The Seal Technology Research Of Deep-Sea Hydraulic Power Unit

The deep-sea hydraulic power unit is an important part of submersible and provide power to it. The deep sea environment has many special characteristics, such as ultra-high pressure, low temperature, and strong corrosion. For the reason high power density ratio that the hydraulic is widely used in deep-sea equipment. Oil leak or seawater intrusion in deep-sea environment would seriously affect the performance of the hydraulic system, and even determines the performance the deep-sea equipment, so the seal problem in deep sea environment is particularly important.In this paper, the rubber O-ring of deep-sea hydraulic power unit is took as the research object. To study the sealing performance of the O-ring in static seal and reciprocating seal under the high pressure environment, the ANSYS software is used. Than analyze the influence of environment pressure of different depth on the stress of O-ring.Firstly, this paper introduce the research status of deep-sea hydraulic power unit, deep-sea sealing technology and the related theory of O-ring seal, ANSYS finite element simulation. Thus provide a theoretical basis for the finite element of O-ring seal under deep-sea environment.Secondly, the compression of the O-ring under deep-sea high pressure environment are analyzed. Then focus on the variation of O-ring stress for static seal at no-load condition, load condition under deep-sea environment, including equivalent stress, shear stress and contact stress. As well as the influence of compression ratio, the seal pressure, material hardness on the seal stress. The result showed that:with the increase of the depth of the dive, the stress of the O-ring is gradually decreased for static seal at no-load state, while the equivalent stress and the shear stress increases, the contact stress is basically unchanged for static seal at load state. In addition, according to the deep-sea special environment, the sealing groove width may be appropriately increased in the design process.Finally, the stress variation of O-ring is analyzed in the process of reciprocating seal under deep-sea environment, including equivalent stress, shear stress, contact stress and friction stress. There will be a certain fluctuation for the stress at the beginning of movement, then tend to be stable. Then the influence of many factors, which include compression ratio, the sealing pressure, material hardness, friction coefficient, on the stress of O-ring is studied for inner and outer trip of reciprocating seal under steady state. Through the analysis:with the increase of submergence depth, the equivalent inner stroke stress decreases, the equivalent external stroke stress increases, the shear process of the whole movement stress increases, the friction stress and contact stress is basically unchanged. The stress of inner higher than that of outer, the O-ring is more likely to destructed in inner trip.