Analysis of mechanical characteristics and normal operating conditions of magnetic seals

Abstract

Aiming at the leakage failure problem caused by the accidental disengagement of the sealing interface due to the failure of the magnetic seal force balance system, taking a certain type of aero-engine magnetic seal as an example, the mechanical analysis model of the magnetic seal is established, and the mechanical conditions for normal sealing work are deduced according to the set of equilibrium equations of force. The analysis process of the normal operation is proposed, and the calculation method of the key mechanical parameters of the magnetic seal is determined. On this basis, the influence of operating conditions on the normal operating mechanical conditions is analyzed. The results show that the primary sealing face contact pressure, the maximum contact pressure of the secondary sealing face, and the traction torque of the rotor determine the normal operating condition of the magnetic seal. Excessive chamber pressure and rotational speed will increase the contact pressure of the primary sealing face, leading to increased wear of the face and slippage between the O-Ring 1 and the shaft; too little differential pressure and rotational speed will lead to the disengagement of the graphite ring/stator, which ultimately leads to the failure of the seal. Severe vibration reduces the contact pressure of the primary sealing face and increases the risk of the primary sealing face disengagement.