关键词: 微型阀, CFD, 流固耦合, 瞬态流场特性, 灵敏度分析

Abstract:

Aviation miniature plug-in relief valves in aircraft hydraulic systems have a micro channel structure. Its mechanism of inducing transport characteristics of internal fluid as well as that inducing two-phase flow remains unclear， and the influence of characteristic parameters on product features is not yet well-defined. Therefore， there is an urgent need to develop relevant simulation models for analysis and perform experimental tests. Here， we conduct simulation and experimental studies on an aviation plug-in relief valve in the aircraft hydraulic systems. In the simulation calculation， the influence of the global structural changes and the migration of partial boundary conditions of the valve caused by the spool motion process were considered. Based on the fluid-structure coupling technology， a CFD computational domain division coupling technology was proposed specifically for the complex flow passage structure of the relief valve researched in this paper， which was used to establish a numerical calculation model for the valve global domain. Based on the full cavitation model， turbulence model and spool dynamics calculation model， this computational model can accurately simulate transient characteristics throughout the entire operating cycle， providing insights into the dynamic evolution law of distribution of pressure field， velocity field， cavitation characteristics， and the dynamic variation of spool kinetic characteristics with spool action. To ensure the simulation accuracy， we built the performance test device. Further， a surrogate model for the input output mapping relationship of the valve CFD model was constructed， significantly improving the computational efficiency of the original model. Applying it to large sample model evaluation， we conducted the global sensitivity analysis of the opening and closing as well as the flow characteristic parameters to the input parameters. Results show that the opening and closing process of the researched valve are continuous， rapid， and stable， which can effectively ensure system security. The simulation results of the pressure-flow rate are in good agreement with the experimental data， and the maximum error throughout the entire cycle remains within 5%. Furthermore， the spring characteristics and maximum displacement have a significant impact on the opening and closing characteristics of the valve， requiring particular attention on the design and manufacturing processes of this component. This study contributes to a deeper understanding of the intricate flow mechanisms within the miniature plug-in relief valve， providing theoretical guidance for the development process and holding significant value in enhancing the operational reliability and stability of the hydraulic control system in which the relief valve is employed.

Key words: micro-valve, CFD, flow-structure coupling, transient flow field characteristics, sensitivity analysis