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ZHOU Jianfeng
GU Boqin
College of
Mechanical and Power
Engineering,
Nanjing University of Technology,
Nanjing 210009, China
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CHARACTERISTCS OF FLUID FILM
IN OPTIMIZED SPIRAL GROOVE
MECHANICAL SEAL
Abstract:
In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydro- dy-namic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilib-rium condition of the bearing force and the closing force. For different gap dimensions, the relation-ship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.
Key words:
Mechanical seal Pressure distribution Optimal design Bearing force Leakage rate |