Based on analyzing the extreme working conditions

such as high-speed

cryogenic

high-pressure and low viscosity lubricants

a thermo-elastic-hydrodynamic-mechanical multi-field coupling model for the non-contact hydrodynamic mechanical seal in the high-speed turbopump was presented

and the model couple the multi-parts in the seal system

such as seal stator

rotor

sealed fluid and the static supporting elements. The performances of the seal are obtained by solving numerically the coupling model and the main parameters of the seal are optimized. The optimization targets are the maximum of the open force of the seal W and the leakage Q and the minimum of the seal-film generated power (or temperature rise). The seal sample with the optimization parameters is used in the experimental test with the liquid nitrogen as the sealed fluid

and the rapid start-up and friction characteristics of the seal under the cryogenic conditions are obtained. The results show the optimization parameters of the seal with the internal spiral-shaped and external herringbone grooves combination structure are that the groove number is 30 and the groove-depth is 3μm. The friction coefficient of the seal under the cryogenic conditions is 0.14.