超高压多级向心透平内部复杂流动和耦合机理研究

Multistage radial turbines which can operate efficiently in a wide working range are critical to the development of compressed air energy storage(CAES) system. Based on the integrated experimental platform about the CAES system in the Institute of Engineering Thermophysics, Chinese Academy of Sciences, the project aims to study the sliding pressure operation process to reveal the complex internal flow mechanism, dynamic characteristic and coupling mechanism of the multistage radial turbine of the CAES. The object of this study is a MW-class four-stage radial turbine. Firstly, the flow field of four-stage radial turbine will be measured in detail under the real condition by hot-wire anemometer, micro multipoint 5-hole probe and high-accuracy sensor in the MW-class storage turbine test rig, which can eliminate additional error caused by modeling test. In addition, the four-stage radial turbine is analyzed by computational fluid dynamics (CFD) verified with experimental data. Based on experimental and CFD results, the complex internal flow mechanism of the four-stage radial turbine in the supercritical condition will be studied by topology theory, the coupling mechanism in different stages of the radial turbine and the coupling mechanism of thermal source and radial turbine under the sliding pressure condition will be further analyzed. Finally, it will be proposed the optimization design theory and control strategy for multistage radial turbines under the super-high pressure condition and the wide working range to provide the theoretical guidance for sliding pressure operation of multistage radial turbines. The research will improve the efficiency and economics of CAES system and establish the important foundation for the application of large-scale CAES system.

高效率宽工况多级向心透平对压缩空气储能系统发展至关重要，本项目依托中科院工程热物理所压缩空气储能系统综合实验平台，开展多级向心透平滑压运行研究，揭示其内部流动特性和耦合机理。本研究以MW级超高压四级向心透平为研究对象，采用热线风速仪、微型五孔探针和高精度传感器等对四级向心透平开展全工况实验研究，可消除模化实验带来的额外误差。利用实验数据校验后的数值方法对四级向心透平进行多级耦合CFD模拟，并将实验和CFD模拟结果对比分析，引入拓扑理论，分析超临界进口条件下其内部流动特性和损失机理，揭示滑压运行过程中各级向心透平之间以及向心透平与热源之间的耦合作用机制，探索保持多级向心透平在滑压运行过程中高效稳定运行的调控和优化设计方法，提出宽工况、超高压的多级向心透平优化设计理论与控制策略，为多级向心透平滑压运行提供理论指导，从而提高压缩空气储能系统效率和经济性，为大规模压缩空气储能系统应用奠定重要基础。

本课题依托中国科学院工程热物理研究所超临界压缩空气储能系统综合实验平台，开展多级向心透平滑压运行研究，揭示其内部流动特性、损失机理和耦合机理。主要研究内容及成果为：.(1) 超高压力下向心透平内流动特性和损失机理，完成了MW级多级向心透平气动性能测量实验，包括整机实验和单级部件实验；建立了闭式和半开式向心透平CFD数值求解模型，准确性验证完成，揭示了闭式向心透平和半开式向心透平内部流场结构和损失机理。.(2) 多级向心透平系统的耦合机理，以实验数据为基础搭建了耦合机理研究模型，分析模型内部能量传输机制，通过对不同影响因素的研究，揭示了各级透平、换热器压损、温差以及热源温度等对多级向心透平性能的影响规律。.(3) 滑压运行条件下多级向心透平运行策略，完成多级向心透平整体数值模拟模型搭建，通过额定工况单变量和多变量的影响机制研究，提出滑压运行过程中多变量的控制方法，使得多级向心透平在较宽的工作范围内都保持高效运行，提高系统的经济性。.项目通过以上研究成果，优化了多级向心透平的设计方法，由此推动超临界压缩空气储能系统的产业化与发展，为大规模超临界压缩空气储能系统的应用奠定了重要基础，并为类似的工业向心透平的应用提供借鉴和参考。