应用于大型氦低温系统的气动低温调节阀动力学特性研究

大型氦低温制冷设备是前沿科技研究、航空航天、高技术应用等不可替代的基础支撑装备。气动低温调节阀作为低温系统控制回路中最重要的执行机构，其动力学特性直接关系到控制过程的稳定性、快速性和准确性。针对现有动力学特性研究中，往往忽略了气动系统的影响，更没有建立一个实用高效的本征模型，无法用于指导气动低温调节阀动力学性能的设计优化。本研究基于网络理论，针对三种不同的激励源，建立了气动低温调节阀气动—机械耦合系统的动力学特性模型。引入阻尼比匹配的调节机制，设计优化气动低温调节阀动力学特性。在此基础上，模拟仿真气动低温调节阀动态响应特性对低温系统压力、流量、温度以及透平膨胀机转速稳定性的影响，并将动力学特性理论应用于2kW@20K低温系统，验证模型的可靠性和实用性。本研究提供了一套气动低温调节阀动力学特性设计优化方法，有利于提升我国气动低温调节阀产品质量和竞争力，为实现大型氦低温制冷设备的国产化奠定基础

The large helium cryogenic refrigeration is the basic support equipment of the frontier science and technology research, aerospace and high technology industries. The dynamic characteristics of the pneumatic cryogenic control valve as the most important actuators of cryogenic control loop directly relate to the stability, rapidity and accuracy of cryogenic system. According to the current research of dynamic characteristics, the effect of pneumatic system is neglected and the practical and efficient model is not created. So it cannot be used to guide the design and optimization of pneumatic cryogenic control valve’s dynamic characteristics. Based on the network theory，dynamic model of pneumatic cryogenic control valve is solved. The stability equation and dynamic response characteristics equation are established according to the three different excitation sources. The design and optimization method are also established by introducing the damping ration matching. Based on those results, the effect on stability of system pressure, flow rate, temperature and turbo-expander speed is investigated using CFD. The reliability and practicability of model are verified with measurement results in the 2kw@20K cryogenic system. This study provides a set of design and optimization method of the pneumatic cryogenic control valve and it will help to improve the quality and competitiveness of pneumatic cryogenic control valve and lay the foundations for the localization of the large helium cryogenic refrigeration.