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Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0732-0

摘要： To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface, a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface. To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush, the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted. The parameter calibration of the sampled particles is studied first, and the calibrated particle parameters are used in the numerical simulation of the sampling process. The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds, and the effects of different parameter settings on the sampling efficiency are analyzed. In addition, a set of rotating symmetrical sampling wheel brush devices is built for the ground test, and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process. The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results. Results indicate that when the rotating speed of the wheel brush is faster, the sampling efficiency is higher, and the driving torque required for the sampling wheel brush is greater. Moreover, a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition, and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method. This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler, which provides important reference value and engineering significance.

关键词： asteroid sampling     wheel brush sampler     discrete element method     parameter calibration     experimental research    

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Experimental research on cyclone performance at high temperature

LI Wenqi, CHEN Jianyi

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 310-317 doi: 10.1007/s11465-007-0055-1

摘要： To predict the influence of operating temperatures on cyclone performance, an experimental investigation was conducted on particle separation in a reverse flow, tangential volute-inlet cyclone separator with a diameter of 300 mm and with air heated up to 973 K. The test powder silica has a mass median diameter of 10 um, while inlet velocity range was 12-36 m/s. Both the separation efficiency and pressure drop of the cyclone were measured as a function of the inlet velocity and operating temperature. At the same inlet velocity, both the separation efficiency and pressure drop decrease with increasing temperature. In addition, optimum inlet velocity, at which the cyclone has its highest separation efficiency, tends to increase with a rise in temperature. An analysis on our own data and published results has shown that the fractional efficiency of a cyclone is a definite function of dimensionless numbers such as the Stokes number, the Reynolds number, the Froude number, dimensionless cyclone inlet area, and dimensionless outlet diameter. A nondimensional experimental correlation of the cyclone performance, including the influence of temperature, was obtained on the basis of our own previous work. The prediction of the influence of temperature on separation efficiencies and pressure drops is in fairly good agreement with experimental results.

关键词： diameter     definite function     nondimensional experimental     cyclone performance     influence    

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THAI experimental research on hydrogen risk and source term related safety systems

《能源前沿（英文）》 2021年 第15卷 第4期   页码 887-915 doi: 10.1007/s11708-021-0789-1

摘要： In the defense-in-depth concept employed for the safety of nuclear installations, maintaining integrity of containment as the last barrier is of high importance to limit the release of radioactivity to the environment in case of a severe accident. The active and passive safety systems implemented in containments of light water reactors (LWRs) are designed to limit the consequences of such accidents. Assessing the performance and reliability of such systems under accident conditions is critical to the safety of nuclear installations.

关键词： severe accident     containment     safety     mitigation     H2 risk     source term    

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Experimental research on compaction characteristics of aeolian sand

YUAN Yuqing, WANG Xuancang, ZHOU Xin

《结构与土木工程前沿（英文）》 2008年 第2卷 第4期   页码 359-365 doi: 10.1007/s11709-008-0053-3

摘要： Unlike other road materials, aeolian sand has some compaction characteristics that are key factors in construction qualities of highway in the desert. In order to study the characteristics, a series of laboratory and field tests were performed, including sieve analysis, standard modified compaction, vibrating compaction and field test. By analyzing the sieve analysis test data, it was found that the gradation of aeolian sand was bad, with fine grains whose diameters mostly ranged from 0.25 mm to 0.074 mm. Then, from the laboratory compaction test results, a compaction curve similar to the horizontally-written letter S was obtained. That was quite different from the other kinds of road materials. There were two peak values in the curve with the increase of water content, which was the special characteristic of aeolian sand: to be well compacted whether it was dry or wet. Also, according to laboratory vibrating test results, the best vibrating frequency range was proposed. It was from 45 Hz to 50 Hz. Moreover, some field compaction tests were carried out. On the construction site of the highway, the aeolian sand subgrade was compacted in the condition of natural water content with optimizing construction machines. Its compaction degree reached 96%, meeting the current specifications. At last, comparative studies were carried through with electron microscope. It was shown that the microstructure of compacted dry aeolian sand is much denser than that of the natural one in the field test.
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Development of an experimental platform for research in energy and electrical machine control

Ali HMIDET, Rachid DHIFAOUI, Driss SAIDANI, Othman HASNAOUI,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 366-375 doi: 10.1007/s11708-010-0106-x

摘要： This paper presents the development of a test bench dedicated for electrical machines and energy control, as realized by the research team of the Power Systems and Electrical Machines Laboratory (RME) of the National Institute of Applied Sciences and Technology (INSAT) in Tunisia. The principal components of the proposed test bench are explained, and the respective characteristics are given. This paper focuses on mounting low-cost sensors and developing reliable scientific results. The relevant obtained results in photovoltaic (PV) and wind energy fields, power measurement and control, as well as alternating current (AC) machine drives are likewise presented. These are supported by two signal processing controller boards based on Technosoft MCK240 and dSPACE DS1104 kits. In the wind energy field, some results relative to Self Excited Induction Generator dedicated to supplying isolated sites are discussed; in addition, water pumping is discussed for PV energy. In the AC drives area, the results of a closed loop control are presented using a developed direct voltage control (DVC) scheme implemented on dSPACE DS1104. Maps and interesting details of some realized sensors are also presented.

关键词： test bench     induction motor     solar energy     wind energy     AC/DC/AC converter     sensors and power measurements    

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Theoretical analysis and actual experimental research on static characteristics of suspendome structure

CHEN Zhihua, YAN Xiangyu, SUN Ruirui, FENG Zhenchang, QIN Yali, ZHAO Jianbo

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 286-292 doi: 10.1007/s11709-007-0037-8

摘要： The suspendome used as the roof of the VIP hall in Tianjin Museum was analyzed by ANASYS under the assumptions of hinged joints and rigid joints in up chord, respectively, and the results show that the member force and nodal displacement under the two assumptions have little difference. Thus, it is attained that the suspendome can be analyzed with the assumption of hinged joints. A full-scale test on the suspendome with half-cable and half-pipe was carried out. The loading system, arrangement of measuring points, and the test procedures are introduced. Also, a test on steel wire ropes for elastic module was carried out. The experimental and theoretical values of member forces and nodal displacements were compared and it showed that they accord well with each other under low-level load. While under high-level load, the experimental value was bigger than the theoretical value due to the influence of the test environment. With the increase of the load, tension of outside cables and looseness of inside cables occurred, which indicated that the prestressing value in inside cables should be properly assigned. Both the experimental and theoretical results verify that the suspendome has a wide application prospect with the advantages of perfect mechanical characteristics, low steel consumption, convenient construction and low cost.

关键词： Tianjin     influence     displacement     high-level     low-level    

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Design and Experimental Research on a New Pipe Rupture Valve

HU Guo-liang, XU Bing, YANG Hua-yong, ZHANG Yi-ding

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 26-32 doi: 10.1007/s11465-005-0009-4

摘要：

A new pipe rupture valve for hydraulic elevator is designed. Mathematical models established for the hydraulic elevator system are used in numerical simulations on the Simulink environment of Matlab kits. The effects of different viscous damping diameters, inlet pressures of pipe rupture valve, and elevator loads on the hydraulic elevator system s dynamic performance are analyzed. Experimental research is also carried out using a hydraulic elevator experiment rig. The numerical simulations accord with experimental results in general. Dynamic performance indexes are assessed by the EN81-2 standard. The results show that the newly designed pipe rupture valve meets the designing requirement for hydraulic elevators.

关键词： Mathematical     designing requirement     numerical     hydraulic elevator     EN81-2 standard    

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Numerical and experimental research of the characteristics of concentration solar cells

Zilong WANG, Hua ZHANG, Binlin DOU, Weidong WU, Guanhua ZHANG

《能源前沿（英文）》 2021年 第15卷 第2期   页码 279-291 doi: 10.1007/s11708-019-0637-8

摘要： The development of automatic tracking solar concentrator photovoltaic systems is currently attracting growing interest. High concentration photovoltaic systems (HCPVs) combining triple-junction InGaP/lnGaAs/Ge solar cells with a concentrator provide high conversion efficiencies. The mathematical model for triple-junction solar cells, having a higher efficiency and superior temperature characteristics, was established based on the one-diode equivalent circuit cell model. A paraboloidal concentrator with a secondary optic system and a concentration ratio in the range of 100X–150X along with a sun tracking system was developed in this study. The GaInP/GalnAs/Ge triple-junction solar cell, produced by AZUR SPACE Solar Power, was also used in this study. The solar cells produced by Shanghai Solar Youth Energy (SY) and Shenzhen Yinshengsheng Technology Co. Ltd. (YXS) were used as comparison samples in a further comparative study at different concentration ratios (200X–1000X). A detailed analysis on the factors that influence the electrical output characteristics of the InGaP/lnGaAs/Ge solar cell was conducted with a dish-style concentrating photovoltaic system. The results show that the short-circuit current ( ) and the open-circuit voltage ( ) of multi-junction solar cells increases with the increasing concentration ratio, while the cell efficiency ( ) of the solar cells increases first and then decreases with increasing concentration ratio. With increasing solar cell temperature, increases, while and decrease. A comparison of the experimental and simulation results indicate that the maximum root mean square error is less than 10%, which provides a certain theoretical basis for the study of the characteristics of triple-junction solar cell that can be applied in the analysis and discussion regarding the influence of the relevant parameters on the performance of high concentration photovoltaic systems.

关键词： concentration     three-junction solar cell     mathematical model     electrical properties     solar energy    

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Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 606-624 doi: 10.1007/s11709-023-0925-6

摘要： A novel cambered surface steel tube damper (CSTD) with a cambered surface steel tube and two concave connecting plates is proposed herein. The steel tube is the main energy dissipation component and comprises a weakened segment in the middle, a transition segment, and an embedded segment. It is believed that during an earthquake, the middle weakened segment of the CSTD will be damaged, whereas the reliability of the end connection is ensured. Theoretical and experimental studies are conducted to verify the effectiveness of the proposed CSTD. Formulas for the initial stiffness and yield force of the CSTD are proposed. Subsequently, two CSTD specimens with different steel tube thicknesses are fabricated and tested under cyclic quasi-static loads. The result shows that the CSTD yields a stable hysteretic response and affords excellent energy dissipation. A parametric study is conducted to investigate the effects of the steel tube height, diameter, and thickness on the seismic performance of the CSTD. Compared with equal-stiffness design steel tube dampers, the CSTD exhibits better energy dissipation performance, more stable hysteretic response, and better uniformity in plastic deformation distributions.

关键词： cambered surface steel tube damper     energy dissipation capacity     finite element model     hysteretic performance     parametric study    

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Numerical simulation and experimental research on heat transfer and flow resistance characteristics of

Shaozhi ZHANG, Xiao NIU, Yang LI, Guangming CHEN, Xiangguo XU

《能源前沿（英文）》 2020年 第14卷 第2期   页码 267-282 doi: 10.1007/s11708-020-0662-7

摘要： The asymmetric plate heat exchanger (APHE) has the possibility of achieving balanced pressure drops on both hot and cold sides for situations with unbalanced flow, which may in turn enhance the heat transfer. In this paper, the single-phase water flow and heat transfer of an APHE consisted of two types of plates are numerically (400≤ ≤12000) and experimentally (400≤ ≤3400) investigated. The numerical model is verified by the experimental results. Simulations are conducted to study the effects of , an asymmetric index proposed to describe the geometry of APHEs. The correlations of the Nusselt number and friction factor in the APHEs are determined by taking and working fluids into account. It is found that an optimal exists where the pressure drops are balanced and the heat transfer area reaches the minimum. The comparison between heat transfer and flow characteristics of the APHEs and the conventional plate heat exchanger (CPHE) is made under various flow rate ratios of the hot side and the cold side and different allowable pressure drops. The situations under which APHE may perform better are identified based on a comprehensive index .

关键词： plate heat exchanger     asymmetric     simulation     correlation     heat transfer enhancement    

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Experimental research on seismic behavior of recycled concrete frame under varying cyclic loading

SUN Yuedong, XIAO Jianzhuang, ZHOU Deyuan

《结构与土木工程前沿（英文）》 2008年 第2卷 第4期   页码 302-308 doi: 10.1007/s11709-008-0050-6

摘要： A study is conducted on the seismic behavior of one natural concrete frame and two recycled concrete frames with 100% recycled coarse aggregate whose scales are 1:2 entirely, and a comparative study is conducted under low-reversed cyclic lateral loading and different vertical loading. This work aims to estimate the failure mechanism, hysteresis loops, displacement ductility, deterioration of strength and stiffness and energy dissipation of recycled concrete frames under low-reversed cyclic loading as well as the influence of different vertical loading. Analysis on the basis of the experiment proves that it is entirely feasible to apply recycled concrete to practical engineering for the sake of its good seismic behaviors. Theoretical base is provided for further study and practical application of recycled concrete structure.

关键词： different     aggregate     stiffness     practical application     % recycled    

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Experimental research on the creep behavior and bearing capacity of repeatedly prestressed concrete beam

SHAO Xudong, LI Lifeng, YANG Jianjun

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 305-311 doi: 10.1007/s11709-007-0040-0

摘要： In the prestress tensioning process of medium or short span prestressed concrete beam bridges, there are always many serious problems, such as the camber of straight beam being too large, curved beam going crosswise, and columns of rigid beam bridge cracking, that can be commonly seen because of its greater additional stress in prestressing. To solve the above problems, a new concept of repeatedly prestressed bridge structure was innovatively proposed in this work. It was proved, through theoretical and experimental comparison between this new structure and the traditional prestressed structure, that the application of repeated prestressing technology can greatly improve the mechanical and deformational performance of the low height beam during construction and long-term use. Furthermore, a kind of computational formula to calculate creep strain and deformation due to repeated prestressing in terms of time was derived in this paper and the bearing capacity of this new structure has been tested. Finally, the work concludes that there is a bright application prospect for this new structure for medium and short span prestressed beam bridges to control deformations.

关键词： computational     cracking     technology     prestressed concrete     application prospect    

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Experimental research on the mechanical property of prestressing steel wire during and after heating

ZHENG Wenzhong, HU Qiong, ZHANG Haoyu

《结构与土木工程前沿（英文）》 2007年 第1卷 第2期   页码 247-254 doi: 10.1007/s11709-007-0031-1

摘要： The mechanical property of prestressing steel wire during and after heating is the key factor in the design of fire resistance and after-fire damage evaluation of prestressed structures. Tensile experiment of 16 prestressing steel wires ( = 1770 N/mm, = 5 mm, low relaxation of stress) at high temperature and tensile experiment of 14 prestressed steel wires after heating are carried out. According to the experiment, the shapes of stress-strain curves of steel wire at high temperature go smooth and the mechanical property indexes of the steel wire such as strength, modulus of elasticity, etc., degenerate continuously as temperature increased. According to the experiment after heating, the mechanical property of steel wire varies little when the highest temperature that the steel wire has ever been heated to is lower than 300vH; while the stress-strain curves of steel wire become more ductile and the mechanical property indexes of the steel wire degenerate gradually when the highest temperature is higher than 300vH. By applying the theory of viscoelastic mechanics, stress-strain curves of steel wire at high temperatures without loading rate influence are obtained. The law of mechanical property indexes of the wire is presented. The mathematical models of the stress-strain relationship of the pre-stressed steel wire are established. All can serve as basic data for the analysis of fire resistance and after-fire damage evaluation of pre-stressed structures.
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Experimental research on ductile fracture criterion in metal forming

Song YU, Weiming FENG

《机械工程前沿（英文）》 2011年 第6卷 第3期   页码 308-311 doi: 10.1007/s11465-011-0233-z

摘要：

Ductile fracture criterion is key limitation parameter in material forming. Accuracy predicting surface and internal failure in plastic deformation process affects on the technology design of workpiece and die greatly. Tension, compression, torsion and shearing test on 45# steel are utilized for providing the experimental values of the critical values at fracture, and 11 widely used ductile fracture criterion are selected to simulate the physical experiments and their relative accuracy for predicting and quantifying fracture initiation sites are investigated. The comparing results show that metal forming process under high triaxiality can be estimated successively using both Normalized Cockcroft-latham and the Brozzo ductile fracture criteria, but the Ayada and general Rice-Tracey model work very well for the low triaxiality cases.

关键词： ductile fracture criteria     metal forming process     material experiment     stress triaxiality    

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Experimental research on dynamic operating characteristics of a novel silica gel-water adsorption chiller

WANG Dechang, WU Jingyi, WANG Ruzhu, DOU Weidong

《能源前沿（英文）》 2007年 第1卷 第3期   页码 347-351 doi: 10.1007/s11708-007-0052-4

摘要： A novel silica gel-water adsorption chiller consisting of two adsorption/desorption chambers and an evaporator with one heat-pipe working chamber is experimentally studied. The dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are obtained. The experimental results show that the dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are satisfactory and that the cycle is a novel and effective adsorption cycle. A mass recovery process increases the cyclic adsorption capacity of the system and improves adaptability of the chiller to a low-grade heat source. In addition, the experiment indicates that this novel chiller is highly suitable for an air conditioning system with a low dehumidification requirement or a system with a large cycle flowrate and an industrial cooling water system.

关键词： satisfactory     suitable     recovery     adsorption capacity     thermodynamic    

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标题 作者 时间 类型 操作

Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

期刊论文

Experimental research on cyclone performance at high temperature

LI Wenqi, CHEN Jianyi

期刊论文

THAI experimental research on hydrogen risk and source term related safety systems

期刊论文

Experimental research on compaction characteristics of aeolian sand

YUAN Yuqing, WANG Xuancang, ZHOU Xin

期刊论文

Development of an experimental platform for research in energy and electrical machine control

Ali HMIDET, Rachid DHIFAOUI, Driss SAIDANI, Othman HASNAOUI,

期刊论文

Theoretical analysis and actual experimental research on static characteristics of suspendome structure

CHEN Zhihua, YAN Xiangyu, SUN Ruirui, FENG Zhenchang, QIN Yali, ZHAO Jianbo

期刊论文

Design and Experimental Research on a New Pipe Rupture Valve

HU Guo-liang, XU Bing, YANG Hua-yong, ZHANG Yi-ding

期刊论文

Numerical and experimental research of the characteristics of concentration solar cells

Zilong WANG, Hua ZHANG, Binlin DOU, Weidong WU, Guanhua ZHANG

期刊论文

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

期刊论文

Numerical simulation and experimental research on heat transfer and flow resistance characteristics of

Shaozhi ZHANG, Xiao NIU, Yang LI, Guangming CHEN, Xiangguo XU

期刊论文

Experimental research on seismic behavior of recycled concrete frame under varying cyclic loading

SUN Yuedong, XIAO Jianzhuang, ZHOU Deyuan

期刊论文

Experimental research on the creep behavior and bearing capacity of repeatedly prestressed concrete beam

SHAO Xudong, LI Lifeng, YANG Jianjun

期刊论文

Experimental research on the mechanical property of prestressing steel wire during and after heating

ZHENG Wenzhong, HU Qiong, ZHANG Haoyu

期刊论文

Experimental research on ductile fracture criterion in metal forming

Song YU, Weiming FENG

期刊论文

Experimental research on dynamic operating characteristics of a novel silica gel-water adsorption chiller

WANG Dechang, WU Jingyi, WANG Ruzhu, DOU Weidong

期刊论文