多级轴流超临界二氧化碳压气机气动性能研究

Investigation on Aerodynamic Performance of a Multistage Axial Compressor for Supercritical Carbon Dioxide Power Cycle

二氧化碳作为动力循环工质可获得更高的循环效率和部件紧凑性,应用前景广阔。基于给定参数设计了1台4级轴流式超临界二氧化碳(SCO2)压气机,通过划分六面体网格,采用有限体积法及SSTk-ω湍流模型对其气动性能进行了详细分析,并对叶顶间隙的影响规律进行了研究。研究表明,由于流动加速和引射作用,叶顶间隙泄漏流造成了叶尖吸力侧流体温度和压力的下降,因此该区域可能会发生冷凝现象,并且叶顶间隙的增大进一步降低了该区域的参数,将会导致级效率和压比的降低。研究成果可为SCO2压气机设计提供参考。

Using supercritical carbon dioxide (SCO2 ) as working fluid of power cycle will bring advantages of high efficiency and compact machinery. A four-stage SCO2 axial compressor is designed based on given design parameters. Aerodynamic analysis of the compressor is then performed adopting hexahedral mesh, finite volume method and SST k-ω two-equation turbulence model. Moreover, the influence of tip clearance is investigated. Due to flow acceleration and ejector effect, tip clearance leakage flow causes a decrease of pressure and temperature in the fluid on the suction side of the tip. Hence, condensation in this area may occur. The increase of tip clearance further decreases the parameters in this region and consequently degrades the stage efficiency and pressure ratio of SCO2 compressor. The results may provide a foundation for further design and investigation of SCO2 compressors.