To improve the global search ability of particle swarm optimization （PSO）, a multi-population PSO based on pyramid model （PPSO） is presented. Then, it is applied to solve the layout optimization problems against t...To improve the global search ability of particle swarm optimization （PSO）, a multi-population PSO based on pyramid model （PPSO） is presented. Then, it is applied to solve the layout optimization problems against the background of an international commercial communication satellite （INTELSAT-Ⅲ） module. Three improvements are developed, including multi-population search based on pyramid model, adaptive collision avoidance among particles, and mutation of degraded particles. In the numerical examples of the layout design of this simplified satellite module, the performance of PPSO is compared to global version PSO and local version PSO （ring and Neumann PSO）. The results show that PPSO has higher computational accuracy, efficiency and success ratio.展开更多
The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In additio...The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In addition,the Mars entry,descent,and landing(EDL)mission led to specific requirements for the accuracy of the aerodynamic deceleration performance,stability,aerothermal heating,and various complex aerodynamic coupling problems of the entry module.This study analyzes the key and difficult aerodynamic and aerothermodynamic problems related to the Mars EDL process.Then,the study process and results of the design and optimization of the entry module configuration are presented along with the calculations and experiments used to obtain the aerodynamic and aerothermodynamic characteristics in the Martian atmosphere.In addition,the simulation and verification of the low-frequency free oscillation characteristics under a large separation flow are described,and some special aerodynamic coupling problems such as the aeroelastic buffeting response of the trim tab are discussed.Finally,the atmospheric parameters and aerodynamic characteristics obtained from the flight data of the Tianwen-1 entry module are compared with the design data.The data obtained from the aerodynamic design,analysis,and verification of the Tianwen-1 entry module all meet the engineering requirements.In particular,the flight data results for the atmospheric parameters,trim angles of attack,and trim axial forces are within the envelopes of the prediction deviation zones.展开更多
A new module design concept that integrates materials engineering with thermoelectric module optimization is proposed.This concept transforms the gaps between thermoelements and couples into internal space/pores withi...A new module design concept that integrates materials engineering with thermoelectric module optimization is proposed.This concept transforms the gaps between thermoelements and couples into internal space/pores within the elements to eliminate heat loss and thus to enhance module performance.The effect of the internal pore structure on module performance was studied using two effective medium models.The modeling results demonstrated that the power generation of the proposed module design increased by~8%and the efficiency increased>20%compared to those of the traditional module design.The effect of the inclusion of the second solid phase in the composite on module performance was also studied using nine different high-efficiency thermoelectric materials as the inclusions.The modeling results showed that further increase in module performance up to~50%that of the traditional module design can be achieved.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50275019, No.50335040, No.50575031).
文摘To improve the global search ability of particle swarm optimization （PSO）, a multi-population PSO based on pyramid model （PPSO） is presented. Then, it is applied to solve the layout optimization problems against the background of an international commercial communication satellite （INTELSAT-Ⅲ） module. Three improvements are developed, including multi-population search based on pyramid model, adaptive collision avoidance among particles, and mutation of degraded particles. In the numerical examples of the layout design of this simplified satellite module, the performance of PPSO is compared to global version PSO and local version PSO （ring and Neumann PSO）. The results show that PPSO has higher computational accuracy, efficiency and success ratio.
基金This research comes from the Tianwen-1 Mars exploration mission.The authors gratefully acknowledge the contributions of the entire Tianwen-1 design team.
文摘The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In addition,the Mars entry,descent,and landing(EDL)mission led to specific requirements for the accuracy of the aerodynamic deceleration performance,stability,aerothermal heating,and various complex aerodynamic coupling problems of the entry module.This study analyzes the key and difficult aerodynamic and aerothermodynamic problems related to the Mars EDL process.Then,the study process and results of the design and optimization of the entry module configuration are presented along with the calculations and experiments used to obtain the aerodynamic and aerothermodynamic characteristics in the Martian atmosphere.In addition,the simulation and verification of the low-frequency free oscillation characteristics under a large separation flow are described,and some special aerodynamic coupling problems such as the aeroelastic buffeting response of the trim tab are discussed.Finally,the atmospheric parameters and aerodynamic characteristics obtained from the flight data of the Tianwen-1 entry module are compared with the design data.The data obtained from the aerodynamic design,analysis,and verification of the Tianwen-1 entry module all meet the engineering requirements.In particular,the flight data results for the atmospheric parameters,trim angles of attack,and trim axial forces are within the envelopes of the prediction deviation zones.
文摘A new module design concept that integrates materials engineering with thermoelectric module optimization is proposed.This concept transforms the gaps between thermoelements and couples into internal space/pores within the elements to eliminate heat loss and thus to enhance module performance.The effect of the internal pore structure on module performance was studied using two effective medium models.The modeling results demonstrated that the power generation of the proposed module design increased by~8%and the efficiency increased>20%compared to those of the traditional module design.The effect of the inclusion of the second solid phase in the composite on module performance was also studied using nine different high-efficiency thermoelectric materials as the inclusions.The modeling results showed that further increase in module performance up to~50%that of the traditional module design can be achieved.
