| With the development of space exploration mission and nuclear reactor technology,space devices with chemical energy and solar energy as electric energy can not meet the requirements of space exploration mission.Compared with chemical power and solar power,the power of space nuclear power can be greatly improved,and the reliability of the device is higher.The thermoelectric conversion part of nuclear power supply can be divided into static conversion and dynamic conversion according to whether there are dynamic components or not.Nuclear power propulsion can greatly reduce the use of propellants,with less structural mass,longer life,and less vibration to spacecraft,with higher control accuracy.In this paper,the space nuclear power system based on thermionic conversion is discussed.The research contents are divided into three parts: space nuclear power supply based on thermionic conversion,thermal emission system and nuclear power propulsion system.In the part of space nuclear power source of thermionic thermoelectric conversion,the mathematical model of thermionic thermoelectric conversion is established.On the basis of satisfying the actual operation condition of space reactor,the thermodynamic calculation of the system is carried out to provide theoretical basis for performance analysis and optimization.The model of thermionic energy converter and the coupling conversion model of thermionic and temperature difference are established to analyze and optimize its performance.It is concluded that when the temperature of emitter is 2000 K,the temperature of receiver is 950 K and the area of electrode is 660cm2,the performance of the system is the best,the output power is 1970 w and the efficiency is 21%;when the temperature of coupling emitter is 2000 K,the temperature of receiver is 1100 K and the temperature of cold end is 700 k,the output power and efficiency of the system are the highest.The output power is 2443 W and the efficiency is 27.4%.In the part of the heat emission system,the waste heat generated by the radiator is directly discharged to the external space through the way of heat radiation,and the radiator occupies a very important part of the quality in the whole system.In this paper,a new structure of heat pipe radiator is designed,its mathematical and physical model is analyzed,and the radiator is simulated and optimized.The influence of different parameters on the performance of radiator is analyzed when the designed electric power is 100 k W and 1MW respectively.It is concluded that when the design power is 100 k W,the inlet temperature of the radiator is 950 K,and the inlet flow rate is 1.3m/s,the area and mass of the radiator are the minimum.When the design electric power is 1MW,the inlet temperature of the radiator is 950 K,and the inlet flow rate is 1.3m/s,the area and mass of the radiator are the smallest,and the influence of the radiator material on the quality is more obvious.In the electric propulsion part,different hall propulsion systems are designed for the electric energy input of 1MW electric power and 100 k W electric power.The mathematical model of high-power Hall thruster is established.The dry weight of hall propulsion system is 468 kg under 100 k W electric power and 1619 kg under 1MW electric power.The effects of propellant mass flow rate on the specific impulse,thrust and the time needed to reach a certain velocity increment are studied.This paper analyzes the hall propulsion system working in two modes,analyzes the influence of different parameters in different modes on the spacecraft flight time and gain speed increment,and points out the direction for optimization. |
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