Transient dynamic analysis and experimental verification on lubrication regime transition during startup period of non-contacting mechanical seal in liquid oxygen turbopump

The transition process of lubrication regime during startup period of liquid oxygen lubricated seal is investigated. A comprehensive numerical model is proposed, which includes asperity contact, transient micro-clearance flow as well as dynamic motion with axial vibration and angular misalignment. The influence of structural and operational parameters on separation capacity is compared. Meanwhile, the transient response under a strong vibration environment is analyzed. An experimental verification combined with various sensors is designed to monitor film formation. Results show that leakage has obvious oscillation with high-frequency and low-amplitude when face separation. Excessive frequency or amplitude in a vibration environment may cause intermittent contact. Evidently different characteristics of acoustic emission signals are observed corresponding to various lubrication regimes during startup and shutdown.