面向节能增效的热流固耦合作用下簧片阀动态特性建模、求解方法研究

The bad dynamic characteristics of the reed valve will not only shorten the valve life, but also decrease the compressor volumetric displacement and increase power consumption. Research on the dynamic characteristics of the reed valve can be served as an important basis for the diagnosis of valve failure and design optimization of valve. Since the valve leaf movement is the result of the coupling effect of fluid field, structure field and temperature field, this project proposes the research on the modeling method for dynamic characteristics under thermal-fluid-structure coupling effect oriented to energy saving and efficiency increasing, carries out a thorough and systematic study on modeling and solution of the reed valve's dynamic characteristics under the multi-filed coupling effect, analysis technology for the reed valve fluid-structure coupling and fluid-thermal coupling based on mode superposition, and energy-saving and efficiency-increasing technology for the reed valve oriented to the volumetric efficiency. By extending the internal pressure situation of the compressor cylinder from the assumed uniform distribution to the real non-uniform distribution in the entire three-dimensional fluid field, taking into account the heat exchange in the cylinder, suction cavity and discharge cavity, the modeling accuracy of the reed valve dynamics can be improved. By improving the existing pseudo-elasticity method to fit the large deformation of the three-dimensional fluid field computational mesh, combined with the three-dimensional fluid-structure interaction analysis based on the multi-stage mode superposition, the calculation accuracy of reed valve's dynamic characteristics can be improved. On this basis, a research on energy saving and efficiency increasing to improve the volumetric efficiency and optimize the dynamic characteristics will be carried out, and will provide a theoretical basis and technical support for the optimized design of the structural parameters of the reed valve.

簧片阀动态特性差不仅会使气阀寿命缩短，还会导致压缩机输气量下降、能耗增加，研究簧片阀动态特性是诊断气阀故障和设计优化气阀的重要依据。簧片阀阀片的运动是在流场、结构场和温度场耦合作用下产生的，针对此特点，本项目提出面向节能增效的热流固耦合作用下动态特性建模方法研究，深入地研究多场耦合作用下的簧片阀动态特性建模与求解、基于振型叠加的簧片阀流固耦合及流热耦合分析技术、面向容积效率的簧片阀节能增效技术。通过将压缩机气缸内部压力均匀分布的假定扩展为现实中压力在整个三维流场的非均匀分布，同时考虑气缸内和吸排气腔内存在的热交换，提高簧片阀动力学建模的准确性。采用并改进现有的伪弹性体法以适应三维流场计算网格的大变形，结合基于多阶振型叠加的三维流固耦合分析，提高簧片阀动态特性的计算精度。在此基础上，开展以提高容积效率和优化动态特性为目标的节能增效技术研究，为簧片阀结构参数的最优化设计提供理论依据和技术支撑。

作为被广泛应用于微型空压机和小型制冷压缩机的一类由柔性自弹阀片组成的气阀，簧片阀的动态特性直接受到流-固、流-热、热-固等多场耦合作用影响，而且影响特性的设计参数之间存在着关联关系。通过研究找出热流固耦合作用下的簧片阀动态特性与气体参数、压缩机参数和气阀结构参数之间的复杂关系并进行准确而快速的建模和求解，这对于完善气阀设计理论、提升我国气阀研究的技术水平而言意义重大。.针对阀片运动与流场、温度场的相互作用机制，首先对簧片阀热流固耦合的三维瞬态数值仿真方法进行了研究，通过分别建立结构域与流体域的三维计算模型以及热交换关系模型，基于不同物理场数据的双向传递与交替求解，得到了整个三维流场的压力非均匀分布情况以及气缸内和吸排气腔内的热交换情况，提高了簧片阀动态特性建模与求解的准确性。通过对压缩机制冷性能进行测试，结果显示实测值与仿真值基本一致，两者在制冷量上的误差约为2%。在此基础上，针对簧片阀动态特性建模中引入的两个气体流动动态特性系数—流量系数和气流推力系数，提出了基于雷诺数和气阀结构参数的动态特性系数参数化方法，利用不同设计参数下的流动特性仿真试验，构建动态特性系数与相关参数之间关系的定量化描述，提高簧片阀动态特性建模精度。.针对多场耦合作用下的簧片阀动态特性快速求解，提出了基于多阶振型叠加的三维流固耦合分析方法和动态特性弱耦合求解方法，通过将振型叠加法扩展应用到三维空间并将叠加的振型增至2-3阶，基于变量分离实现阀片位移量中形状函数与时间函数各自独立，进而采用弱耦合方式依次求解阀片动力学模型和气体流动模型，在快速求解的同时提高计算精度。同时，针对流场边界随阀片运动而变化的特点，提出了基于弹簧法的网格拉压控制方法和基于分区插值的大变形网格更新控制方法，分别实现了气缸和阀片区域的三维流场网格运动更新，保证了阀片大变形时计算的稳定性和精度。.针对簧片阀的节能增效优化，主要围绕关键结构参数的提取和参数的分组与优化进行了研究，分别提出了小样本均匀采样下的自适应步长Morris改进方法、基于模糊关联分析与求解的参数分组方法、基于模糊非支配解的多目标离散粒子群优化算法，数值仿真的结果表明，改进Morris方法比原始方法在提取显著因子时更加准确、稳定，而参数分组与优化方法能有效处理参数分组过程中不确定信息的转化与传递，实现节能增效设计等驱动目标下的设计参数分组和优化。