超导核聚变氦低温系统氦透平膨胀机性能分析与匹配控制

Due to the large cooling capacity and high reliability, helium cryogenic turboexpander is considered the most important device for large helium cryogenic systems. Taking into account the basic and common issues of a helium turboexpander employed by a superconducting nuclear fusion helium cryogenic system, experimental and theoretical studies are performed on the flow characteristics and expansion performance. The energy conversion process, the matching performance between the dynamic process and thermal process in the turboexpander are investigated. Through the analysis on the characteristics of cryogenic helium turbine near the Mach number in the rotating distortions channel, sets up a mathematical model of helium cryogenic turbine mainstream and tip clearance flow, revealing the boundary layer sliding and gas-solid (leaf) interface characteristics and interaction principle. Based on the coupling analysis of high speed turbine aerodynamic performance and thermal performance, study of the impact condition of turbine, unsteady flow and cooling down and energy conversion characteristics. Through the study on the matching performance of turbine expansion and brake characteristics, establish the control strategy of cryogenic system of helium expansion turbine. Then establish the performance prediction and match control model of the cryogenic turbine. Based on the predicted energy conversion performance and the dynamic characteristics of helium cryogenic turbine, set up the high efficient turbine operation control strategy. Via the cryogenic helium turbine full working condition experiment, validate and improve the theoretical model. This research is expected to provide effective solutions for the domestic development of the periodicity impact on helium turbine (for the AC loss of superconducting Tokamak device). And the research results may help in the construction of large scale scientific project.

低温氦透平膨胀机是大型氦低温系统运行的关键装置,也是其冷量和性能的保障。针对超导核聚变氦低温系统用氦透平膨胀机的基础和共性问题，拟对低温氦透平膨胀机的流动膨胀及降温特性、能量转换与匹配机理开展理论和实验研究。通过对近马赫数低温氦气在旋转扭曲流道内的膨胀特性分析，建立膨胀机主流和间隙流动的数理模型，揭示边界层滑移以及气-固（叶片）界面特性和相互作用机理；进而基于高速透平气动性能与热力性能的耦合分析，研究冲击工况下膨胀机流道内非稳态流动与降温与能量转换特性；并进行制动风机与膨胀机匹配性能的耦合研究，建立低温系统氦透平膨胀机高效运行控制策略；在此基础上，通过低温氦透平膨胀机全工况实验，验证和改进理论模型，最终实现对氦低温透平的冷量输出与动力学特性进行预测。本项目研究有望为超导核聚变氦低温系统周期性冲击工况下深低温区氦透平膨胀机研制的关键技术提供解决思路，进而为保障大科学工程的建设奠定基础。

低温氦透平膨胀机是大型氦低温系统运行的关键装置,也是其冷量和性能的保障，然而用于超导核聚变装置的氦透平膨胀机不同于通用型氦透平膨胀机，需要在氦透平膨胀机的抗干扰机械性能，变工况热力性能方面开展专门的研究，进行特殊的研究。针对超导核聚变氦低温系统用氦透平膨胀机的基础和共性问题，拟对低温氦透平膨胀机的流动膨胀及降温特性、能量转换与匹配机理开展理论和实验研究。进而基于高速透平气动性能与热力性能的耦合分析，研究冲击工况下膨胀机流道内非稳态流动与降温与能量转换特性；并进行制动风机与膨胀机匹配性能的耦合研究，建立低温系统氦透平膨胀机高效运行控制策略，与最优转速控制策略的模型建立；同时开展了电涡流制动技术与电机制动技术在超导核聚变低温系统氦透平膨胀机上应用的研究，并开发了样机。在此基础上，通过低温氦透平膨胀机全工况实验，验证和改进理论模型，最终实现对氦低温透平的冷量输出与动力学特性进行预测，采用流线曲率发对氦透平膨胀机叶轮进行研究，并建立模型。提出了改善超导核聚变低温系统末级氦透平膨胀机运行稳定的不同方式，有利提升超导核聚变低温系统氦透平膨胀机性能（稳定性与热力学性能），解决其运行稳定性，改善运行效率及抗干扰性能等问题。目前本项目已在国内外核心期刊等发表研究论文12篇，CEC会议论文2篇，ICEC会议论文2篇，全国气体润滑与密封会议论文1篇；申请发明专利1项，实用新型专利申请1项；正在培养博士研究生1名，已经毕业硕士研究生2名。