Study On End Face Structure And Sealing Characteristics Of Dry Gas Seal With Combination Groove

In order to improve the sealing performance of non-contact mechanical seals,taking the seal face of the compressor dry gas seal as the research object,this paper proposes a new type of combined groove seal face,which is composed of two grooves with different groove depths,radial lengths and partially overlapping in the circumferential direction.By establishing it's geometric model and mathematical model,based on the Reynolds equation,the related formula and parameters are solved by the finite difference method;the corresponding calculation program is compiled by MATLAB software,and the numerical calculation of the model is performed to obtain the relationship between changes in end face structure and changes in sealing performance.Besides,it is compared the sealing performance with traditional groove.Based on this,the relevant rules of the sealing performance of combination groove were obtained.The analysis reveals these laws and sealing mechanism,which provides theory and reference for the design and research of the sealed end face.The specific conclusions drawn from this paper are:1)Compared with the traditional grooves,the combination groove has a greater optimization effect on the sealing performance of the end face.In the condition of large film thickness,the combination groove has weak effect on the sealing performance;in the case of small film thickness,the results show that the pressure distribution at the end face of the combination groove is more reasonable,and the opening force and stiffness are improved greatly.The combination grooves has a slight increase in leakage compared to conventional grooves,but overall,the leakage is small.The SLR ratio of the combination grooves is somewhat better than that of conventional grooves.2)The radial ratio of the combination groove about short groove to the long groove has a great influence on the opening force,leakage amount,stiffness and stiffness-to-leakage(SLR)ratio.Among them,the opening force and stiffness is the largest when the radial ratio that the short groove to the long groove is 0.7.The amount of leakage increases with the radial ratio,and the leakage ratio increases fastest when the radial ratio is about 0.5.The ratio of SLR decreases with the increase of the radial ratio.3)The circumferential ratio of the short and long grooves of the combination groove has a smaller influence on the opening force,leakage amount,stiffness and SLR ratio.Among them,the opening force and stiffness fluctuate with the increase of the circumferential ratio.When the circumferential ratio is At 1.0,opening force and stiffness reached the maximum,but the increase range was about 3.0% and 5.7% respectively.The leakage amount increases slightly with the increase of the circumferential ratio,and the SLR ratio decreases slightly with the increase of the circumferential ratio.4)The change of the groove depth of the short and long grooves of the combination groove has a relatively complicated influence on the opening force,leakage,stiffness and the SLR ratio.In general,the change in the groove depth of the long groove has a great influence on the relevant parameters,and the influence of the short groove's is small relatively.However,in the case of small film thickness(film thickness less than 3?m),both of them have considerable influence on the sealing parameters of seal face.