Research On The Floating Characteristics Of Water Vapor Floating Ring Sea

Steam is a relatively easy to obtain,safe and environmentally friendly working fluid gas.And the floating ring is a shaft end sealing device with easy installation and relatively stable performance.Therefore,for example,processing equipment such as steam compressors,the steam floating ring sealing devices have been widely used.Among them,the floating characteristics of the floating ring is extremely important for the sealing effect and safety performance of the entire unit.To date,the sealing characteristics of floating rings have been mainly based on ideal gas and steady state,however,there are relatively few studies based on actual gas and floating states.In view of this,this paper first takes the floating ring as the research object,and establishes a three-dimensional physical model of the floating ring with different structures of integral type,segmented type,with throttle orifice and without throttle orifice,besides elaborates the working condition parameters and structural parameters.Moreover the complete axial and radial force analysis of the floating ring of different structures was carried out.And the actual gas state equation of steam was summarized,and take the result of the IAPWS-IF97 calculation formula as the related reference object,choose an expression that is suitable for the optimal subsequent calculation.Based on the gas lubrication theory,the mathematical model of the floating ring was established.And considering the actual steam effect and the throttle orifice static pressure effect,the corresponding correction factors are introduced,and afterwards the Reynolds control equation applicable to the actual steam,the throttle orifice static pressure effect and can be combined according to the actual situation is obtained.The relevant program is written by MATLAB software,and the finite difference method is used to solve the pressure of the solved region,and after that the static characteristic parameters such as the load capacity and the leakage amount of the gas film are further calculated,the floating characteristics of the floating ring were studied under condition of steam working fluid gas.The results showed that:(1)For the integral floating rings,with throttle orifice structure have a smaller opening speed,the inlet pressure and the diameter of the throttle orifice have obvious effects on the opening speed,increasing shaft speed and throttle orifice diameter allow for smaller upward floating eccentricities.(2)For the segmented floating rings,with throttle orifice structure have a smaller opening speed,the inlet pressure has a significant influence on the opening speed,and the influence of the diameter of the throttle orifice is weak,increasing shaft speed and throttle orifice diameter allows for greater upward floating film thickness,when the depth of the dynamic pressure groove is in the extent of 2～3μm,the load capacity of the gas film reaches the maximum,so the dynamic pressure effect is the strongest,the opening speed is the smallest,and the thickness of the upward floating gas film is the largest.(3)For the integral and the segmented floating rings,the inlet pressure and shaft speed have an impact on the static characteristic parameters of the corresponding gas film load capacity and the leakage amount,and form a certain change law.(4)For the integral and the segmented floating rings,within the range of the working conditions and structural parameters covered in this paper,the calculation results of ideal steam and actual steam are relatively close,and the error range is small.