At present,as China vigorously develops new energy automobiles,the social demand for related talents has increased significantly,so the relevant institutions need to optimize and adjust the talent training mode to hel...At present,as China vigorously develops new energy automobiles,the social demand for related talents has increased significantly,so the relevant institutions need to optimize and adjust the talent training mode to help the development of new energy automobiles.This paper summarizes the existing problems of China’s new energy automobile talent training mode,and analyzes the significance of the virtual simulation-based dual-creation talent training mode of new energy automobile and its specific implementation strategies,in order to provide references for the relevant personnel.展开更多
VOF (volume of fluid) method has been used to make the numerical simulation of freak wave come true. The comparisons between the numerical results and linear theoretical results corresponding to Eq.(5) have been c...VOF (volume of fluid) method has been used to make the numerical simulation of freak wave come true. The comparisons between the numerical results and linear theoretical results corresponding to Eq.(5) have been carried out to show that the numerical results have a better exhibition of nonlinear characteristics. Wavelet analysis method has been adopted to investigate the time-frequency energy spectrum of simulation freak waves and the results reveal strong nonlinear interaction enables energy to be transferred to high harmonics during the progress of its formation. Varying water depth can enhance the nonlinear interaction, making much more energy be transferred to high harmonics and freak waves with higher asymmetry be generated.展开更多
Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste heat.The mineral carbonation of BF slag can not only reduce emissions of s...Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste heat.The mineral carbonation of BF slag can not only reduce emissions of solid waste but also realize the in-situ fixation of CO_2 with low energy consumption if integrated with the waste heat utilization.In this study, based on our previous works, Aspen Plus was employed to simulate and optimize the carbonation process and integrate the process energy.The effects of gehlenite extraction, MgSO_4 carbonation,and aluminum ammonium sulfate crystallization were studied systematically.The simulation results demonstrate that 2.57 kg of BF slag can sequester 1 kg of CO_2, requiring 5.34 MJ of energy(3.3 MJ heat and 2.04 MJ electricity), and this energy includes the capture of CO_2 from industrial flue gases.Approximately 60 kg net CO_2 emission reduction could be achieved for the disposal of one ton of BF slag.In addition, the by-product,aluminum ammonium sulfate, is a high value-added product.Preliminary economic analysis indicates that the profit for the whole process is 1127 CNY per ton of BF slag processed.展开更多
Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recover...Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recovery ventilator and to investigate the effect of the air supply arrangement. Three types of mixing ventilation are chosen for the analysis of coupling ANSYS/FLUENT (a computational fluid dynamics (CFD) program) with TRNSYS (a building energy simulation (BES) software). The adoption of mutual complementary boundary conditions for CFD and BES provides more accurate and complete information of indoor air distribution and thermal performance in buildings. A typical office-space situated in a middle storey is chosen for the analysis. The office-space is equipped with air-conditioners on the ceiling. A heat recovery ventilation system directly supplies flesh air to the office space. Its thermal performance and indoor air distribution predicted by the coupled method are compared under three types of ventilation system. When the supply and return openings for ventilation are arranged on the ceiling, there is no critical difference between the predictions of the coupled method and BES on the energy consumption of HVAC because PID control is adopted for the supply air temperature of the occupied zone. On the other hand, approximately 21% discrepancy for the heat recovery estimation in the maximum between the simulated results of coupled method and BES-only can be obviously found in the floor air supply ventilation case. The discrepancy emphasizes the necessity of coupling CFD with BES when vertical air temperature gradient exists. Our future target is to estimate the optimum design of heat recovery ventilation system to control CO2 concentration by adjusting flow rate of flesh air.展开更多
Non-pillar continuous mining(NPCM) is regarded as a high-efficient, high-level and one-step mining technology, which can be divided into two substopes. Back fill stability status in substope I, which directly influenc...Non-pillar continuous mining(NPCM) is regarded as a high-efficient, high-level and one-step mining technology, which can be divided into two substopes. Back fill stability status in substope I, which directly influence the loss rate and dilution rate, etc, will determine whether the experimental research is successful or not. By employing energy method of limit analysis and finite element numerical simulation method, the critical backfill height was determined under the prerequisite condition of its stability, which put forward theoretical basis for reasonable and correct selection of backfill’s parameters. The result showed that the first backfill could not keep stable for NPCM, while the other was able to.展开更多
We benchmark and analyze the error of energy conservation (EC) scheme in particle-in-cell/Monte Carlo (PIC/MC) algorithms by simulating the radio frequency discharge. The plasma heating behaviors and electron dist...We benchmark and analyze the error of energy conservation (EC) scheme in particle-in-cell/Monte Carlo (PIC/MC) algorithms by simulating the radio frequency discharge. The plasma heating behaviors and electron distributing functions obtained by one-dimensional (1D) simulation are analyzed. Both explicit and implicit algorithms are checked. The results showed that the EC scheme can eliminated the self-heating with wide grid spacing in both cases with a small reduction of the accuracies. In typical parameters, the EC implicit scheme has higher precision than EC explicit scheme. Some "numerical cooling" behaviors are observed and analyzed. Some other errors are also analyzed. The analysis showed that the EC implicit scheme can be used to qualitative estimation of some discharge problems with much less computational resource cost without much loss of accuracies.展开更多
Based on the characteristic of high energy milling and the micromechanics of composite material, a plastic constitutive equation is implemented for milled composite powders. To check the equation, the extrusion of Ti/...Based on the characteristic of high energy milling and the micromechanics of composite material, a plastic constitutive equation is implemented for milled composite powders. To check the equation, the extrusion of Ti/Al composite powders prepared by high energy milling was simulated. It was from the numerical analysis that the predicted extrusion pressure mounted up with milling time and extrusion ratio increasing, which was perfect agreement with experimental results.展开更多
Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upo...Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upon which a series of comparative studies on energy savings with conventional distillation columns are carried out. Furthermore, we present an optimization model of ideal ITCDIC, which can be used to achieve the maximum energy saving and find the optimal design parameters directly. The binary system of benzene-toluene is adopted for the illustrative example of simulation and optimization. The results show that the maximum energy saving of ITCDIC is 52.25% (compared with energy consumption of conventional distillation under the minimum reflux ratio operation); the optimal design parameters are obtained, where the rectifying section pressure and the feed thermal condition are Pr=0.3006 MPa and q=0.5107 respectively.展开更多
Small moving vehicles represent an important category of marine engineering tools and devices(equipment)typically used for ocean resource detection and maintenance of marine rights and interests.The lack of efficient ...Small moving vehicles represent an important category of marine engineering tools and devices(equipment)typically used for ocean resource detection and maintenance of marine rights and interests.The lack of efficient power supply modes is one of the technical bottlenecks restricting the effective utilisation of this type of equipment.In this work,the performance characteristics of a new type of elastic-blade/wave-energy converter(EBWEC)and its core energy conversion component(named wave energy absorber)are comprehensively studied.In particular,computational fluid dynamics(CFD)simulations and experiments have been used to analyze the hydrodynamics and performance characteristics of the EBWEC.The pressure cloud diagrams relating to the surface of the elastic blade were obtained through two-way fluid-solid coupling simulations.The influence of blade thickness and relative speed on the performance characteristics of EBWEC was analyzed accordingly.A prototype of the EBWEC and its bucket test platform were also developed.The power characteristics of the EBWEC were analyzed and studied by using the blade thickness and motion cycle as control variables.The present research shows that the EBWEC can effectively overcome the performance disadvantages related to the transmission shaft torque load and power curve fluctuations of rigid blade wave energy converters(RBWEC).展开更多
The production and energy coupling system is used to mainly present energy flow, material flow, information flow, and their coupling interaction. Through the modeling and simulation of this system, the performance of ...The production and energy coupling system is used to mainly present energy flow, material flow, information flow, and their coupling interaction. Through the modeling and simulation of this system, the performance of energy flow can be analyzed and optimized in the process industry. In order to study this system, the component based hybrid Petri net methodology (CpnHPN) is proposed, synthesizing a number of extended Petri net methods and using the concept of energy place, material place, and information place. Through the interface place in CpnHPN, the component based encapsulation is established, which enables the production and energy coupling system to be built, analyzed, and optimized on the multi-level framework. Considering the block and brief simulation for hybrid system, the CpnHPN model is simulated with Simulink/Stateflow. To illustrate the use of the proposed methodology, the application of CpnHPN in the energy optimization of chlorine balance system is provided.展开更多
Graphene aerogel(GA),as a novel solid material,has shown great potential in engineering applications due to its unique mechanical properties.In this study,the mechanical performance of GA under high-velocity projectil...Graphene aerogel(GA),as a novel solid material,has shown great potential in engineering applications due to its unique mechanical properties.In this study,the mechanical performance of GA under high-velocity projectile impacts is thoroughly investigated using full-atomic molecular dynamics(MD)simulations.The study results show that the porous structure and density are key factors determining the mechanical response of GA under impact loading.Specifically,the impact-induced penetration of the projectile leads to the collapse of the pore structure,causing stretching and subsequent rupture of covalent bonds in graphene sheets.Moreover,the effects of temperature on the mechanical performance of GA have been proven to be minimal,thereby highlighting the mechanical stability of GA over a wide range of temperatures.Finally,the energy absorption density(EAD)and energy absorption efficiency(EAE)metrics are adopted to assess the energy absorption capacity of GA during projectile penetration.The research findings of this work demonstrate the significant potential of GA for energy absorption applications.展开更多
The effect of undercooling DT and the interface energy anisotropy parameter e4 on the shape of the equiaxed dendritic tip has been investigated by using a quantitative phase-field model for solidification of binary al...The effect of undercooling DT and the interface energy anisotropy parameter e4 on the shape of the equiaxed dendritic tip has been investigated by using a quantitative phase-field model for solidification of binary alloys.It was found that the tip radius r increases and the tip shape amplitude coefficient A4 decreases with the increase of the fitting range for all cases.The dendrite tip shape selection parameter sdecreases and then stabilizes with the increase of the fitting range,and sincreases with the increase of e4.The relationship between sand e4 follows a power-law function sµea 4,and a is independent of DT but dependent on the fitting range.Numerical results demonstrate that the predicted sis consistent with the curve of microscopic solvability theory(MST)for e4<0.02,and sobtained from our phase-field simulations is sensitive to the undercooling when e4 is fixed.展开更多
A phase-field model is modified to investigate the grain growth and texture evolution in AZ31 magnesium alloy during stressing at elevated temperatures. The order parameters are defined to represent a physical variabl...A phase-field model is modified to investigate the grain growth and texture evolution in AZ31 magnesium alloy during stressing at elevated temperatures. The order parameters are defined to represent a physical variable of grain orientation in terms of three angles in spatial coordinates so that the grain volume of different order parameters can be used to indicate the texture of the alloy. The stiffness tensors for different grains are different because of elastic anisotropy of the magnesium lattice. The tensor is defined by transforming the standard stiffness tensor according to the angle between the (0001) plane of a grain and the direction of applied stress. Therefore, different grains contribute to different amounts of work under applied stress. The simulation results are well-explained by using the limited experimental data available, and the texture results are in good agreement with the experimental observations. The simulation results reveal that the applied stress strongly influences AZ31 alloy grain growth and that the grain-growth rate increases with the applied stress increasing, particularly when the stress is less than 400 MPa. A parameter (△d) is introduced to characterize the degree of grain-size variation due to abnormal grain growth; the △d increases with applied stress increasing and becomes considerably large only when the stress is greater than 800 MPa. Moreover, the applied stress also results in an intensive texture of the 〈0001〉 axis parallel to the direction of compressive stress in AZ31 alloy after growing at elevated temperatures, only when the applied stress is greater than 500 MPa.展开更多
Although train modeling research is vast, most available simulation tools are confined to city-or trip-scale analysis, primarily offering micro-level simulations of network segments. This paper addresses this void by ...Although train modeling research is vast, most available simulation tools are confined to city-or trip-scale analysis, primarily offering micro-level simulations of network segments. This paper addresses this void by developing the Ne Train Sim simulator for heavy long-haul freight trains on a network of multiple intersecting tracks. The main objective of this simulator is to enable a comprehensive analysis of energy consumption and the associated carbon footprint for the entire train system. Four case studies were conducted to demonstrate the simulator's performance. The first case study validates the model by comparing Ne Train Sim output to empirical trajectory data. The results demonstrate that the simulated trajectory is precise enough to estimate the train energy consumption and carbon dioxide emissions. The second application demonstrates the train-following model considering six trains following each other. The results showcase the model ability to maintain safefollowing distances between successive trains. The next study highlights the simulator's ability to resolve train conflicts for different scenarios. Finally, the suitability of the Ne Train Sim for modeling realistic railroad networks is verified through the modeling of the entire US network and comparing alternative powertrains on the fleet energy consumption.展开更多
Renewable energies are of major interest due to their inexhaustible and clean nature, with minimal impact on the environment. Numerous technological pathways exist in this field, each distinguished by the materials us...Renewable energies are of major interest due to their inexhaustible and clean nature, with minimal impact on the environment. Numerous technological pathways exist in this field, each distinguished by the materials used and their implementation principles. However, the cost-efficiency ratio remains a significant challenge for researchers. Currently, organic materials are gaining popularity due to their relatively low cost. However, their performance, particularly in terms of conversion efficiency, still requires improvements. This study focuses on optimizing the organic photovoltaic cell ITO/MoO3/CARAPA/PCBM/Alq3/Al using SCAPS. Several parameters were considered, such as layer thickness, recombination center density, and doping, to improve the cell’s performance. The optimal parameters obtained include an efficiency of 3%, a fill factor of 81.67%, an open-circuit voltage of 1610 mV, and a short-circuit current of 2.28 mA/cm2. The study also revealed that doping the phenyl-C61-butyric acid methyl ester (PCBM) layer has a significant impact on efficiency and short-circuit current, improving these parameters up to a certain point before causing degradation due to increased recombination. Furthermore, high doping of the tri (8-hydroxyquinoline) aluminum (Alq3) layer improves performance up to a critical threshold, after which degradation is also observed. In contrast, doping the molybdenum trioxide (MoO3) layer does not have a notable impact on cell performance. Regarding the thickness of the active Carapaprocera (CARAPA) and PCBM layers, non-optimal values lead to a decrease in performance. Similarly, an optimal thickness of the Alq3 layer significantly improves efficiency. These results highlight the importance of parameter optimization to maximize the efficiency of organic solar cells.展开更多
Due to the variable output of renewable energy (RE) generation, difficulties of dispatching RE for power system operators could not be avoided. One of possible solutions is the energy storage technology, especially th...Due to the variable output of renewable energy (RE) generation, difficulties of dispatching RE for power system operators could not be avoided. One of possible solutions is the energy storage technology, especially the battery storage system. The large-scale energy storage system is available to support power system reliable flexibility for load following and system frequency regulation. In this paper, the bottlenecks of large-scale solar power generation dispatching and operation in Qinghai grid are discussed, and a new PV-energy storage coordinated dispatching method is proposed for reduction of PV curtailment in Qinghai. Moreover, the validation based on the time-series production simulation is provided using real data from Qinghai. The results indicate that the proposed method can effectively decrease the curtailment of solar power and future vision of large-scale solar power coordinated operation with energy storage system is also presented.展开更多
In this paper, a plug-in hybrid electrical vehicle(PHEV) is taken as the research object, and its dynamic performance and economic performance are taken as the research goals. Battery charge-sustaining(CS) period is d...In this paper, a plug-in hybrid electrical vehicle(PHEV) is taken as the research object, and its dynamic performance and economic performance are taken as the research goals. Battery charge-sustaining(CS) period is divided into power mode and economy mode. Energy management strategy designing methods of power mode and economy mode are proposed. Maximum velocity, acceleration performance and fuel consumption are simulated during the CS period in the AVL CRUISE simulation environment. The simulation results indicate that the maximum velocity and acceleration time of the power mode are better than those in the economy mode. Fuel consumption of the economy mode is better than that in the power mode. Fuel consumption of PHEV during the CS period is further improved by using the methods proposed in this paper, and this is meaningful for research and development of PHEV.展开更多
Radiation-induced atomic displacement damage is a pressing issue for materials.The present work investigates the number of atomic displacements using the Primary Knock-on Atom (PKA) energy E_(PKA)and threshold displac...Radiation-induced atomic displacement damage is a pressing issue for materials.The present work investigates the number of atomic displacements using the Primary Knock-on Atom (PKA) energy E_(PKA)and threshold displacement energy E_(d)as two major parameters via lowenergy SRIM Binary Collision Approximation (BCA) full cascade simulations.It is found that the number of atomic displacements cannot be uniquely determined by E_(PKA)/E_(d )or E_(D) /E_(d)(E_(D) refers to the damage energy) when the energy is comparable with E_(d).The effective energy E_(D,eff)proposed in the present work allows to describing the number of atomic displacements for most presently studied monatomic materials by the unique variable E_(D,eff)/E_(d).Nevertheless,it is noteworthy that the BCA simulation damage energy depends on E_(d),whereas the currently used analytical method is independent of E_(d).A more accurate analytical damage energy function should be determined by including the dependence on E_(d).展开更多
The modified Siemens method is the dominant process for the production of polysilicon,yet it is characterised by high energy consumption.Two models of laboratory-grade Siemens reduction furnace and 12 pairs of rods in...The modified Siemens method is the dominant process for the production of polysilicon,yet it is characterised by high energy consumption.Two models of laboratory-grade Siemens reduction furnace and 12 pairs of rods industrial-grade Siemens chemical vapor deposition(CVD)reduction furnace were established,and the effects of factors such as the diameter of silicon rods,the surface temperature of silicon rods,the air inlet velocity and temperature on the heat transfer process inside the reduction furnace were investigated by numerical simulation.The results show that the convective and radiant heat losses in the furnace increased with the diameter of the silicon rods.Furthermore,the radiant heat loss of the inner and outer rings of silicon rods was inconsistent for the industrial-grade reduction furnace.As the surface temperature of the silicon rods increases,the convective heat loss in the furnace increases,while the radiative heat loss remains relatively constant.When the inlet temperature and inlet velocity increase,the convective heat loss decreases,while the radiant heat loss remains relatively constant.Furthermore,the furnace wall surface emissivity increases,resulting in a significant increase in the amount of radiant heat loss in the furnace.In practice,this can be mitigated by polishing or adding coatings to reduce the furnace wall surface emissivity.展开更多
文摘At present,as China vigorously develops new energy automobiles,the social demand for related talents has increased significantly,so the relevant institutions need to optimize and adjust the talent training mode to help the development of new energy automobiles.This paper summarizes the existing problems of China’s new energy automobile talent training mode,and analyzes the significance of the virtual simulation-based dual-creation talent training mode of new energy automobile and its specific implementation strategies,in order to provide references for the relevant personnel.
文摘VOF (volume of fluid) method has been used to make the numerical simulation of freak wave come true. The comparisons between the numerical results and linear theoretical results corresponding to Eq.(5) have been carried out to show that the numerical results have a better exhibition of nonlinear characteristics. Wavelet analysis method has been adopted to investigate the time-frequency energy spectrum of simulation freak waves and the results reveal strong nonlinear interaction enables energy to be transferred to high harmonics during the progress of its formation. Varying water depth can enhance the nonlinear interaction, making much more energy be transferred to high harmonics and freak waves with higher asymmetry be generated.
基金Supported by the National Key Projects for Fundamental Research and Development of China(2016YFB0600904)
文摘Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste heat.The mineral carbonation of BF slag can not only reduce emissions of solid waste but also realize the in-situ fixation of CO_2 with low energy consumption if integrated with the waste heat utilization.In this study, based on our previous works, Aspen Plus was employed to simulate and optimize the carbonation process and integrate the process energy.The effects of gehlenite extraction, MgSO_4 carbonation,and aluminum ammonium sulfate crystallization were studied systematically.The simulation results demonstrate that 2.57 kg of BF slag can sequester 1 kg of CO_2, requiring 5.34 MJ of energy(3.3 MJ heat and 2.04 MJ electricity), and this energy includes the capture of CO_2 from industrial flue gases.Approximately 60 kg net CO_2 emission reduction could be achieved for the disposal of one ton of BF slag.In addition, the by-product,aluminum ammonium sulfate, is a high value-added product.Preliminary economic analysis indicates that the profit for the whole process is 1127 CNY per ton of BF slag processed.
基金Project supported by Grant-in-Aid for Scientific Research (JSPS KAKENHI for Young Scientists (S), 21676005)
文摘Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recovery ventilator and to investigate the effect of the air supply arrangement. Three types of mixing ventilation are chosen for the analysis of coupling ANSYS/FLUENT (a computational fluid dynamics (CFD) program) with TRNSYS (a building energy simulation (BES) software). The adoption of mutual complementary boundary conditions for CFD and BES provides more accurate and complete information of indoor air distribution and thermal performance in buildings. A typical office-space situated in a middle storey is chosen for the analysis. The office-space is equipped with air-conditioners on the ceiling. A heat recovery ventilation system directly supplies flesh air to the office space. Its thermal performance and indoor air distribution predicted by the coupled method are compared under three types of ventilation system. When the supply and return openings for ventilation are arranged on the ceiling, there is no critical difference between the predictions of the coupled method and BES on the energy consumption of HVAC because PID control is adopted for the supply air temperature of the occupied zone. On the other hand, approximately 21% discrepancy for the heat recovery estimation in the maximum between the simulated results of coupled method and BES-only can be obviously found in the floor air supply ventilation case. The discrepancy emphasizes the necessity of coupling CFD with BES when vertical air temperature gradient exists. Our future target is to estimate the optimum design of heat recovery ventilation system to control CO2 concentration by adjusting flow rate of flesh air.
文摘Non-pillar continuous mining(NPCM) is regarded as a high-efficient, high-level and one-step mining technology, which can be divided into two substopes. Back fill stability status in substope I, which directly influence the loss rate and dilution rate, etc, will determine whether the experimental research is successful or not. By employing energy method of limit analysis and finite element numerical simulation method, the critical backfill height was determined under the prerequisite condition of its stability, which put forward theoretical basis for reasonable and correct selection of backfill’s parameters. The result showed that the first backfill could not keep stable for NPCM, while the other was able to.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11275007,11105057,11175023,and 11275039)the Program for Liaoning Excellent Talents in University,China(Grant No.LJQ2012098)
文摘We benchmark and analyze the error of energy conservation (EC) scheme in particle-in-cell/Monte Carlo (PIC/MC) algorithms by simulating the radio frequency discharge. The plasma heating behaviors and electron distributing functions obtained by one-dimensional (1D) simulation are analyzed. Both explicit and implicit algorithms are checked. The results showed that the EC scheme can eliminated the self-heating with wide grid spacing in both cases with a small reduction of the accuracies. In typical parameters, the EC implicit scheme has higher precision than EC explicit scheme. Some "numerical cooling" behaviors are observed and analyzed. Some other errors are also analyzed. The analysis showed that the EC implicit scheme can be used to qualitative estimation of some discharge problems with much less computational resource cost without much loss of accuracies.
文摘Based on the characteristic of high energy milling and the micromechanics of composite material, a plastic constitutive equation is implemented for milled composite powders. To check the equation, the extrusion of Ti/Al composite powders prepared by high energy milling was simulated. It was from the numerical analysis that the predicted extrusion pressure mounted up with milling time and extrusion ratio increasing, which was perfect agreement with experimental results.
基金Supported by the National Environmental Protection Bureau of P.R.China(Huan-Ke-Ke,1997,No.006,Project 14),China-Japan cooperative project:"Research on energy savings and alleviating environmental burden in petroleum enterprises"of Institute of Industrial
文摘Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upon which a series of comparative studies on energy savings with conventional distillation columns are carried out. Furthermore, we present an optimization model of ideal ITCDIC, which can be used to achieve the maximum energy saving and find the optimal design parameters directly. The binary system of benzene-toluene is adopted for the illustrative example of simulation and optimization. The results show that the maximum energy saving of ITCDIC is 52.25% (compared with energy consumption of conventional distillation under the minimum reflux ratio operation); the optimal design parameters are obtained, where the rectifying section pressure and the feed thermal condition are Pr=0.3006 MPa and q=0.5107 respectively.
基金financially supported by the National Natural Science Foundation of China(Grant Number 51475465)the Hunan Provincial Innovation Foundation for Postgraduate(Grant Number CX2015B014).
文摘Small moving vehicles represent an important category of marine engineering tools and devices(equipment)typically used for ocean resource detection and maintenance of marine rights and interests.The lack of efficient power supply modes is one of the technical bottlenecks restricting the effective utilisation of this type of equipment.In this work,the performance characteristics of a new type of elastic-blade/wave-energy converter(EBWEC)and its core energy conversion component(named wave energy absorber)are comprehensively studied.In particular,computational fluid dynamics(CFD)simulations and experiments have been used to analyze the hydrodynamics and performance characteristics of the EBWEC.The pressure cloud diagrams relating to the surface of the elastic blade were obtained through two-way fluid-solid coupling simulations.The influence of blade thickness and relative speed on the performance characteristics of EBWEC was analyzed accordingly.A prototype of the EBWEC and its bucket test platform were also developed.The power characteristics of the EBWEC were analyzed and studied by using the blade thickness and motion cycle as control variables.The present research shows that the EBWEC can effectively overcome the performance disadvantages related to the transmission shaft torque load and power curve fluctuations of rigid blade wave energy converters(RBWEC).
基金Shanghai Municipal Science & Technology Projects, China (No. 09DZ1203300, No. 10JC1415200)
文摘The production and energy coupling system is used to mainly present energy flow, material flow, information flow, and their coupling interaction. Through the modeling and simulation of this system, the performance of energy flow can be analyzed and optimized in the process industry. In order to study this system, the component based hybrid Petri net methodology (CpnHPN) is proposed, synthesizing a number of extended Petri net methods and using the concept of energy place, material place, and information place. Through the interface place in CpnHPN, the component based encapsulation is established, which enables the production and energy coupling system to be built, analyzed, and optimized on the multi-level framework. Considering the block and brief simulation for hybrid system, the CpnHPN model is simulated with Simulink/Stateflow. To illustrate the use of the proposed methodology, the application of CpnHPN in the energy optimization of chlorine balance system is provided.
基金supported by the National Natural Science Foundation of China(No.12102256).
文摘Graphene aerogel(GA),as a novel solid material,has shown great potential in engineering applications due to its unique mechanical properties.In this study,the mechanical performance of GA under high-velocity projectile impacts is thoroughly investigated using full-atomic molecular dynamics(MD)simulations.The study results show that the porous structure and density are key factors determining the mechanical response of GA under impact loading.Specifically,the impact-induced penetration of the projectile leads to the collapse of the pore structure,causing stretching and subsequent rupture of covalent bonds in graphene sheets.Moreover,the effects of temperature on the mechanical performance of GA have been proven to be minimal,thereby highlighting the mechanical stability of GA over a wide range of temperatures.Finally,the energy absorption density(EAD)and energy absorption efficiency(EAE)metrics are adopted to assess the energy absorption capacity of GA during projectile penetration.The research findings of this work demonstrate the significant potential of GA for energy absorption applications.
基金the National Key Research and De-velopment Program of China(Grant No.2021YFB3502600)Shenzhen Science and Technology Program(Grant No.JCYJ20220530161813029).
文摘The effect of undercooling DT and the interface energy anisotropy parameter e4 on the shape of the equiaxed dendritic tip has been investigated by using a quantitative phase-field model for solidification of binary alloys.It was found that the tip radius r increases and the tip shape amplitude coefficient A4 decreases with the increase of the fitting range for all cases.The dendrite tip shape selection parameter sdecreases and then stabilizes with the increase of the fitting range,and sincreases with the increase of e4.The relationship between sand e4 follows a power-law function sµea 4,and a is independent of DT but dependent on the fitting range.Numerical results demonstrate that the predicted sis consistent with the curve of microscopic solvability theory(MST)for e4<0.02,and sobtained from our phase-field simulations is sensitive to the undercooling when e4 is fixed.
基金Project supported by the National Key Research Development Program of China(Grant No.2016YFB0701204)the National Natural Science Foundation of China(Grant Nos.U1302272 and 51571055)
文摘A phase-field model is modified to investigate the grain growth and texture evolution in AZ31 magnesium alloy during stressing at elevated temperatures. The order parameters are defined to represent a physical variable of grain orientation in terms of three angles in spatial coordinates so that the grain volume of different order parameters can be used to indicate the texture of the alloy. The stiffness tensors for different grains are different because of elastic anisotropy of the magnesium lattice. The tensor is defined by transforming the standard stiffness tensor according to the angle between the (0001) plane of a grain and the direction of applied stress. Therefore, different grains contribute to different amounts of work under applied stress. The simulation results are well-explained by using the limited experimental data available, and the texture results are in good agreement with the experimental observations. The simulation results reveal that the applied stress strongly influences AZ31 alloy grain growth and that the grain-growth rate increases with the applied stress increasing, particularly when the stress is less than 400 MPa. A parameter (△d) is introduced to characterize the degree of grain-size variation due to abnormal grain growth; the △d increases with applied stress increasing and becomes considerably large only when the stress is greater than 800 MPa. Moreover, the applied stress also results in an intensive texture of the 〈0001〉 axis parallel to the direction of compressive stress in AZ31 alloy after growing at elevated temperatures, only when the applied stress is greater than 500 MPa.
基金funded in part by the Advanced Research Projects AgencyEnergy (ARPA-E), U.S. Department of Energy, under award number DE-AR0001471。
文摘Although train modeling research is vast, most available simulation tools are confined to city-or trip-scale analysis, primarily offering micro-level simulations of network segments. This paper addresses this void by developing the Ne Train Sim simulator for heavy long-haul freight trains on a network of multiple intersecting tracks. The main objective of this simulator is to enable a comprehensive analysis of energy consumption and the associated carbon footprint for the entire train system. Four case studies were conducted to demonstrate the simulator's performance. The first case study validates the model by comparing Ne Train Sim output to empirical trajectory data. The results demonstrate that the simulated trajectory is precise enough to estimate the train energy consumption and carbon dioxide emissions. The second application demonstrates the train-following model considering six trains following each other. The results showcase the model ability to maintain safefollowing distances between successive trains. The next study highlights the simulator's ability to resolve train conflicts for different scenarios. Finally, the suitability of the Ne Train Sim for modeling realistic railroad networks is verified through the modeling of the entire US network and comparing alternative powertrains on the fleet energy consumption.
文摘Renewable energies are of major interest due to their inexhaustible and clean nature, with minimal impact on the environment. Numerous technological pathways exist in this field, each distinguished by the materials used and their implementation principles. However, the cost-efficiency ratio remains a significant challenge for researchers. Currently, organic materials are gaining popularity due to their relatively low cost. However, their performance, particularly in terms of conversion efficiency, still requires improvements. This study focuses on optimizing the organic photovoltaic cell ITO/MoO3/CARAPA/PCBM/Alq3/Al using SCAPS. Several parameters were considered, such as layer thickness, recombination center density, and doping, to improve the cell’s performance. The optimal parameters obtained include an efficiency of 3%, a fill factor of 81.67%, an open-circuit voltage of 1610 mV, and a short-circuit current of 2.28 mA/cm2. The study also revealed that doping the phenyl-C61-butyric acid methyl ester (PCBM) layer has a significant impact on efficiency and short-circuit current, improving these parameters up to a certain point before causing degradation due to increased recombination. Furthermore, high doping of the tri (8-hydroxyquinoline) aluminum (Alq3) layer improves performance up to a critical threshold, after which degradation is also observed. In contrast, doping the molybdenum trioxide (MoO3) layer does not have a notable impact on cell performance. Regarding the thickness of the active Carapaprocera (CARAPA) and PCBM layers, non-optimal values lead to a decrease in performance. Similarly, an optimal thickness of the Alq3 layer significantly improves efficiency. These results highlight the importance of parameter optimization to maximize the efficiency of organic solar cells.
文摘Due to the variable output of renewable energy (RE) generation, difficulties of dispatching RE for power system operators could not be avoided. One of possible solutions is the energy storage technology, especially the battery storage system. The large-scale energy storage system is available to support power system reliable flexibility for load following and system frequency regulation. In this paper, the bottlenecks of large-scale solar power generation dispatching and operation in Qinghai grid are discussed, and a new PV-energy storage coordinated dispatching method is proposed for reduction of PV curtailment in Qinghai. Moreover, the validation based on the time-series production simulation is provided using real data from Qinghai. The results indicate that the proposed method can effectively decrease the curtailment of solar power and future vision of large-scale solar power coordinated operation with energy storage system is also presented.
文摘In this paper, a plug-in hybrid electrical vehicle(PHEV) is taken as the research object, and its dynamic performance and economic performance are taken as the research goals. Battery charge-sustaining(CS) period is divided into power mode and economy mode. Energy management strategy designing methods of power mode and economy mode are proposed. Maximum velocity, acceleration performance and fuel consumption are simulated during the CS period in the AVL CRUISE simulation environment. The simulation results indicate that the maximum velocity and acceleration time of the power mode are better than those in the economy mode. Fuel consumption of the economy mode is better than that in the power mode. Fuel consumption of PHEV during the CS period is further improved by using the methods proposed in this paper, and this is meaningful for research and development of PHEV.
基金supported by the Fundamental Research Funds for the Central Universities,Sun Yat-sen University (No. 2021qntd12)。
文摘Radiation-induced atomic displacement damage is a pressing issue for materials.The present work investigates the number of atomic displacements using the Primary Knock-on Atom (PKA) energy E_(PKA)and threshold displacement energy E_(d)as two major parameters via lowenergy SRIM Binary Collision Approximation (BCA) full cascade simulations.It is found that the number of atomic displacements cannot be uniquely determined by E_(PKA)/E_(d )or E_(D) /E_(d)(E_(D) refers to the damage energy) when the energy is comparable with E_(d).The effective energy E_(D,eff)proposed in the present work allows to describing the number of atomic displacements for most presently studied monatomic materials by the unique variable E_(D,eff)/E_(d).Nevertheless,it is noteworthy that the BCA simulation damage energy depends on E_(d),whereas the currently used analytical method is independent of E_(d).A more accurate analytical damage energy function should be determined by including the dependence on E_(d).
基金funded by the Natural Science Foundation Projects in Sichuan Province(No.2022NSFSC0254).
文摘The modified Siemens method is the dominant process for the production of polysilicon,yet it is characterised by high energy consumption.Two models of laboratory-grade Siemens reduction furnace and 12 pairs of rods industrial-grade Siemens chemical vapor deposition(CVD)reduction furnace were established,and the effects of factors such as the diameter of silicon rods,the surface temperature of silicon rods,the air inlet velocity and temperature on the heat transfer process inside the reduction furnace were investigated by numerical simulation.The results show that the convective and radiant heat losses in the furnace increased with the diameter of the silicon rods.Furthermore,the radiant heat loss of the inner and outer rings of silicon rods was inconsistent for the industrial-grade reduction furnace.As the surface temperature of the silicon rods increases,the convective heat loss in the furnace increases,while the radiative heat loss remains relatively constant.When the inlet temperature and inlet velocity increase,the convective heat loss decreases,while the radiant heat loss remains relatively constant.Furthermore,the furnace wall surface emissivity increases,resulting in a significant increase in the amount of radiant heat loss in the furnace.In practice,this can be mitigated by polishing or adding coatings to reduce the furnace wall surface emissivity.