To study the combustion behavior of municipal solid waste(MSW)in blast furnace,the combustion process within the raceway was simulated using computational fluid dynamics.Based on the parameters of an actual blast furn...To study the combustion behavior of municipal solid waste(MSW)in blast furnace,the combustion process within the raceway was simulated using computational fluid dynamics.Based on the parameters of an actual blast furnace,a three-dimensional model including coal lance,blowpipe,tuyere,and raceway was established.The model was then used to compare the combustion characteristics of pulverized coal and MSW in the raceway and to investigate the effects of blast temperature and particle size on the combustion characteristics of MSW in the raceway.The results showed that MSW combusted more rapidly,achieving a maximum temperature of 3839 K in the raceway,comparing to 2974 K during pulverized coal injection.However,the average temperature during MSW injection was 1790 K,which was 73 K lower than that of pulverized coal injection.The maximum velocity during MSW injection was 120 m/s,lower than 188 m/s obtained during pulverized coal injection.MSW could be completely burned out in the middle of the raceway,while the burnout of pulverized coal at this position was only 50%.The combustion effect of MSW makes no difference when the blast temperature increased from 1273 to 1673 K,due to its excellent combustion characteristic.When the MSW particle size was increased from 0.074 to 2 mm,the burnout was 75%,which was still higher than that of pulverized coal injection with a particle size of 0.074 mm.However,injecting larger-sized fuel might increase the risk of tuyere wear.To ensure stable furnace conditions and great combustion,a blast temperature of 1473 K and a MSW particle size of about 1 mm will be better.展开更多
半导体制冷箱的制冷效率是评价制冷箱性能的重要参数,因此提高制冷效率是设计的重点。对制冷装配体与制冷箱的耦合方式进行优化,并运用Solid Works Flow Simulation软件进行仿真分析。对比得出,在制冷装配体风扇外表面与制冷箱内壁重合...半导体制冷箱的制冷效率是评价制冷箱性能的重要参数,因此提高制冷效率是设计的重点。对制冷装配体与制冷箱的耦合方式进行优化,并运用Solid Works Flow Simulation软件进行仿真分析。对比得出,在制冷装配体风扇外表面与制冷箱内壁重合、所开槽尺寸为41.7mm×41.7mm×20mm、风扇为吸气时,制冷箱内温度最低。展开更多
动平台激光通信用稳瞄转台是激光通信的运动执行机构,其中O型架是转台连接光学基台的关键结构,合理化的结构设计和应力分布是保证激光通信功能的稳定的重要因素。使用Solid Works对O型架进行三维建模,并通过Solid Works Simulation对其...动平台激光通信用稳瞄转台是激光通信的运动执行机构,其中O型架是转台连接光学基台的关键结构,合理化的结构设计和应力分布是保证激光通信功能的稳定的重要因素。使用Solid Works对O型架进行三维建模,并通过Solid Works Simulation对其进行有限元分析,得到O型架的应力分布和位移量,在此基础上,通过优化算例进行优化设计,从而达到优化结构、提高激光通信稳定性的目的。展开更多
阐述了运用三维软件Solid Works及其有限元分析插件Solid Works Simulation,建立钣金结构件的仿真模型并进行有限元分析的方法和步骤,分析了安装支架的力学特性,得到了实际工况下应力、位移及应变,确定了合理的设计结构。利用仿真技术,...阐述了运用三维软件Solid Works及其有限元分析插件Solid Works Simulation,建立钣金结构件的仿真模型并进行有限元分析的方法和步骤,分析了安装支架的力学特性,得到了实际工况下应力、位移及应变,确定了合理的设计结构。利用仿真技术,可以提高设计效率,保证设计可靠性。展开更多
连杆蝶阀作为蝶阀的一种结构形式,广泛地应用于各种管道系统。阀板是蝶阀核心构件之一,其结构和材料都是经过严格的设计和选定。由阀板所受的压强全部由立板承受,对其等效处理可得到作用在立板上的力,通过Solid Works软件对立板进行三...连杆蝶阀作为蝶阀的一种结构形式,广泛地应用于各种管道系统。阀板是蝶阀核心构件之一,其结构和材料都是经过严格的设计和选定。由阀板所受的压强全部由立板承受,对其等效处理可得到作用在立板上的力,通过Solid Works软件对立板进行三维造型,并用Solid Works Simulation对其进行有限元分析,得出立板的应力分布和变形量,进而对立板的结构尺寸进行优化,达到节约材料和减小成本的目的。展开更多
Shallow water infrastructure needs to support increased activity on the shores of Semarang.This study chooses several pontoons because of their good stability,rolling motion,and more expansive space.A coupled simulati...Shallow water infrastructure needs to support increased activity on the shores of Semarang.This study chooses several pontoons because of their good stability,rolling motion,and more expansive space.A coupled simulation method consisting of hydrodynamic and structural calculations has been used to evaluate a catamaran pontoon’s motion and structural integrity.Four different space sizes are set for the pontoon system:5 m,5.5 m,6 m,and 6.5 m.The frequency domain shows that the pontoon space affects the RAO in wave periods ranging from 3 s to 5 s.At wave periods of 3 s,4 s,and 5 s,the pontoon space significantly affects the maximum motion and chain tension parameter values,which are evaluated via time domain simulation.The critical stress of the pontoon is shown at a wave period of 5 s for 5 m and 5.5 m of pontoon space,which shows that the stress can reach 248 MPa.展开更多
As energy demand increases,the depth of mining is increasing,and methane disasters grow more serious,efficient extraction of methane is the ultimate method of preventing and controlling methane disasters.The objective...As energy demand increases,the depth of mining is increasing,and methane disasters grow more serious,efficient extraction of methane is the ultimate method of preventing and controlling methane disasters.The objectives for this research are to explore the efficiency of N_(2) injection to enhance gas extraction from coal seams(N_(2)-ECGE)and its impact on coal seam permeability.By developing a fluid-solid coupling model and using COMSOL Multiphysics to perform numerical simulations,the changes in gas pressure,methane content,gas production,output rate and permeability of coal seams were comparatively analyzed under the two methods of direct extraction and N_(2)-ECGE.The research results show that N_(2)-ECGE can significantly improve the coal seam gas pressure and reduce the coal seam CH_(4) content,and the larger the N_(2) injection pressure the more significant the reduction effect.Meanwhile,N_(2)-ECGE can significantly increase the CH_(4) extraction and output rate,and the increase of N_(2) pressure further improves the extraction efficiency.In addition,the pressure of nitrogen injection has a remarkable effect on coal seam permeability,high pressure of nitrogen injection can increase the permeability in the time of no disturbance,but the rate of permeability decreases more quickly after disturbed.The effect of strain due to adsorption desorption on coal seam permeability dominates.Despite model construction limitations,this research offers essential theoretical and practical direction for N_(2) injection to enhance the permeability evolution law of coal seam gas extraction process.展开更多
1.Introduction Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)is a powerful tool for simulating dense gas-solid reacting flows,which is essential in combustion,metallurgy,and waste management.Traditional...1.Introduction Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)is a powerful tool for simulating dense gas-solid reacting flows,which is essential in combustion,metallurgy,and waste management.Traditional methods face challenges in CFD-DEM modeling of dense gas-solid flows due to multi-scale characteristics,limiting resolution and creating simulation bottlenecks.By integrating fluid dynamics and particle behavior,it optimizes industrial processes.This review highlights advancements,applications,and challenges,emphasizing its role in sustainable engineering.展开更多
Single-phase concentrated solid solution alloys(SP-CSAs),including high-entropy alloys,have received extensive attention due to their excellent irradiation resistance.In this work,displacement cascade simulations are ...Single-phase concentrated solid solution alloys(SP-CSAs),including high-entropy alloys,have received extensive attention due to their excellent irradiation resistance.In this work,displacement cascade simulations are conducted using the molecular dynamics method to study the evolution of defects in Ni-based SP-CSAs.Compared with pure Ni,the NiCr,NiCo,and NiCu alloys exhibit a larger number of Frankel pairs(FPs)in the thermal peak stage,but a smaller number of surviving FPs.However,the NiFe alloy displays the opposite phenomenon.To explain these different observations for NiFe and other alloys,the formation energy and migration energy of interstitials/vacancies are calculated.In the NiFe alloy,both the formation energy and migration energy barrier are higher.On the other hand,in NiCr and other alloys,the formation energy of interstitials/vacancies is lower,as is the migration energy barrier of interstitials.The energy analysis agrees well with previous observations.The present work provides new insights into the mechanism behind the irradiation resistance of binary Ni-based SP-CSAs.展开更多
Based on the basic principle of vehicle crash analysis using the finite element method, a car finite element model was built by using Hypermesh software. To simulate the front collision test of the car, the LS-DYNA so...Based on the basic principle of vehicle crash analysis using the finite element method, a car finite element model was built by using Hypermesh software. To simulate the front collision test of the car, the LS-DYNA software is adopted to calculate the deformation of the car and the acceleration time history curves during the crashing process;the anti-impact capability of the car is evaluated from this simulation. The results demonstrate that the improvement of local structure can promote the crashworthiness of the car, but the further improvement needs a major change of the car structure.展开更多
A program on the solidification process of horizontal centrifugal casting coupled with eutectic carbides segregation has been developed in this paper. Due to the geometrical features of work roll, a cylindrical coordi...A program on the solidification process of horizontal centrifugal casting coupled with eutectic carbides segregation has been developed in this paper. Due to the geometrical features of work roll, a cylindrical coordinate system was used. The temperature field of the outer layer at the end of filling process was imported as the initial temperature condition for the solidification process. The model of eutectic carbides segregation caused by different densities between eutectic MC and the molten steel was coupled in the program. The temperature field of the outer layer of work roll during horizontal centrifugal casting process was investigated. Results show that the outer layer has a ＂sandwich shape＂ solid fraction manner. Results also indicate that the segregation of eutectic MC is quite severe during centrifugal casting process. It forms four zones of different content of carbides in radial direction. The simulated results of MC carbides segregation phenomenon agree with the experimental observations.展开更多
Solid adsorption system, one of alternative refrigeration systems, is utilized to provide cold for refrigerator or air-conditioner and can be operated by assistance of solar heat. System performance study through comp...Solid adsorption system, one of alternative refrigeration systems, is utilized to provide cold for refrigerator or air-conditioner and can be operated by assistance of solar heat. System performance study through computer usage to develop simulation program and simulate behaviors of system operation can give designed system which suits for user’s need. Also, the present study aims to develop dynamic simulation program of solid adsorption refrigeration system operated by solar assistance to simulate behaviors of system operation and its performance. Flat plate collectror is utilized to provide thermal energy for system’s adsorber and activated carbon/methanol is used to be a suitable working pair. Simulation procedure starts with various solar radiation intensities as input energy on solar collector and water is used as collector working fluid. Behavior of system operation can be considered to be 4 steps as isosteric heating, isobaric desorption, isosteric cooling and isobaric adsorption, respectively. This research studies the effect of varying solar radiation intensity on temperature, pressure of adsorber, adsorption ratio at each steps of system operated ranging from 6:00 am (the first day) to 6:00 am (the next day) and system performance which is defined as coefficient of performance, COP. In addition, the simulation result shows monthly average COP of 0.43 compared to a result of another previous research work under the same operating condition and the percentage error is 7.5%.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51804024 and 52474342)the Fundamental Research Funds for the Central Universities(No.FRF-IC-20-09)the State Key Laboratory of Advanced Metallurgy of University of Science and Technology Beijing(No.41621002).
文摘To study the combustion behavior of municipal solid waste(MSW)in blast furnace,the combustion process within the raceway was simulated using computational fluid dynamics.Based on the parameters of an actual blast furnace,a three-dimensional model including coal lance,blowpipe,tuyere,and raceway was established.The model was then used to compare the combustion characteristics of pulverized coal and MSW in the raceway and to investigate the effects of blast temperature and particle size on the combustion characteristics of MSW in the raceway.The results showed that MSW combusted more rapidly,achieving a maximum temperature of 3839 K in the raceway,comparing to 2974 K during pulverized coal injection.However,the average temperature during MSW injection was 1790 K,which was 73 K lower than that of pulverized coal injection.The maximum velocity during MSW injection was 120 m/s,lower than 188 m/s obtained during pulverized coal injection.MSW could be completely burned out in the middle of the raceway,while the burnout of pulverized coal at this position was only 50%.The combustion effect of MSW makes no difference when the blast temperature increased from 1273 to 1673 K,due to its excellent combustion characteristic.When the MSW particle size was increased from 0.074 to 2 mm,the burnout was 75%,which was still higher than that of pulverized coal injection with a particle size of 0.074 mm.However,injecting larger-sized fuel might increase the risk of tuyere wear.To ensure stable furnace conditions and great combustion,a blast temperature of 1473 K and a MSW particle size of about 1 mm will be better.
文摘半导体制冷箱的制冷效率是评价制冷箱性能的重要参数,因此提高制冷效率是设计的重点。对制冷装配体与制冷箱的耦合方式进行优化,并运用Solid Works Flow Simulation软件进行仿真分析。对比得出,在制冷装配体风扇外表面与制冷箱内壁重合、所开槽尺寸为41.7mm×41.7mm×20mm、风扇为吸气时,制冷箱内温度最低。
文摘动平台激光通信用稳瞄转台是激光通信的运动执行机构,其中O型架是转台连接光学基台的关键结构,合理化的结构设计和应力分布是保证激光通信功能的稳定的重要因素。使用Solid Works对O型架进行三维建模,并通过Solid Works Simulation对其进行有限元分析,得到O型架的应力分布和位移量,在此基础上,通过优化算例进行优化设计,从而达到优化结构、提高激光通信稳定性的目的。
文摘连杆蝶阀作为蝶阀的一种结构形式,广泛地应用于各种管道系统。阀板是蝶阀核心构件之一,其结构和材料都是经过严格的设计和选定。由阀板所受的压强全部由立板承受,对其等效处理可得到作用在立板上的力,通过Solid Works软件对立板进行三维造型,并用Solid Works Simulation对其进行有限元分析,得出立板的应力分布和变形量,进而对立板的结构尺寸进行优化,达到节约材料和减小成本的目的。
基金financially supported by the Riset Pengembangan dan Penerapan(RPP),Diponegoro University 2023 research scheme with contract number 609-18/UN7.D2/PP/VIII/2023.
文摘Shallow water infrastructure needs to support increased activity on the shores of Semarang.This study chooses several pontoons because of their good stability,rolling motion,and more expansive space.A coupled simulation method consisting of hydrodynamic and structural calculations has been used to evaluate a catamaran pontoon’s motion and structural integrity.Four different space sizes are set for the pontoon system:5 m,5.5 m,6 m,and 6.5 m.The frequency domain shows that the pontoon space affects the RAO in wave periods ranging from 3 s to 5 s.At wave periods of 3 s,4 s,and 5 s,the pontoon space significantly affects the maximum motion and chain tension parameter values,which are evaluated via time domain simulation.The critical stress of the pontoon is shown at a wave period of 5 s for 5 m and 5.5 m of pontoon space,which shows that the stress can reach 248 MPa.
基金supported by the National Natural Science Foundation of China(52374249,52130409,52121003)the National Key R&D Program(2023YFC3009003)+1 种基金the Basic Research Business Fees for Central Universities(2024JCCXAQ01)Open Fund of State Key Laboratory of Coal Mine Disaster Dynamics and Control(2011DA105287-FW202303).
文摘As energy demand increases,the depth of mining is increasing,and methane disasters grow more serious,efficient extraction of methane is the ultimate method of preventing and controlling methane disasters.The objectives for this research are to explore the efficiency of N_(2) injection to enhance gas extraction from coal seams(N_(2)-ECGE)and its impact on coal seam permeability.By developing a fluid-solid coupling model and using COMSOL Multiphysics to perform numerical simulations,the changes in gas pressure,methane content,gas production,output rate and permeability of coal seams were comparatively analyzed under the two methods of direct extraction and N_(2)-ECGE.The research results show that N_(2)-ECGE can significantly improve the coal seam gas pressure and reduce the coal seam CH_(4) content,and the larger the N_(2) injection pressure the more significant the reduction effect.Meanwhile,N_(2)-ECGE can significantly increase the CH_(4) extraction and output rate,and the increase of N_(2) pressure further improves the extraction efficiency.In addition,the pressure of nitrogen injection has a remarkable effect on coal seam permeability,high pressure of nitrogen injection can increase the permeability in the time of no disturbance,but the rate of permeability decreases more quickly after disturbed.The effect of strain due to adsorption desorption on coal seam permeability dominates.Despite model construction limitations,this research offers essential theoretical and practical direction for N_(2) injection to enhance the permeability evolution law of coal seam gas extraction process.
文摘1.Introduction Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)is a powerful tool for simulating dense gas-solid reacting flows,which is essential in combustion,metallurgy,and waste management.Traditional methods face challenges in CFD-DEM modeling of dense gas-solid flows due to multi-scale characteristics,limiting resolution and creating simulation bottlenecks.By integrating fluid dynamics and particle behavior,it optimizes industrial processes.This review highlights advancements,applications,and challenges,emphasizing its role in sustainable engineering.
基金supported by the National Natural Science Foundation of China(12232008,12072211)Foundation of Key laboratory(2022JCJQLB05703)Sichuan Province Science and Technology Project(2023NSFSC0914,2020JDJQ0029).
文摘Single-phase concentrated solid solution alloys(SP-CSAs),including high-entropy alloys,have received extensive attention due to their excellent irradiation resistance.In this work,displacement cascade simulations are conducted using the molecular dynamics method to study the evolution of defects in Ni-based SP-CSAs.Compared with pure Ni,the NiCr,NiCo,and NiCu alloys exhibit a larger number of Frankel pairs(FPs)in the thermal peak stage,but a smaller number of surviving FPs.However,the NiFe alloy displays the opposite phenomenon.To explain these different observations for NiFe and other alloys,the formation energy and migration energy of interstitials/vacancies are calculated.In the NiFe alloy,both the formation energy and migration energy barrier are higher.On the other hand,in NiCr and other alloys,the formation energy of interstitials/vacancies is lower,as is the migration energy barrier of interstitials.The energy analysis agrees well with previous observations.The present work provides new insights into the mechanism behind the irradiation resistance of binary Ni-based SP-CSAs.
文摘Based on the basic principle of vehicle crash analysis using the finite element method, a car finite element model was built by using Hypermesh software. To simulate the front collision test of the car, the LS-DYNA software is adopted to calculate the deformation of the car and the acceleration time history curves during the crashing process;the anti-impact capability of the car is evaluated from this simulation. The results demonstrate that the improvement of local structure can promote the crashworthiness of the car, but the further improvement needs a major change of the car structure.
基金the financial support from CAS/SAFEA International Partnership Program for Creative Research Teams
文摘A program on the solidification process of horizontal centrifugal casting coupled with eutectic carbides segregation has been developed in this paper. Due to the geometrical features of work roll, a cylindrical coordinate system was used. The temperature field of the outer layer at the end of filling process was imported as the initial temperature condition for the solidification process. The model of eutectic carbides segregation caused by different densities between eutectic MC and the molten steel was coupled in the program. The temperature field of the outer layer of work roll during horizontal centrifugal casting process was investigated. Results show that the outer layer has a ＂sandwich shape＂ solid fraction manner. Results also indicate that the segregation of eutectic MC is quite severe during centrifugal casting process. It forms four zones of different content of carbides in radial direction. The simulated results of MC carbides segregation phenomenon agree with the experimental observations.
文摘Solid adsorption system, one of alternative refrigeration systems, is utilized to provide cold for refrigerator or air-conditioner and can be operated by assistance of solar heat. System performance study through computer usage to develop simulation program and simulate behaviors of system operation can give designed system which suits for user’s need. Also, the present study aims to develop dynamic simulation program of solid adsorption refrigeration system operated by solar assistance to simulate behaviors of system operation and its performance. Flat plate collectror is utilized to provide thermal energy for system’s adsorber and activated carbon/methanol is used to be a suitable working pair. Simulation procedure starts with various solar radiation intensities as input energy on solar collector and water is used as collector working fluid. Behavior of system operation can be considered to be 4 steps as isosteric heating, isobaric desorption, isosteric cooling and isobaric adsorption, respectively. This research studies the effect of varying solar radiation intensity on temperature, pressure of adsorber, adsorption ratio at each steps of system operated ranging from 6:00 am (the first day) to 6:00 am (the next day) and system performance which is defined as coefficient of performance, COP. In addition, the simulation result shows monthly average COP of 0.43 compared to a result of another previous research work under the same operating condition and the percentage error is 7.5%.
