As a driving element,the spiral torsion spring can control the release velocity by the optimization design of spring parameters and be used for separation devices,which is conducive to unlocking synchronicity and low-...As a driving element,the spiral torsion spring can control the release velocity by the optimization design of spring parameters and be used for separation devices,which is conducive to unlocking synchronicity and low-shock of the separation. On the basis of analyzing the performance requirements of the spiral torsion spring in a spacecraft device,the optimization design model of the spiral torsion spring is given, which takes the spiral torsion spring's length,width and thickness as the optimization variables,and the minimum volume as the optimization objective. The model considers output torque,strength,the maximal resetting load,holding force,and low shock as constraint conditions. A case is given to analyze the proposed model. The analysis results show the optimization scheme decreases the volume of the spiral torsion spring and meets the performance requirements of the separation device.展开更多
The safety and reliability of space connection and separation device has become a key issue due to the increasing service span of deep space exploration mission.The long-term preload relaxation(a key failure mode)of c...The safety and reliability of space connection and separation device has become a key issue due to the increasing service span of deep space exploration mission.The long-term preload relaxation(a key failure mode)of connection and separation devices is focused in this paper.A series of tests have been designed and implemented to investigate the preload relaxation regulation and a comprehensive method has been constructed to analyze and predict the reliable lifetime of the device.The two-stage preload relaxation law of the device is found and reasonably considered.Due to the different relaxation mechanism,the first-stage preload relaxation is assessed based on the working-condition test results,and the second-stage preload relaxation is characterized by accelerated test results.Finally,the service reliability and reliable life are evaluated.The experiment and assessment results demonstrate the reasonability and effectiveness of the proposed method which can achieve long-service reliability analysis for space connection and separation device within limited time.展开更多
Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glas...Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glass capillary microfluidic device（GCMD）. Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen. The emulsion was added into the GCMD to fabricate the（water-in-oil）-in-water double emulsion droplets. The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets. Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase. The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs. The meso-macropores in these beads were generated by PIPS because of the presence of porogen and gigapores obtained from the emulsion-template. The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry（MIP）. New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the carrier continuous phase. The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.展开更多
To investigate the influence of design parameters on the performance of separation device,the structure and air-operated test of a low-shock separation device are introduced and analyzed in this paper.According to the...To investigate the influence of design parameters on the performance of separation device,the structure and air-operated test of a low-shock separation device are introduced and analyzed in this paper.According to the law of energy conservation and aerodynamics,a mathematical model is built.Because the preload used to ensure the connection reliability has the discreteness,which will influence the separation process,the influence of preload discreteness on the air-operated separation process is simulated and tested.Simulation results are consistent with the experimental results.It is shown that the change of preload has an obvious influence on the separation process.The study is useful for the design and optimization of separation device.展开更多
Non-pyrotechnic separation devices have been fully recognized for their high performance and high reliability.The focus of this paper is mainly around the development of memory alloy satellite and rocket separation de...Non-pyrotechnic separation devices have been fully recognized for their high performance and high reliability.The focus of this paper is mainly around the development of memory alloy satellite and rocket separation devices.Due to the increasing demand for small-sized rockets and satellites,some suggestions and experiments for developing this new type of non-pyrotechnic device are proposed and conducted.展开更多
A three-terminal device based on electronic phase separated manganites is suggested to produce high performance resistive switching. Our Monte Carlo simulations reveal that the conductive filaments can be formed/annih...A three-terminal device based on electronic phase separated manganites is suggested to produce high performance resistive switching. Our Monte Carlo simulations reveal that the conductive filaments can be formed/annihilated by reshaping the ferromagnetic metal phase domains with two cross-oriented switching voltages. Besides, by controlling the high resistance state（HRS） to a stable state that just after the filament is ruptured, the resistive switching remains stable and reversible, while the switching voltage and the switching time can be greatly reduced.展开更多
Onboard air separation devices,based on hollow fiber membranes,are traditionally used for the optimization of aircraft fuel tank inerting systems.In the present study,a set of tests have been designed and executed to ...Onboard air separation devices,based on hollow fiber membranes,are traditionally used for the optimization of aircraft fuel tank inerting systems.In the present study,a set of tests have been designed and executed to assess the air separation performances of these systems for different air inlet temperatures(70°C∼110°C),inlet pressures(0.1∼0.4 MPa),volume flow rates of nitrogen-enriched air(NEA)(30∼120 L/min)and flight altitudes(1.5∼18 km).In particular,the temperature,pressure,volume flow rate,and oxygen concentration of air,NEA and oxygen-enriched air(OEA)have been measured.The experimental results show that the oxygen concentration of NEA,air separation coefficient,and nitrogen utilization coefficient decrease with the rising of air inlet temperature,air inlet pressure,and flight altitude.The effect of air inlet pressure on the above three parameters is significant,while the influence of air inlet temperature and flight altitude is relatively small.展开更多
Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks th...Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable production.After structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production.展开更多
In this paper,two new concepts—“main out-of-step mode” and “minor out-of-step mode”—are proposed for power system reliability analysis. Large-scale power system studies found that out-of-step generator groups ma...In this paper,two new concepts—“main out-of-step mode” and “minor out-of-step mode”—are proposed for power system reliability analysis. Large-scale power system studies found that out-of-step generator groups may have characteristics of the main out-of-step mode and the minor out-of-step mode. The generator groups with main out-of-step modes can determine the out-of-step interface of the large-scale power system,while generators with the minor out-of-step modes cannot play such a role. Therefore,the method of capturing the out-of-step interface by seeking the lowest voltage point(the out-of-step center) can only group the generators with the main out-of-step modes,and may fail to combine the generators with the minor out-of-step modes into proper coherent generator groups. Thus,it is necessary in engineering applications to equip the generators that are likely to have the characteristics of the minor out-of-step modes with separation devices based on off-line simulation studies in order to reduce the risk of further accidents caused by these generators after system separation.展开更多
The article improves the quality of raw cotton by creating a new transfer device structure for the transportation of cotton in long-distance riots, located in the main building of the ginnery. Both foreign and domesti...The article improves the quality of raw cotton by creating a new transfer device structure for the transportation of cotton in long-distance riots, located in the main building of the ginnery. Both foreign and domestic separator cleaners have been studied. Experiments were carried out on prototype transfer device and the results were obtained. The cleaning efficiency was determined by sampling the cotton entering the separator in the moving device and exiting after the inclined vibrating mesh surface installed after the separator.展开更多
Walnut shell-kernel separation after cracking is crucial for providing raw materials for further processing.However,impurities and losses during separation limit complete separation.To address this,a two-stage tandem ...Walnut shell-kernel separation after cracking is crucial for providing raw materials for further processing.However,impurities and losses during separation limit complete separation.To address this,a two-stage tandem separation device was designed and optimized.Computational fluid dynamics(CFD)was used to analyze the effects of four bent duct structures on the flow field.Response surface methodology(RSM)and artificial neural networks(ANN)were employed to predict separation performance under various conditions.Both models accurately predicted performance,with ANN showing superior predictive ability.The optimal design was determined using non-dominated sorting genetic algorithm-II(NSGA-II)and technique for order preference by similarity to an ideal solution(TOPSIS):the inclination of the first stage deflector plate(x_(1))was 39°,the inclination of the second stage deflector plate(x_(2))was 36°,the wind speed of the first stage fan(x_(3))was 21 m/s,and the wind speed of the second stage fan(x_(4))was 13.5 m/s;impurity rate(y_(1))was 4.51%,and loss rate(y_(2))was 6.62%.Compared with traditional single-stage devices,the optimized device reduced impurity rate by 73.98%to 77.55%and loss rate by 9.44%to 53.96%,significantly improving separation efficiency and quality.This study provides theoretical guidance for designing and optimizing shell-kernel separation devices.展开更多
During combined peanut harvesting operations,the separating device plays a crucial role in determining peanuts’damage rate and impurity content.In order to enhance the quality and efficiency of peanut harvesting,this...During combined peanut harvesting operations,the separating device plays a crucial role in determining peanuts’damage rate and impurity content.In order to enhance the quality and efficiency of peanut harvesting,this study investigates the separating device of a two-ridge and four-row half-feeder combine harvester.Firstly,the operating principle of the separating device was analyzed,and a combined air-and-screen separating device was selected.Secondly,based on the movement state of peanut pod impurities in different sections of the separating device surface,the theoretical analysis of peanut pod impurity movement was carried out,and the peanut pod impurity dynamics model was constructed.At the same time,CFD software was used to analyze the airflow field inside the separating device.Moreover,the test factors affecting the separating effect were explored:fan wind speed,separating device surface inclination,and vibration frequency.The optimal working parameters of the device were determined as follows:a fan wind speed of 8.9 m/s,a separating device surface inclination angle of 8.3°concerning the horizontal,and a separating device vibration frequency of 7.2 Hz.The impurity content rate of the peanut pods was 1.48%,and the damage rate of the separating device was 1.61%.Finally,the impurity content of peanuts in the validation experiment was 1.53%,and the peanut damage rate was 1.68%.The effectiveness of the separating device operation was verified through field tests.The potential for further research on peanut harvesters is highlighted based on the findings of this study.展开更多
This article deals with the characteristics of weakly swirling turbulent flow field in a Turbid Water Hydraulic Separation Device （TWHSD） through experimental and numerical researches. The flow field was measured by...This article deals with the characteristics of weakly swirling turbulent flow field in a Turbid Water Hydraulic Separation Device （TWHSD） through experimental and numerical researches. The flow field was measured by PIV, which provided streamlines, vortex structure, vorticity and velocity distribution in different test planes in the TWHSD. On the basis of the experimental results, the tangential and radial velocity distributions of the swirling flow field were obtained. Meanwhile, the numerical simulations were conducted with the RNG κ-ε and RSM turbulence models, respectively. According to the experimental and numerical results, the characteristics of the clear water flow field inside the TWHSD were determined. In view of simulation accuracy and time consumption, it is suggested to apply the RNG κ-ε model instead of the RSM model, which is more time consuming, to make further study on two-phases flow fields in the device.展开更多
基金Natural Science Foundation of Liaoning Province,China(No.2015020121)Research Fund for the Doctoral Program of Higher Education of China(No.20122125120013)the Fundamental Research Funds for the Central Universities,China(Nos.3132015087,3132014303)
文摘As a driving element,the spiral torsion spring can control the release velocity by the optimization design of spring parameters and be used for separation devices,which is conducive to unlocking synchronicity and low-shock of the separation. On the basis of analyzing the performance requirements of the spiral torsion spring in a spacecraft device,the optimization design model of the spiral torsion spring is given, which takes the spiral torsion spring's length,width and thickness as the optimization variables,and the minimum volume as the optimization objective. The model considers output torque,strength,the maximal resetting load,holding force,and low shock as constraint conditions. A case is given to analyze the proposed model. The analysis results show the optimization scheme decreases the volume of the spiral torsion spring and meets the performance requirements of the separation device.
基金supported by the National Natural Science Foundation of China(No.11872085)。
文摘The safety and reliability of space connection and separation device has become a key issue due to the increasing service span of deep space exploration mission.The long-term preload relaxation(a key failure mode)of connection and separation devices is focused in this paper.A series of tests have been designed and implemented to investigate the preload relaxation regulation and a comprehensive method has been constructed to analyze and predict the reliable lifetime of the device.The two-stage preload relaxation law of the device is found and reasonably considered.Due to the different relaxation mechanism,the first-stage preload relaxation is assessed based on the working-condition test results,and the second-stage preload relaxation is characterized by accelerated test results.Finally,the service reliability and reliable life are evaluated.The experiment and assessment results demonstrate the reasonability and effectiveness of the proposed method which can achieve long-service reliability analysis for space connection and separation device within limited time.
文摘Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glass capillary microfluidic device（GCMD）. Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen. The emulsion was added into the GCMD to fabricate the（water-in-oil）-in-water double emulsion droplets. The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets. Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase. The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs. The meso-macropores in these beads were generated by PIPS because of the presence of porogen and gigapores obtained from the emulsion-template. The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry（MIP）. New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the carrier continuous phase. The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.
文摘To investigate the influence of design parameters on the performance of separation device,the structure and air-operated test of a low-shock separation device are introduced and analyzed in this paper.According to the law of energy conservation and aerodynamics,a mathematical model is built.Because the preload used to ensure the connection reliability has the discreteness,which will influence the separation process,the influence of preload discreteness on the air-operated separation process is simulated and tested.Simulation results are consistent with the experimental results.It is shown that the change of preload has an obvious influence on the separation process.The study is useful for the design and optimization of separation device.
文摘Non-pyrotechnic separation devices have been fully recognized for their high performance and high reliability.The focus of this paper is mainly around the development of memory alloy satellite and rocket separation devices.Due to the increasing demand for small-sized rockets and satellites,some suggestions and experiments for developing this new type of non-pyrotechnic device are proposed and conducted.
基金supported by the National Basic Research Program of China(Grant No.2011CB922101)the National Natural Science Foundation of China(Grant Nos.51301084 and 11234005)+1 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20130576)Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1243)
文摘A three-terminal device based on electronic phase separated manganites is suggested to produce high performance resistive switching. Our Monte Carlo simulations reveal that the conductive filaments can be formed/annihilated by reshaping the ferromagnetic metal phase domains with two cross-oriented switching voltages. Besides, by controlling the high resistance state（HRS） to a stable state that just after the filament is ruptured, the resistive switching remains stable and reversible, while the switching voltage and the switching time can be greatly reduced.
基金This project is supported by the Fund of Natural Science Project of Hunan Province,China,with the Item No.2020JJ5393Education Department of Hunan Province,China,with the Item No.18C0735.
文摘Onboard air separation devices,based on hollow fiber membranes,are traditionally used for the optimization of aircraft fuel tank inerting systems.In the present study,a set of tests have been designed and executed to assess the air separation performances of these systems for different air inlet temperatures(70°C∼110°C),inlet pressures(0.1∼0.4 MPa),volume flow rates of nitrogen-enriched air(NEA)(30∼120 L/min)and flight altitudes(1.5∼18 km).In particular,the temperature,pressure,volume flow rate,and oxygen concentration of air,NEA and oxygen-enriched air(OEA)have been measured.The experimental results show that the oxygen concentration of NEA,air separation coefficient,and nitrogen utilization coefficient decrease with the rising of air inlet temperature,air inlet pressure,and flight altitude.The effect of air inlet pressure on the above three parameters is significant,while the influence of air inlet temperature and flight altitude is relatively small.
基金supported by National Natural Science Foundation(52204050)Sichuan Science and Technology Program(2021ZHCG0013,22ZDYF3009)。
文摘Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable production.After structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production.
基金Project (No. 50277034) supported by the National Natural ScienceFoundation of China
文摘In this paper,two new concepts—“main out-of-step mode” and “minor out-of-step mode”—are proposed for power system reliability analysis. Large-scale power system studies found that out-of-step generator groups may have characteristics of the main out-of-step mode and the minor out-of-step mode. The generator groups with main out-of-step modes can determine the out-of-step interface of the large-scale power system,while generators with the minor out-of-step modes cannot play such a role. Therefore,the method of capturing the out-of-step interface by seeking the lowest voltage point(the out-of-step center) can only group the generators with the main out-of-step modes,and may fail to combine the generators with the minor out-of-step modes into proper coherent generator groups. Thus,it is necessary in engineering applications to equip the generators that are likely to have the characteristics of the minor out-of-step modes with separation devices based on off-line simulation studies in order to reduce the risk of further accidents caused by these generators after system separation.
文摘The article improves the quality of raw cotton by creating a new transfer device structure for the transportation of cotton in long-distance riots, located in the main building of the ginnery. Both foreign and domestic separator cleaners have been studied. Experiments were carried out on prototype transfer device and the results were obtained. The cleaning efficiency was determined by sampling the cotton entering the separator in the moving device and exiting after the inclined vibrating mesh surface installed after the separator.
基金This work has been financially supported and encouraged by the National Science Foundation for Young Scientists of China(Grant No.12002229)the Key R&D Program Projects of Xinjiang Uygur Autonomous Region(2024B02017)+2 种基金the Bingtuan Science and Technology Program(Grant No.2022CB008,2018CB014)the Science and Technology Research Project of the Presidential Foundation of Tarim University(Grant No.TDZKBS202414)the National Forestry and Grassland Equipment Science and Technology Innovation Park’s“Challenge System”Major Breakthrough Project(2024YG06).
文摘Walnut shell-kernel separation after cracking is crucial for providing raw materials for further processing.However,impurities and losses during separation limit complete separation.To address this,a two-stage tandem separation device was designed and optimized.Computational fluid dynamics(CFD)was used to analyze the effects of four bent duct structures on the flow field.Response surface methodology(RSM)and artificial neural networks(ANN)were employed to predict separation performance under various conditions.Both models accurately predicted performance,with ANN showing superior predictive ability.The optimal design was determined using non-dominated sorting genetic algorithm-II(NSGA-II)and technique for order preference by similarity to an ideal solution(TOPSIS):the inclination of the first stage deflector plate(x_(1))was 39°,the inclination of the second stage deflector plate(x_(2))was 36°,the wind speed of the first stage fan(x_(3))was 21 m/s,and the wind speed of the second stage fan(x_(4))was 13.5 m/s;impurity rate(y_(1))was 4.51%,and loss rate(y_(2))was 6.62%.Compared with traditional single-stage devices,the optimized device reduced impurity rate by 73.98%to 77.55%and loss rate by 9.44%to 53.96%,significantly improving separation efficiency and quality.This study provides theoretical guidance for designing and optimizing shell-kernel separation devices.
基金financially sponsored by the Key R&D Program(Major Science and Technology Innovation Project)in Shandong Province(Grant No.2021CXGC010813)the National Key Research and Development Program(Grant No.2022YFD2300100).
文摘During combined peanut harvesting operations,the separating device plays a crucial role in determining peanuts’damage rate and impurity content.In order to enhance the quality and efficiency of peanut harvesting,this study investigates the separating device of a two-ridge and four-row half-feeder combine harvester.Firstly,the operating principle of the separating device was analyzed,and a combined air-and-screen separating device was selected.Secondly,based on the movement state of peanut pod impurities in different sections of the separating device surface,the theoretical analysis of peanut pod impurity movement was carried out,and the peanut pod impurity dynamics model was constructed.At the same time,CFD software was used to analyze the airflow field inside the separating device.Moreover,the test factors affecting the separating effect were explored:fan wind speed,separating device surface inclination,and vibration frequency.The optimal working parameters of the device were determined as follows:a fan wind speed of 8.9 m/s,a separating device surface inclination angle of 8.3°concerning the horizontal,and a separating device vibration frequency of 7.2 Hz.The impurity content rate of the peanut pods was 1.48%,and the damage rate of the separating device was 1.61%.Finally,the impurity content of peanuts in the validation experiment was 1.53%,and the peanut damage rate was 1.68%.The effectiveness of the separating device operation was verified through field tests.The potential for further research on peanut harvesters is highlighted based on the findings of this study.
基金the National Natural Science Foundation of China (Grant No. 50469003)the University Science and Research Key Project of Xinjiang Uygur Autonomous Region(XJEDU 2004121)
文摘This article deals with the characteristics of weakly swirling turbulent flow field in a Turbid Water Hydraulic Separation Device （TWHSD） through experimental and numerical researches. The flow field was measured by PIV, which provided streamlines, vortex structure, vorticity and velocity distribution in different test planes in the TWHSD. On the basis of the experimental results, the tangential and radial velocity distributions of the swirling flow field were obtained. Meanwhile, the numerical simulations were conducted with the RNG κ-ε and RSM turbulence models, respectively. According to the experimental and numerical results, the characteristics of the clear water flow field inside the TWHSD were determined. In view of simulation accuracy and time consumption, it is suggested to apply the RNG κ-ε model instead of the RSM model, which is more time consuming, to make further study on two-phases flow fields in the device.
