A stratospheric airship is an essential flight vehicle in the aviation field.In this paper,optimal design approach of stratospheric airships is developed to optimize envelope shape considering three failure modes and ...A stratospheric airship is an essential flight vehicle in the aviation field.In this paper,optimal design approach of stratospheric airships is developed to optimize envelope shape considering three failure modes and multidisciplinary analysis models,and could also reduce the mass of a stratospheric airship to be deployed at a specific location.Based on a theoretical analysis,three failure modes of airships including bending wrinkling failure,hoop tearing failure and bending kink failure,are given to describe and illustrate the failure mechanism of stratospheric airships.The results show that the location,length and size of the local uniform load and the large fineness ratio are easier to lead to bending wrinkling failure and bending kink failure.The small fineness ratio and the increasing differential pressure are more prone to cause hoop tearing failure for an airship hull.The failure probability is sensitive to the wind field.From an optimization design,the reliability analysis is essential to be carried out based on the safety of the airship.The solution in this study can provide economical design recommendations.展开更多
The purpose of this study is to optimize the mass of 1.5 MW wind turbine steel tower performing Genetic Algorithm method (GA). In accordance with ASCE 7-98, AISC-89 and IEC61400-1 , the impact of loads on tower is cal...The purpose of this study is to optimize the mass of 1.5 MW wind turbine steel tower performing Genetic Algorithm method (GA). In accordance with ASCE 7-98, AISC-89 and IEC61400-1 , the impact of loads on tower is calculated within the highest safety conditions against buckling strength of each sections of tower by means of GA codes. The stifness along tower is ensured entirely while the mass of tower is mitigated and optimized.展开更多
Sampling ports were firstly drilled on a ZGM95 coal mill in the power plant in China, and the coal samples from various points in the pulverizer were collected under the different operation conditions. The prop- erty ...Sampling ports were firstly drilled on a ZGM95 coal mill in the power plant in China, and the coal samples from various points in the pulverizer were collected under the different operation conditions. The prop- erty of the sampling material from the mill was analyzed, applying the float-sink test, size distribution analysis, proximate analysis and so on. It was indicated that the ＋250 I^m fraction in the pulverized fuel accounted for only 0.02%, while it was 83.2% in the new feed. The circulating ratio and coal flow in the separator and the cone zone were calculated using the mass balance of the circulating load. So, the cir- culating ratio in the separator of the pulverizer was between 8 and 13, and the circulating ratio, the feed flow of separator and cone zone all raised with the increase of the air volume. Furthermore, the parameters of the separation functions were obtained based on the fitting method. It was shown that the mean value of the shape factor B was 0.7617, and the parameter D which is the particle size at 50% cumulative yield in the separator almost kept unchanged.展开更多
VOF method which consists in transporting a discontinuous marker variable is widely used to capture the free surface in computational fluid dynamics.There is numerical dissipation in simulations involving the transpor...VOF method which consists in transporting a discontinuous marker variable is widely used to capture the free surface in computational fluid dynamics.There is numerical dissipation in simulations involving the transport of the marker.Numerical dissipation makes the free surface lose its physical nature.A free surface sharpening strategy based on optimization method is presented in the paper.The strategy can keep the location of the free surface and local mass conservation at both time,and can also keep free surface in a constant width.It is independent on the types of solvers and meshes.Two famous cases were chosen for verifying the free surface sharpening strategy performance.Results show that the strategy has a very good performance on keeping local mass conservation.The efficiency of prediction of the free surface is improved by applying the strategy.Accurate modeling of flow details such as drops can also be captured by this method.展开更多
Electrocatalytic CO_(2) reduction technology offers an effective way to convert CO_(2) into valuable chemicals and fuels,presenting a sustainable solution for carbon emissions.Current electrocatalytic CO_(2) reduction...Electrocatalytic CO_(2) reduction technology offers an effective way to convert CO_(2) into valuable chemicals and fuels,presenting a sustainable solution for carbon emissions.Current electrocatalytic CO_(2) reduction technologies encoun-ter significant issues such as salt precipitation and hydrogen evolution,which prevent energy conversion efficiency,selectivity,current density,and stability from simultaneously meeting industrial standards.In recent years,research-ers have discovered that increasing the CO_(2) pressure on the gas supply could enhance the coverage of the catalyst and activate more CO_(2) reduction reaction sites on the catalyst surface,which provides a practical and effective approach for optimizing the energy conversion and mass transfer.In this review,we provide a comprehensive review of the development history and current status of high-pressure CO_(2) electrocatalytic reduction technology,focus-ing on its reaction devices,catalytic performance,and reaction mechanisms.Furthermore,we summarize and offer insights into the most promising research avenues to propel the field forward.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.11872160 and 11572099)。
文摘A stratospheric airship is an essential flight vehicle in the aviation field.In this paper,optimal design approach of stratospheric airships is developed to optimize envelope shape considering three failure modes and multidisciplinary analysis models,and could also reduce the mass of a stratospheric airship to be deployed at a specific location.Based on a theoretical analysis,three failure modes of airships including bending wrinkling failure,hoop tearing failure and bending kink failure,are given to describe and illustrate the failure mechanism of stratospheric airships.The results show that the location,length and size of the local uniform load and the large fineness ratio are easier to lead to bending wrinkling failure and bending kink failure.The small fineness ratio and the increasing differential pressure are more prone to cause hoop tearing failure for an airship hull.The failure probability is sensitive to the wind field.From an optimization design,the reliability analysis is essential to be carried out based on the safety of the airship.The solution in this study can provide economical design recommendations.
文摘The purpose of this study is to optimize the mass of 1.5 MW wind turbine steel tower performing Genetic Algorithm method (GA). In accordance with ASCE 7-98, AISC-89 and IEC61400-1 , the impact of loads on tower is calculated within the highest safety conditions against buckling strength of each sections of tower by means of GA codes. The stifness along tower is ensured entirely while the mass of tower is mitigated and optimized.
基金The financial support from the Australian Government as Part of the Asia-Pacific Partnership on Clean Development and Climate,and the National Natural Science Foundation of China (Nos. 51074156 and 51274196)
文摘Sampling ports were firstly drilled on a ZGM95 coal mill in the power plant in China, and the coal samples from various points in the pulverizer were collected under the different operation conditions. The prop- erty of the sampling material from the mill was analyzed, applying the float-sink test, size distribution analysis, proximate analysis and so on. It was indicated that the ＋250 I^m fraction in the pulverized fuel accounted for only 0.02%, while it was 83.2% in the new feed. The circulating ratio and coal flow in the separator and the cone zone were calculated using the mass balance of the circulating load. So, the cir- culating ratio in the separator of the pulverizer was between 8 and 13, and the circulating ratio, the feed flow of separator and cone zone all raised with the increase of the air volume. Furthermore, the parameters of the separation functions were obtained based on the fitting method. It was shown that the mean value of the shape factor B was 0.7617, and the parameter D which is the particle size at 50% cumulative yield in the separator almost kept unchanged.
基金funded by National Natural Science Foundation of China,Grant number:51176012
文摘VOF method which consists in transporting a discontinuous marker variable is widely used to capture the free surface in computational fluid dynamics.There is numerical dissipation in simulations involving the transport of the marker.Numerical dissipation makes the free surface lose its physical nature.A free surface sharpening strategy based on optimization method is presented in the paper.The strategy can keep the location of the free surface and local mass conservation at both time,and can also keep free surface in a constant width.It is independent on the types of solvers and meshes.Two famous cases were chosen for verifying the free surface sharpening strategy performance.Results show that the strategy has a very good performance on keeping local mass conservation.The efficiency of prediction of the free surface is improved by applying the strategy.Accurate modeling of flow details such as drops can also be captured by this method.
基金supported by the Natural Science Basic Research Program of Shaanxi(No.2024JC-YBMS-284)Sichuan Science and Technology Program(No.2024YFHZ0037)the Fundamental Research Funds for the Central Universities.
文摘Electrocatalytic CO_(2) reduction technology offers an effective way to convert CO_(2) into valuable chemicals and fuels,presenting a sustainable solution for carbon emissions.Current electrocatalytic CO_(2) reduction technologies encoun-ter significant issues such as salt precipitation and hydrogen evolution,which prevent energy conversion efficiency,selectivity,current density,and stability from simultaneously meeting industrial standards.In recent years,research-ers have discovered that increasing the CO_(2) pressure on the gas supply could enhance the coverage of the catalyst and activate more CO_(2) reduction reaction sites on the catalyst surface,which provides a practical and effective approach for optimizing the energy conversion and mass transfer.In this review,we provide a comprehensive review of the development history and current status of high-pressure CO_(2) electrocatalytic reduction technology,focus-ing on its reaction devices,catalytic performance,and reaction mechanisms.Furthermore,we summarize and offer insights into the most promising research avenues to propel the field forward.
