Effect Of The Outer Circumferential Surface Texture Of The Seal Ring On The Convective Heat Transfer Effect Of Mechanical Seals

The mechanical seal is the most commonly used form of the shaft end seal of the turbo pump.However,in actual operation,the excessive temperature rise of the end face often leads to the vaporization of the liquid film between the end faces and the thermal deformation of the end face.The destruction of the device attached to the turbo pump is therefore critical to reduce the temperature rise.In this paper,the mechanical seal of the turbo pump is taken as the research object,and the influence of the convection heat transfer effect on the outer surface of the moving ring is processed to achieve the goal of significantly reducing the temperature of the end surface under the premise of low stirring power consumption caused by the surface texture.Provide guidance to improve the design and manufacture of turbo pump mechanical seals.The main research contents and results are as follows:Firstly,based on the principle of fluid mechanics and heat transfer,the three-dimensional axisymmetric model of the seal ring and the seal cavity is established by using the commercial software Fluent to solve the problem of the seal failure of the turbo pump mechanical seal due to the high end surface temperature in actual operation.The continuity equation and energy equation of the fluid between the end faces introduce the friction heat of the end face in the form of UDF.Through the solution of the flow field,temperature field and pressure field,the mechanical seals at low and medium speeds are compared and analyzed.The heat transfer and convective heat transfer effects of two types of structure seal rings on the outer surface of the moving ring,and the optimization of the surface texture structure parameters under certain working conditions.The results show that the temperature of the end face of the textured seal ring is significantly lower than that of the ordinary seal ring.The temperature drop ratio at 1800 rpm is about 11%.The presence of the surface texture causes the fluid to change direction inside the texture and The vortex effect generates turbulence outside the texture and forms a high-pressure differential area.These effects strengthen the convective heat transfer strength of the seal ring and the medium in the seal cavity;the strength of the convective heat transfer effect of the seal ring isdeveloped for surface textures of different shapes.Through comparative analysis,it is found that under the equivalent conditions of surface texture density ratio,triangles among the various surface textures studied have the strongest heat transfer capacity.Secondly,for the equilateral triangle surface texture,the analysis is carried out under the working background of the turbo pump with high speed and small size.Through numerical simulation and simulation analysis,it is found that the triangular texture on the outer surface of the moving ring still has an obvious strong change under high-speed and high-pressure conditions.Thermal capacity,through a single variable method to change the texture structure parameters for optimal analysis,found that the depth of the texture,the circumscribed circle radius and the rotation angle have a greater impact on the heat transfer effect,and the row spacing between the axial textures,adjacent to the seal face The structural parameters such as the distance from the center of the first row of texture to the end surface,the number of texture rows,the rotation angle and the interleaving angle of the adjacent texture are relatively small.When any side of the equilateral triangle seals the end surface vertically and its When the diagonal direction is opposite to the direction of rotation of the seal ring,the convective heat transfer effect is the best,and the speed and pressure are changed.It is found that the heat transfer effect is negatively related to the speed and positively related to the pressure;at the same time,it is encountered in the actual processing of triangular texture The problem has been further optimized.In addition,the ratio of the reduction of the washing power consumption brought by the texture to the increase of the stirring power consumption is defined as the ratio of the heat exchange gain of the texture,and the influence of this ratio on the speed and pressure is analyzed.Finally,in order to verify the reliability of the theoretical analysis results,a high-speed turbo pump mechanical seal simulation test device was designed and built,using 15 # aviation hydraulic oil as the test medium,for two types of mechanical seals,ordinary seal ring and textured seal ring,and The sealing performance and heat transfer performance of mechanical seals with different texture seal rings were compared with each other,and compared with the results of numerical simulation research.The results show that the test results are consistent with the numerical simulation calculation results.The seal has obvious cooling effect at 8000 rpm,and the cooling range is about 6 ℃,which is basically consistent with the theoretical research results.Therefore,the correct numerical simulation model and calculation method were verified,and the research results improved the design method of the mechanical seal of the turbo pump without additional flushing/cooling pipeline.