Comparative Study Of High Pressure Liquid Lubricant Mechanical Face Seal With Typical Deep Grooves

Mechanical seal is a key part which is widely used in fluid machinery and power machinery shaft-end seal. Under the condition of high parameter, the traditional contacting mechanical seal is easy to cause the problems, such as serious abrasion of seal faces and short service life, but the hydrodynamic mechanical seal with millimetre-sized deep grooves can improve the lubrication conditions and achieve desirable lubrication effect. So it is widely used in high parameter fluid equipment shaft-end seal, such as nuclear main pumps and boiler feed water pumps. In the engineering applications, different kinds or parameters of grooves have their own characteristics and is not in the best performance for all the working conditions. So the paper is aimed at studying the influence of different types or parameters on the sealing performance by the method of theory combining with experiment.Based on the hydrodynamic lubrication theory, using the MATLAB by finite volume method to solve the Reynolds equation and obtain the pressure distribution of film. Through establishing three-dimensional solid model and using the finite element software on the corresponding boundary conditions and load including film pressure, the function of film thickness and seal performance parameters is obtained. The study found that, under the influence of mechanical deformations,seal face forms circular waviness and radial taper. With the increase of pressure, the friction coefficient gradually decrease and the trend becomes slow. With the increase of revolution speed, film thickness、friction coefficient and liquid film stiffness increases slightly,and the leakage is also increase.By using high pressure sealing test-bed, different kinds or parameters of grooves is designed. Under the different conditions of operation, performance comparison experiment research was studied for mechanical face seal with typical deep grooves. This study is aimed at providing more reliable basis for the practical engineering application of hydrodynamic mechanical seal. This experimental study show that the performance of the three kinds of deep grooves variation trend is consistent, with the increase of pressure, the friction performance is better, which also verify the theory of deep groove mechanical seal is suitable for high pressure conditions. The friction performance of circular grooves is relatively superior, but its leakage rate is relatively large. The shape of the deep groove have bigger influence on the leakage rate The experiment found that leakage rate show a sharp increase in 1MPa,2900r/min. After the test, the wear surface was observed and analyzed by a surface profiler. The study can provide a reliable basis for the actual engineering application of hydrodynamic mechanical seal.