Design And Experimental Study Of Shaft End Seal Of Deep Water Reducer

The use environment of marine deep water drill is harsh.In the deep water high pressure environment,the deceleration transmission device often makes the sea water seep into the inner reducer from the gap between the transmission shaft and the end cover because of the seal failure at the end of the shaft,which leads to the increase of the failure rate and greatly reduces the service life.Taking the roller movable gear reducer used in deep water drilling as the research object,the static and dynamic sealing performance of the mechanical seal under high pressure in deep water was studied by analyzing the leakage of the mechanical seal at the shaft end.According to the static seal with the actual installation of O-ring,based on the nonlinear theory of rubber material,applying the finite element method to establish the static seal with a two-dimensional axisymmetric model of O-ring,starting the deep-water environment O-ring seal performance research,by means of numerical simulation of the O-ring contact width,Von Mises stress and the maximum contact stress varies with depth,compression ratio and the changing rule of the rubber hardness,combining with the working condition of marine deep water,determine the static seal with compression ratio and the rubber hardness of the O-ring.The surface texture technique is used to improve the dynamic sealing performance of friction pair between mechanical seal faces.A square-elliptical composite textured seal face is proposed.Establishing composite texture seal face model,applying Fluent simulation software to solve the fluid dynamic pressure lubrication equation,by means of numerical simulation of square,oval,and complex texture film pressure distribution between the seal faces,contrasting and analyzing different rotation speed,sealing medium pressure and seal clearance three shape texture change rule of opening force,liquid film stiffness and leakage rate seal performance parameters.In order to further improve the complex texture sealing performance of the seal face,based on uniform diameter side texture seal face,designing three different arrangement ways of composite texture seals: intersection diameter side texture seal face,inside diameter side texture seal face,outside diameter side texture seal face,based on the finite volume method,contrasting and analyzing four kinds of configuration way under the same conditions texture area ratio between the seal face,composite ratio and texture depth and other structure parameters influence on sealing performance.In order to verify the sealing performance of the composite texture mechanical seal structure,a deep water high pressure simulation test device is designed and built according to the size of the reducer,and the pressure test of the pressure vessel part is carried out.Laser marking machine is used to texture the static ring contact surface of the seal,and the variation law of the static and dynamic sealing properties of the composite texture mechanical seal under different rotating speeds and pressures was investigated.Through the above research work,the problem of high failure rate caused by seal failure at shaft end of roller movable tooth reducer for deep water is effectively improved,and the design of mechanical seal at shaft end of roller movable tooth reducer for deep water is provided for reference.