Numerical Analysis Of Spiral Groove Liquid Film Seal

Non-contacting fluid lubricated mechanical seal (Fluid Film Seal, also called Upstream Pumping Mechanical Seal) is one of the advanced mechanical seals. Because of the virtues of endurable wear, long service life, low energy consumption, stable operation condition, good adaptability, can achieve zero leakage and zero emission etc., fluid film seal has been applied in petrochemical rotating fluid services such as pumps and compressors. During operation of fluid film seal, it is often out of work owing to the gasification of liquid as a result of high temperature or friction and wear caused by excessive face deformation. So the analysis on the steady-state behavior of spiral groove liquid film seal is necessary.In this paper a theory model considering the face radial coning was presented. The modified Reynolds equation was solved using the finite element program, and the fluid film pressure distribution between the seal faces was obtained. The steady-state performance parameters such as the opening force, the pumpover rate, the steady fluid film stiffness etc. were calculated. The influence of the fluid viscosity, film thickness and radial taper on the seal steady-state behavior was analyzed. Then, according to the energy conservation equation, a formula used for the calculation of the temperature distribution of the seal face was simplified. The temperature distribution of the seal face was computed using the finite element program. The influence of the coupling between liquid viscosity and face temperature to the temperature distribution of the seal face was analyzed. In addition, the radial taper of the deformed seal face was calculated with the moment theory. Finally, the overall coupling relationship between face deformation, fluid viscosity, pressure and temperature distribution was calculated. Considering the coupling relationship, the pressure distribution, temperature distribution and viscosity distribution were obtained, and the influence of speed and groove depth on steady-state behavior was analyzed.The results show that the distribution and gradient of pressure during steady state are influenced significantly by parameters. Thanks to the liquid nature that its viscosity decreases as the temperature increases, the temperature of the seal face is effectively reduced, and the overgreat temperature rise of the seal face is inhibited. The form of the radial distortion of the face seal is convergent, which is in favor of the increase of the hydrodynamic effect. After overall coupling calculation, temperature rise decreases most significantly.