This paper presents a kind of modeling approach to the study of the thermal-hydraulic piston pump which is used in the airplane comprehensively. A set of lumped parameter mathematical models are developed which are ba...This paper presents a kind of modeling approach to the study of the thermal-hydraulic piston pump which is used in the airplane comprehensively. A set of lumped parameter mathematical models are developed which are based on conservation of energy. Heat transfer analysis for the piston pump is also given in the paper in which the heat flow inside the piston pump is described precisely. The theoretical basis and modeling stratagy are applied in a typical thermal-hydraulic circuit containing the piston pump. Simulation results are presented which show a comparison of model/rig performance and the agreement obtained demonstrates the validity of the modeling approach.展开更多
In this paper, according to the temperature and strain distribution obtained by considering the Gaussian pump profile and dependence of physical properties on temperature, we derive an analytical model for refractive ...In this paper, according to the temperature and strain distribution obtained by considering the Gaussian pump profile and dependence of physical properties on temperature, we derive an analytical model for refractive index variations of the diode side-pumped Nd：YAG laser rod. Then we evaluate this model by numerical solution and our maximum relative errors are 5% and 10% for variations caused by thermo–optical and thermo–mechanical effects; respectively. Finally, we present an analytical model for calculating the focal length of the thermal lens and spherical aberration. This model is evaluated by experimental results.展开更多
The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation...The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation, the thermal design of ECU for electronic unit pump （EUP） fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time展开更多
Temperature effect on the spin pump in a single quantum dot(QD) connected to Normal(NM) and/or Ferromagnetic(FM) leads is investigated with the help of master equation method. Results show that the magnitude and the d...Temperature effect on the spin pump in a single quantum dot(QD) connected to Normal(NM) and/or Ferromagnetic(FM) leads is investigated with the help of master equation method. Results show that the magnitude and the direction of the temperature difference between the source(L) and drain(R) leads have great impact on the spin current processes. In practical devices, the thermal bias is quite general and then our results may be useful in quantum information processing and spintronics.展开更多
Excellent vacuum performance ensures a high beam transmission efficiency of the neutral beam injector （NBI）. The vacuum performance is mainly determined by the cryoperformance of the cryopanel of the cryocondensatio...Excellent vacuum performance ensures a high beam transmission efficiency of the neutral beam injector （NBI）. The vacuum performance is mainly determined by the cryoperformance of the cryopanel of the cryocondensation pumps which are the main vacuum pumps of NBI. In order to optimize the cryoperformance, the requirements for the temperature distribution and the heat load of the cryopanel are analysed and the factors that affect the cryopanel＇s temperature distribution are studied. The results indicate that the temperature difference of the cryopanel can be reduced by fabricating the cryopanel with high thermal conductivity material, increasing its thickness and cutting the distance between the two upward cooling pipes. The results may be applied to a cryopanel cooled by forced flow liquid helium.展开更多
对基于布雷顿循环的热泵储电(Brayton-pumped thermal energy storage,B-PTES)技术及其他主流长时储能技术的类型和发展状况进行对比和总结;从参数优化、系统配置、循环工质及储热储冷材料选型、储热/冷单元、运行模式、经济性6个方面对...对基于布雷顿循环的热泵储电(Brayton-pumped thermal energy storage,B-PTES)技术及其他主流长时储能技术的类型和发展状况进行对比和总结;从参数优化、系统配置、循环工质及储热储冷材料选型、储热/冷单元、运行模式、经济性6个方面对B-PTES进行梳理和分析。B-PTES在长时储能技术中更具竞争性,但目前效率仍有待提升。在系统配置方面,可综合考虑经济性、工质特性等因素进行多目标优化;在核心设备方面,可通过解决高温压缩机高温蠕变、低温膨胀机低温冷脆以及换热器的强化换热与流动减阻等问题,进一步提升设备效率;另外,火电、核电及冷热电联供等应用场景耦合突出B-PTES技术布置灵活的优势,进一步凸显其在长时储能技术中的竞争力。展开更多
文摘This paper presents a kind of modeling approach to the study of the thermal-hydraulic piston pump which is used in the airplane comprehensively. A set of lumped parameter mathematical models are developed which are based on conservation of energy. Heat transfer analysis for the piston pump is also given in the paper in which the heat flow inside the piston pump is described precisely. The theoretical basis and modeling stratagy are applied in a typical thermal-hydraulic circuit containing the piston pump. Simulation results are presented which show a comparison of model/rig performance and the agreement obtained demonstrates the validity of the modeling approach.
文摘In this paper, according to the temperature and strain distribution obtained by considering the Gaussian pump profile and dependence of physical properties on temperature, we derive an analytical model for refractive index variations of the diode side-pumped Nd：YAG laser rod. Then we evaluate this model by numerical solution and our maximum relative errors are 5% and 10% for variations caused by thermo–optical and thermo–mechanical effects; respectively. Finally, we present an analytical model for calculating the focal length of the thermal lens and spherical aberration. This model is evaluated by experimental results.
文摘The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation, the thermal design of ECU for electronic unit pump （EUP） fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time
基金Supported by the National Natural Science Foundation of China Project under Grant No.11147010the Natural Science Foundation of Inner Mongolia under Grant No.2012MS0113the Research Program of Higher Education of Inner Mongolia Autonomous Region under Grant No.NJZY12111
文摘Temperature effect on the spin pump in a single quantum dot(QD) connected to Normal(NM) and/or Ferromagnetic(FM) leads is investigated with the help of master equation method. Results show that the magnitude and the direction of the temperature difference between the source(L) and drain(R) leads have great impact on the spin current processes. In practical devices, the thermal bias is quite general and then our results may be useful in quantum information processing and spintronics.
基金National Natural Science Foundation of China(No.10575105)
文摘Excellent vacuum performance ensures a high beam transmission efficiency of the neutral beam injector （NBI）. The vacuum performance is mainly determined by the cryoperformance of the cryopanel of the cryocondensation pumps which are the main vacuum pumps of NBI. In order to optimize the cryoperformance, the requirements for the temperature distribution and the heat load of the cryopanel are analysed and the factors that affect the cryopanel＇s temperature distribution are studied. The results indicate that the temperature difference of the cryopanel can be reduced by fabricating the cryopanel with high thermal conductivity material, increasing its thickness and cutting the distance between the two upward cooling pipes. The results may be applied to a cryopanel cooled by forced flow liquid helium.
文摘对基于布雷顿循环的热泵储电(Brayton-pumped thermal energy storage,B-PTES)技术及其他主流长时储能技术的类型和发展状况进行对比和总结;从参数优化、系统配置、循环工质及储热储冷材料选型、储热/冷单元、运行模式、经济性6个方面对B-PTES进行梳理和分析。B-PTES在长时储能技术中更具竞争性,但目前效率仍有待提升。在系统配置方面,可综合考虑经济性、工质特性等因素进行多目标优化;在核心设备方面,可通过解决高温压缩机高温蠕变、低温膨胀机低温冷脆以及换热器的强化换热与流动减阻等问题,进一步提升设备效率;另外,火电、核电及冷热电联供等应用场景耦合突出B-PTES技术布置灵活的优势,进一步凸显其在长时储能技术中的竞争力。
