基于金属燃料的SOFC/氦氙布雷顿双闭式循环联合动力系统优化设计

Optimization for Design of SOFC and Helium Xenon Brayton Double-Closed Cycle Combined Power System Based on Metal Fuel

为提高无空气推进闭式动力装置的热效率和续航能力,建立了一种基于金属铝水反应的固体氧化物燃料电池(SOFC)/氦氙布雷顿双闭式循环联合动力系统。首先建立了该系统的数学模型,将系统输出功率设计为100kW,对系统主要参数进行了敏感性分析,分析结果表明:影响系统工况性能的主要参数包括SOFC的工作温度、工作压力和布雷顿循环压气机压比;在固定系统输出量级的情况下,提高SOFC的工作温度与压力增加了其工作效率和功率分担比,对SOFC的增益影响大于对布雷顿循环的增益;压气机压比的变化影响了布雷顿循环的功率分担比,对SOFC效率也呈现先升高后下降的影响趋势,总体看来,压气机压比对布雷顿循环功率分担比的提高存在一个峰值。采用遗传算法对该系统的工作参数进行优化设计,优化设计后,系统总效率较原型设计提高了2.53%,(火用)效率较原型设计提高了2.55%,有效提升了系统的热效率。

To improve the thermal efficiency and duration of an air-independent propulsion power system, a double-closed cycle combined power system is proposed, which is based on the aluminum–water reaction and consists of a closed helium-xenon Brayton cycle and a closed solid oxide fuel cell(SOFC) system. A mathematical model of the system is established, and the output power is fixed at 100 kW. By analyzing the sensitivity influence of the main parameters of the system, it is found that the working temperature and pressure of the SOFC and the compressor pressure ratio of the Brayton cycle have a certain promotion effect on the output power of the system. The research found that increasing the working temperature and pressure of the SOFC increases the thermal efficiency and power sharing ratio of the SOFC system, and also influences the same parameters of the Brayton system. The research also found that increasing the pressure ratio increases the power sharing ratio of the Brayton cycle, increases the thermal efficiency of the SOFC system first and then decreases it, and the thermal efficiency peaks through variations in the compressor ratio.After optimization of the genetic algorithm, the thermal efficiency of the double-closed cycle combined power system is 2.53% higher than that of the prototype design, and the exergy efficiency is 2.55% higher than that of the prototype design. The thermal efficiency of the system is effectively improved.