基于向心透平效率预测的超临界二氧化碳循环的热力学分析

Thermodynamic Analysis of Supercritical Carbon Dioxide Brayton Cycle Based on the Prediction of the Radial Inflow Turbine Efficiency

透平是超临界二氧化碳(S-CO2)布雷顿循环的核心部件之一。通常,小流量的循环常采用向心透平。透平的效率和循环的设计参数密切相关。在关于S-CO2循环的研究中,透平效率通常设置为定值。目前并没有关于采用透平效率预测对于S-CO2循环,性能影响的研究。本篇文章提出了采用一维向心透平效率的S-CO2循环再压缩循环模型。并在不同的循环参数下,对采用一维透平效率和固定透平效率的S-CO2循环的热力学性能进行对比。结果显示当循环参数改变时,可以采用合适的固定透平效率。然而,当热源流量变化时,探究变工况情况下的透平效率相当重要。

Turbine is one of the core components of the supercritical carbon dioxide(S-CO2)cycle.Generally,the radial inflow turbine is adopted for the small mass flow rate cases.The turbine efficiency is closely related to the cycle design parameters.The turbine efficiency is usually set as a constant value in S-CO2 cycle studies.According to our survey,there are few researches about the influence of the turbine efficiency prediction on the S-CO2 cycle performances.In this paper,the S-CO2 recompression cycle model based on the one dimensional(1 D)radial inflow turbine is proposed.Under different cycle parameters,the comparison of S-CO2 cycle thermodynamic performances based on 1D and constant turbine efficiency is conducted.The results reveal that the proper constant turbine efficiency can be applied when cycle parameters vary.However,it’s important to investigate the off-design turbine efficiency when the heat source mass flow rate changes.