空间核能布雷顿循环系统热力学参数分析及优化

Thermodynamic Parameter Analysis and Optimization of the Space Nuclear Brayton Cycle System

在深空探索快速发展的背景下,空间核能布雷顿循环系统因其能量密度高、环境适应性强、效率高等优势成为深空探测的理想方案之一。与地面发电站不同的是,空间能量转换系统要兼顾系统效率和轻量化的要求,而系统关键参数对系统的效率和质量等性能有着重要的影响。因此,开展热力学参数分析和优化对空间核能布雷顿循环系统的设计具有重要意义。通过建立空间核能布雷顿循环的数学模型和系统部件的质量计算模型,以“质量比功率”为性能优化目标,研究压气机进口温度、压气机压比和涡轮进口温度等参数对系统性能的影响,并采用正交实验法进行优化分析。结果表明,压气机进口温度和压气机压比存在最优值使质量比功率取得最小值,涡轮进口温度升高有利于提高系统的发电效率和降低系统质量。涡轮进口温度的最优值为1500 K,压气机进口温度的最优值范围为416~508 K,压气机压比的最优值范围为2.4~3.1。

In the context of the rapid development of deep space exploration,the space nuclear Brayton system has become one of the sought-after schemes for deep space exploration because of its high energy density,strong environmental adaptability and high efficiency.The space power conversion system should reconcile the system efficiency and lightweight,which is different from the terrestrial power station,and the key parameters of the system have an important influence on the efficiency and quality.Therefore,the analysis and optimization of thermodynamic parameters are of great significance to the design of the space nuclear Brayton cycle system.The mathematical model of the space Brayton cycle and the calculation methods of the component quality were established in this paper.The influence of compressor inlet temperature,compressor pressure ratio,and turbine inlet temperature on the system performance was investigated with specific mass as the performance optimization objective,and the orthogonal experimental method was adopted for the optimization analysis.The results showed that:optimal values existed for both compressor inlet temperature and compressor pressure ratio to minimize the specific mass;the increase of turbine inlet temperature was conducive to simultaneously improving the electrical efficiency of the system and reducing the system quality.The optimal value of turbine inlet temperature was 1500 K;the optimal value range of the compressor inlet temperature was 416-508 K;the optimal value range of the compressor pressure ratio was 2.4-3.1.