水力机械主轴密封磁性流体与水体界面波动机理研究

本项目根据水力机械装备瓶颈技术-密封不可靠问题，结合水力机械主密封装置上游进口复杂水流激振力及流动特性，在密封装置中引入磁流体，针对密封磁流体与水流界面层耐压较低的现象，采用疏水性纳米磁流体研制、磁流体-水体双流体模型理论分析、多物理场数值模拟、模型可视化试验的研究方法，对水力机械主轴磁流体密封界面波动机理进行研究，获取不同边界条件下磁流体密封耐压阈值，进一步开展水力机械磁流体密封可视化试验研究，捕捉双流体界面层形态与演变，揭示密封装置流体界面层水流激振力与磁场中磁流体磁力相互作用的物理过程，提出水力机械主轴磁流体密封关键控制参数。在此基础上开展磁流体密封间隙动力学理论研究，分析磁流体间隙运动规律和动力学特性，为水力机械磁流体密封装置设计方法提供理论支撑。

According to the problem of sealing unreliability, which is the bottleneck technology of hydraulic machinery, magneto fluid is introduced into the sealing device in terms of the complex flow exciting force and flow characteristics of hydraulic machinery main sealing device at the upstream inlet. In view of the phenomenon of low pressure resistance between sealing magneto fluid and water flow interface layer, the study on the mechanism of the interface fluctuation of the magneto fluid sealing for the main shaft of hydraulic machinery is undertaken with the means of development of hydrophobic nanometer magneto fluid, theoretical analysis of magneto fluid-water two-fluid model, numerical simulation of multi-physical field and model visualization test. Thus, the pressure threshold of magneto fluid sealing under different boundary conditions is obtained and the visual experimental study on hydraulic mechanical magneto fluid sealing is carried out further. Moreover, the physical process of the interaction between the flow exciting force in the fluid interface layer of the sealing device and the magnetic force of the magneto fluid in the magnetic field is revealed, and the key control parameters of the magneto fluid sealing of the main shaft of the hydraulic machinery are proposed. On this basis, the study on the dynamics theory of the magneto fluid sealing clearance is conducted, and the movement law and dynamic characteristics of the magneto fluid clearance is analyzed, which provides theoretical support for the design method of hydraulic mechanical magneto fluid sealing device.