Research on dynamic coupling characteristics of magnetic fluid and gas medium interface in sealing devices

The widths and shapes of sealing interfaces are key indicators for characterizing the sealing stability of dynamic and static magnetic fluid seals. In this study, the interface of a magnetic fluid seal was numerically simulated and changes in the interfacial shape and width were tested and verified using a magnetic fluid seal device. The results showed that the pressure resistance decreased with an increase in seal clearance, and the magnetic fluid seal interface generated a small leakage channel. Following the complete formation of the leakage channel, the static seal gradually failed. During failure, the interface width of the magnetic fluid became narrow. At a certain pressure, the maximum pressure resistance decreased as a function of the rotational speed. Compared with a static seal, more small leakage channels and bubbles were generated. In constant conditions, such as fixed sealing clearance speed during dynamic and static sealing, the change in the width of the magnetic fluid interface of the dynamic seal was 5–7 times that of the static seal.