蓄热式太阳能热光伏-热推进双模系统设计与性能分析

Design and Performance Analysis of Solar Thermophotovoltaic-Propulsion Bi-Modal System

关键词:  太阳能热推进  蓄热  热光伏  光伏电池  推力系数  比冲

Key words:  Solar thermal propulsion  Thermal energy storage  Thermophotovoltaics  Photovoltaic cell  Thrust coefficient  Specific impulse

摘要:

为有效解决在日蚀区太阳能热推进器推力失效、电力中断的问题，提出了蓄热式太阳能热光伏-热推进双模系统结构，并对系统各部件建立相关物理数学模型，分析了工质种类、工质流量等因素对推进性能的影响。结果表明，为保证推进器在日蚀区30min内持续提供推力和电力供应，砷化镓热光伏电池在无工质工况下能提供10W左右的低功率电力供应，在设计工况下能提供50W～110W的电力供应；液氢作为工质时，最大比冲将达到806s，随着工质流量的持续增加，比冲损失速率呈现先加快后减慢的变化趋势；液氨作为替代工质具有更快的加热速率，其比冲为240s～300s远低于氢工质比冲，其推力系数1.77要略高于氢工质推力系数1.7。通过本文研究，蓄热式太阳能双模推进系统具有较好的可行性，且推力及比冲适中，有望弥补低比冲化学推进和小推力电推进技术的不足。

Abstract:

In order to effectively solve the problem of thrust failure and power interruption of solar thermal propulsion during eclipse, a solar thermophotovoltaic-propulsion bi-modal system with the capability of heat storage was proposed. The mathematical models of the components of system are established. Effects of different types of working fluids and mass flow rates on the propulsion performance are also analyzed. To ensure that the thruster can provide thrust and power supply continuously within 30 minutes of the eclipse, the GaAs thermal photovoltaic cell can provide about 10W power supply under non-working condition, and can provide 50W～110W power supply under design condition. When liquid hydrogen is used as working fluid, the maximum specific impulse will reach 806s. With the flow rate of hydrogen increasing, the rate of specific impulse loss increases and then decreases. Ammonia is heated faster than hydrogen through heating tubes when liquid ammonia is used as working fluid, but its specific impulse (240s~300s) is far lower than that of hydrogen and its thrust coefficient of 1.77 is higher than that of hydrogen which is approximately 1.7. From what have been discussed above, the proposed bi-modal solar propulsion system has good feasibilities, and its moderate thrust and specific impulses are promising to compensate for the performance gap between chemical propulsion (low specific impulse) and electric propulsion (small thrust).