MA Weijing LI Xiangjie kou Jingwen LI Chengyi College of Earth and Environmental Sciences Lanzhou UniversityLanzhou 730000China State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China School of Economics and Management Ningxia UniversityYinchuan 750021China

Virtual water trade(VWT)provides a new perspective for alleviating water crisis and has thus attracted widespread ***,the heterogeneity of virtual water trade inside and outside the river basin and its influencing factors remains further *** this study,for better investigating the pattern and heterogeneity of virtual water trade inside and outside provincial regions along the Yellow River Basin in 2015 using the input-output model(MRIO),we proposed two new concepts,i.e.,virtual water surplus and virtual water deficit,and then used the Logarithmic Mean Divisia Index(LMDI)model to identify the inherent mechanism of the imbalance of virtual water trade between provincial regions along the Yellow River Basin and the other four regions in *** results show that:1)in provincial regions along the Yellow River Basin,the less developed the economy was,the larger the contribution of the agricultural sector in virtual water trade,while the smaller the contribution of the industrial sector.2)Due to the large output of agricultural products,the upstream and midstream provincial regions of the Yellow River Basin had a virtual water surplus,with a net outflow of virtual water of 2.7×10^(8) m^(3) and 0.9×10^(8) m^(3),respectively.3)provincial regions along the Yellow River Basin were in a virtual water deficit with the rest of China,and the decisive factor was the active degree of trade with the *** study would be beneficial to illuminate the trade-related water use issues in provincial regions along the Yellow River Basin,which has farreaching practical signific-ance for alleviating water scarcity.

关键词： virtual water trade(VWT) input-output model(MRIO) virtual water surplus virtual water deficit Yellow River Basin,China

Highly Flexible Graphene-Film-Based Rectenna for Wireless Energy Harvesting

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Energy & Environmental Materials 2024年第2期7卷 320-325页

作者： Jingwei Zhang Yuchao Wang Rongguo Song Zongkui kou Daping He Hubei Engineering Research Center of RF-Microwave Technology and Application School of ScienceWuhan University of TechnologyWuhan 430070China Sanya Science and Education Innovation Park of Wuhan University of Technology Sanya 572000China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Herein,we report the design,fabrication,and performance of two wireless energy harvesting devices based on highly flexible graphene macroscopic films(FGMFs).We first demonstrate that benefiting from the high conductivity of up to 1×10^(6)S m^(-1)and good resistive stability of FGMFs even under extensive bending,the FGMFs-based rectifying circuit(GRC)exhibits good flexibility and RF-to-DC efficiency of 53%at 2.1 ***,we further expand the application of FGMFs to a flexible wideband monopole rectenna and a 2.45 GHz wearable rectenna for harvesting wireless *** wideband rectenna at various bending conditions produces a maximum conversion efficiency of 52%,46%,and 44%at the 5th Generation(5G)2.1 GHz,Industrial Long-Term Evolution(LTE)2.3 GHz,and Scientific Medical(ISM)2.45 GHz,respectively.A 2.45 GHz GRC is optimized and integrated with an AMC-backed wearable *** proposed 2.45 GHz wearable rectenna shows a maximum conversion efficiency of 55.7%.All the results indicate that the highly flexible graphene-film-based rectennas have great potential as a wireless power supplier for smart Internet of Things(loT)applications.

关键词： flexible rectennas highly flexible graphene-based films wireless energy harvesting

Heterogeneous data-driven aerodynamic modeling based on physical feature embedding

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Chinese Journal of Aeronautics 2024年第3期37卷 1-6页

作者： Weiwei ZHANG Xuhao PENG Jiaqing kou Xu WANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Institute of Aerodynamics RWTH Aachen UniversityAachen 52062Germany

Aerodynamic surrogate modeling mostly relies only on integrated loads data obtained from simulation or experiment,while neglecting and wasting the valuable distributed physical information on the *** make full use of both integrated and distributed loads,a modeling paradigm,called the heterogeneous data-driven aerodynamic modeling,is *** essential concept is to incorporate the physical information of distributed loads as additional constraints within the end-to-end aerodynamic *** heterogenous data,a novel and easily applicable physical feature embedding modeling framework is *** framework extracts lowdimensional physical features from pressure distribution and then effectively enhances the modeling of the integrated loads via feature *** proposed framework can be coupled with multiple feature extraction methods,and the well-performed generalization capabilities over different airfoils are verified through a transonic *** with traditional direct modeling,the proposed framework can reduce testing errors by almost 50%.Given the same prediction accuracy,it can save more than half of the training ***,the visualization analysis has revealed a significant correlation between the discovered low-dimensional physical features and the heterogeneous aerodynamic loads,which shows the interpretability and credibility of the superior performance offered by the proposed deep learning framework.

关键词： Transonic flow Data-driven modeling Feature embedding Heterogenous data Feature visualization

An air combat maneuver pattern extraction based on time series segmentation and clustering analysis

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Defence Technology（防务技术） 2024年第6期36卷 149-162页

作者： Zhifei Xi Yingxin kou Zhanwu Li Yue Lv You Li Air Force Engineering University No.1 Baling RoadBaqiao DistrictXi'anShaanxi ProvinceChina

Target maneuver recognition is a prerequisite for air combat situation awareness,trajectory prediction,threat assessment and maneuver *** get rid of the dependence of the current target maneuver recognition method on empirical criteria and sample data,and automatically and adaptively complete the task of extracting the target maneuver pattern,in this paper,an air combat maneuver pattern extraction based on time series segmentation and clustering analysis is proposed by combining autoencoder,G-G clustering algorithm and the selective ensemble clustering analysis ***,the autoencoder is used to extract key features of maneuvering trajectory to remove the impacts of redundant variables and reduce the data dimension;Then,taking the time information into account,the segmentation of Maneuver characteristic time series is realized with the improved FSTS-AEGG algorithm,and a large number of maneuver primitives are extracted;Finally,the maneuver primitives are grouped into some categories by using the selective ensemble multiple time series clustering algorithm,which can prove that each class represents a maneuver *** maneuver pattern extraction method is applied to small scale air combat trajectory and can recognize and correctly partition at least 71.3%of maneuver actions,indicating that the method is effective and satisfies the requirements for engineering *** addition,this method can provide data support for various target maneuvering recognition methods proposed in the literature,greatly reduce the workload and improve the recognition accuracy.

关键词： Maneuver pattern extraction Data mining Fuzzy segmentation Selective ensemble clustering

Model Parameters Identification and Backstepping Control of Lower Limb Exoskeleton Based on Enhanced Whale Algorithm

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 100-114页

作者： Yan Shi Jiange kou Zhenlei Chen Yixuan Wang Qing Guo School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China

Exoskeletons generally require accurate dynamic models to design the model-based controller conveniently under the human-robot interaction ***,due to unknown model parameters such as the mass,moment of inertia and mechanical size,the dynamic model of exoskeletons is difficult to ***,an enhanced whale optimization algorithm(EWOA)is proposed to identify the exoskeleton model ***,the periodic excitation trajectories are designed by finite Fourier series to input the desired position demand of exoskeletons with mechanical physical *** a backstepping controller based on the identified model is adopted to improve the human-robot wearable comfortable performance under cooperative ***,the proposed Model parameters identification and control are verified by a two-DOF exoskeletons *** knee joint motion achieves a steady-state response after 0.5 ***,the position error of hip joint response is less than 0.03 rad after 0.9 *** addition,the steady-state human-robot interaction torque of the two joints is constrained within 15 N·*** research proposes a whale optimization algorithm to optimize the excitation trajectory and identify model ***,an enhanced mutation strategy is adopted to avoid whale evolution’s unsatisfactory local optimal value.

关键词： Parameter identification Enhanced whale optimization algorithm(EWOA) Backstepping Human-robot interaction Lower limb exoskeleton