燃料串/并联的航空SOFC-GT混合系统性能对比分析

Comparative analysis of performance of aviation SOFC-GT hybrid system with fuel series/parallel connection

固体氧化物燃料电池-涡轮(SOFC-GT)混合系统作为电推进飞机的动力源时,会面临低温低压的大气环境以及对重量有严苛的要求,因此通过优化系统构型使得该混合系统满足航空应用是一种有效的解决方式。为此本文提出了燃料并联和串联的两种SOFC-GT混合系统构型,并从热力循环理论、系统热力学性能以及系统功重比等方面依次对其进行了对比分析。结果表明,并联系统的热力学性能要优于串联系统,对于系统发电效率、比功和功重比分别提高3.32%,113.14%和34.04%,CO_(2)排放率降低3.22%。随压比的提升串联系统的效率存在最优点,随燃烧室温度的提升并联系统的效率持续下降。在空燃比为4~6的变化范围内,串联系统的输出功率变化幅度更大,相对并联系统为116.29%~87.11%。除此之外,虽然SOFC-GT混合系统的功重比相对较低,但基于其优异的效率,在系统能量密度方面整体要优于锂电池,这有利于提升电推进飞机的性能。

When the solid oxide fuel cell-gas turbine(SOFC-GT)hybrid system is used as the power source for electric propulsion aircraft,it faces low-temperature and low-pressure atmospheric environment and has strict weight requirements.Therefore,optimizing the system configuration to make the hybrid system satisfy the aviation applications is an effective way to solve the problems.In this paper,two configurations of SOFC-GT hybrid system with fuel in parallel and series are proposed,and they are compared and analysed in terms of ther-mal cycle theory,system thermodynamic performance and power-to-weight ratio.The results show that the ther-modynamic performance of the parallel system is better than that of the series system.The electrical efficiency,specific work and power-to-weight ratio increase by 3.32%,113.14%and 34.04%,respectively,and the CO_(2) emission rate is reduced by 3.22%.With the increase of the pressure ratio,the efficiency of the series system has an optimal value,while with the increase of the combustor temperature,the efficiency of the parallel system con-tinues to decline.In the range of 4~6 of the ratio of air to fuel,the output power of the series system changes more obviously,which is 116.29%~87.11%compared with the parallel system.In addition,although the power-to-weight ratio of the SOFC-GT hybrid system is relatively low,it is better than the lithium battery in terms of ener-gy density based on its excellent efficiency,which is conducive to improving the performance of electric propul-sion aircraft.