Single Metal Seal Deformation Analysis And Structural Optimization

With the increasing reduction of conventional oil and natural gas resources,exploration and development is turning to deep strata,deserts and plateaus,the difficulty of drilling and exploitation is increasing,which puts forward higher requirements for the performance of downhole drilling tools.As a rotary seal,single metal seal is commonly used in underground power tools,with the advantages of simple structure,small occupied space,strong shock and impact resistance and so on,which can adapt to high temperature and pressure,complex geological conditions and other conditions.However,under the condition of bad working condition,the sealing ring is subjected to the action of force and thermal load,sealing failure is inevitable,and one of the main reasons for the failure of the seal is the distortion of the seal face.Therefore,it is of great significance to improve the sealing performance of the single metal by carrying out research on single metal sealing force,thermal and thermal mechanical coupling deformation,calculating the flow field performance parameters of the seal surface under the condition of deformation,and optimizing the structure of the seal parameters.Then,the main contents of this paper are as follows:(1)Based on the structural characteristics of single metal seal,the sealing structure and mechanism were studied.At the same time,the parameters which affect the sealing performance were analyzed.(2)Based on the finite element analysis software ANSYS,the pressure field distribution of the single metal seal was calculated,the effects of working parameters,material parameters and structural parameters on the mechanical deformation of single metal seal were studied.(3)The thermodynamic analysis model of single metal seal was established,and the effects of material parameters and operating parameters on the thermal deformation and thermal mechanical coupling deformation of single metal seal ring were studied,and the three kinds of deformation were compared and analyzed as well.(4)The fluid control equation of liquid film with single metal seal under the condition of force deformation was established.The formula of pressure distribution,leakage and opening force of radial liquid film was obtained,and the calculation of the sealing performance was completed by MATLAB software,which laid the foundation for the structure optimization.(5)The single metal sealing structure was optimized based on response surface methodology,through the orthogonal test,the contact width of the end face,the height of the static ring and the inclination of the inclined plane were determined as the design variables,and the deformation taper and leakage were taken as the optimization target,on this foundation,the response surface model was established by the experimental design method of Box-Behnken,and the influence of the interaction between the structural parameters on the performance of the sealing ring was obtained.The response surface model was verified by F test,coefficient of variation,complex correlation coefficient and residual normal probability distribution.(6)Through the penalty function method,the two regression model was optimized,and the optimal structure parameters were obtained,by comparing the performance of single metal seal before and after optimization,the results shown that the sealing performance of single metal was improved effectively.The seal leakage reduced by 35.98%,and the end face deformation taper reduced by 19.9%,the maximum contact pressure of the end face was decreased by 11.369%,the inner contact pressure was decreased by 30.902%and the lateral contact pressure was increased by 61.304%,the contact pressure distribution was more uniform,the maximum temperature of the end face was reduced by 5.424? as well.It was proved that the penalty fiunction optimization method was feasible in the optimization of single metal seal leakage and deformation taper.