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Sealing Performance of Pressure-Adaptive Seal

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Journal of Shanghai Jiaotong university(Science) 2022年第6期27卷 747-756页

作者：李元丰王怡灵张万欣刘冀念马加炉 National Key Laboratory of Human Factors Engineering China Astronaut Research and Training CenterBeijing 100094China

A pressure-adaptive seal is developed to meet the demands of quick assembling and disassembling for an individual protection equipment in *** analysis model,which reflects the main characteristics of the seal structure,is built based on the finite element method and the Roth’s theory of rubber seal,and verified by the prototype *** influences of precompression ratio,hardness of the sealing ring rubber,and friction coefficient on the sealing performance are investigated by variable parameter *** show that the model can describe the essential characteristics of the pressure-adaptive seal structure,which has good follow-up to the cavity pressure to achieve the purpose of pressure *** leakage rate correlates negatively with the precompression ratio of the sealing ring and the hardness of the sealing ring material,while is positively related to the friction coefficient between the sealing ring and the sealing *** maximum contact stress on sealing surface has negative correlation with the precompression ratio of the sealing ring,and positive correlation with the hardness of the seal ring *** damage risk of the sealing ring increases with the increases of the precompression ratio of sealing ring,hardness of sealing ring material,and friction coefficient.

关键词： pressure-adaptive seal contact stress leakage rate

leakage and Stiffness Characteristics of Bionic Cluster Spiral Groove Dry Gas Seal

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 148-158页

作者： Jin-Bo Jiang Xu-Dong Peng Ji-Yun Li Yuan Chen Engineering Research Center of Process Equipment and Its Re-manufacturing of Ministry of Education Zhejiang University of Technology

Spiral groove dry gas seal(S?DGS), the most widely used DGS in the world, encounters the problem of high leakage rate and inferior film stability when used in high?speed machinery equipment, which could not be well solved by optimization of geometrical parameters and molded line of spiral groove. A new type of bionic cluster spiral groove DGS(CS?DGS) is proved to have superior film stability than S?DGS at the condition of high?speed and low?pressure numerically. A bionic CS?DGS is experimentally investigated and compared with common S?DGS in order to provide evidence for theoretical study. The film thickness and leakage rate of both bionic spiral groove and common spiral groove DGS are measured and compared with each other and with theoretical values under different closing force at the condition of static pressure, high?speed and low?pressure, and the film stiffness and stiffness?leakage ratio of these two face seals are derived by the relationship between closing force and film thickness at the steady state. Experimental results agree well with the theory that the leakage and stiffness of bionic CS?DGS are superior to that of common S?DGS under the condition of high?speed and low?pressure, with the decreasing amplitude of 20% to 40% and the growth amplitude of 20%, respectively. The opening performance and stiffness characteristics of bionic CS?DGS are inferior to that of common S?DGS when rotation speed equals to 0 r/min. The proposed research provides a new method to measure the axis film stiffness of DGS, and validates the superior performance of bionic CS?DGS at the condition of high?speed and low?pressure experimentally.

关键词： Bionic cluster spiral groove Film stiffness Dry gas seal leakage rate

leakage Prediction Method for Contacting Mechanical Seals with Parallel Faces

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Chinese Journal of Mechanical Engineering 2010年第1期23卷 7-15页

作者： SUN Jianjun WEI Long FENG Xiu GU Boqin College of Mechanical and Electronic Engineering Nanjing Forestry UniversitY Nanjing 21003 7 China Department of Engineering Mechanics Southeast University Nanjing 210096 China Fluid Sealing Technique Development Center Nanjing College of Chemical Technology Nanjing 210048 China College of Mechanical and Power Engineering Nanjing University of Technology Nanjing 210009 China

Since the beginning of the 20th century, many researches on the sealing characteristic of mechanical seals were carried out broadly and in depth by various methods and some leakage models were built. But due to the lack of the way to characterize the main factors of influence on the leakage, most of the early researches were based on the assumptions that the seal faces topography and the frictional conditions were invariant. In the early built models, the effect of the surface topography change of the seal face on the leakage rate was neglected. Based on the fractal theory, the contact of end faces of the rotary and stationary rings was simplified to be the contact of a rough surface and an ideal rigid smooth surface, and the contact interface＇s cavity size-distribution function as well as the fractal characteristic of the cavity profile curve was discussed. By analyzing the influence of abrasion on the seal face topography and the leakage channel, the time-correlation leakage prediction model of mechanical seals based on the fractal theory was established and the method for predicting the leakage rate of mechanical seals with parallel plane was proposed. The values of the leakage rate predicted theoretically are similar to the measured values of the leakage rate in the model test and in situ test. The experimental results indicate that the leakage rate of mechanical seals is a transient value. The surface topography of the end faces of the seal tings and its change during the frictional wear of mechanical seals can be accurately characterized by the fractal parameters. Under the work conditions of changeless frictional mechanism, the fractal parameters measured or calculated based on the accelerated testing equation can be used to predict the leakage rate of mechanical seal in service. The proposed research provides the basis for determining the leakage state and predicting working life of mechanical seal.

关键词： mechanical seal leakage rate fractal theory frictional wear accelerated test model

Determination of the 5d6p 3F4-5d2 3F transition probabilities of Ba I

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Frontiers of physics 2012年第2期7卷 235-238页

作者：仲嘉琪余庚华王谨詹明生 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan China Center for Cold Atom Physics Chinese Academy of Sciences Wuhan China Graduate University of the Chinese Academy of Sciences Beijing China

Whether the transitions between 6s5d 3D and 5d6p 3F can be used for laser cooling of barium heavily depends upon the transition probabilities of 5d6p 3F-5d2 3F. Taking the transition 6s5d 3D3-5d6p 3F4 as a scale, the leakage rate of 5d6p 3Fa-5d2 3F was used to evaluate the transition probabilities. 706 nm laser pulses with different durations were applied to a barium atomic beam for 6s5d 3D3-5d2 3F4 optical pumping, and the remaining percentages in 6s5d 3D3 were measured. After exponential fitting, the transition probability of 5d6p 3F4-5d2 3F3,4 was determined to be 2.1（4） ~ 104 s-1, which is in agreement with theoretical calculations using the scaled Thomas-Fermi-Dirac method.

关键词： laser cooling leakage rate transition probability scaled Thomas-Fermi-Dirac method

INVESTIGATION INTO EFFECT OF SPRING PRESSURE ON PERFORMANCE OF BALANCED MECHANICAL SEALS

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Chinese Journal of Mechanical Engineering 2007年第3期20卷 39-43页

作者： SUN Jianjun GU Boqin College of Mechanical and Power Engineenng Nanjing University of Technology Nanjing 210009 China

The loads acting on the sealing elements of balanced mechanical seals are analyzed. When the balance factor approaches the back pressure factor, the spring pressure will become main part of the face pressure. The leakage model of balanced mechanical seals is established on the base of M-B model for rough surface. Several GY-70 type balanced mechanical seals are tested. The influences of the spring pressure both on the leakage rate and on the friction characteristic of balanced mechanical seals are investigated. The research results indicate that as spring pressure increases, both the clear-ance between two end faces and the leakage rate will decrease, and the friction will be more serious because lubrication medium between the rotating ring and the stationary ring reduces, though the increase of the spring pressure may not be enough to change the face friction state of mechanical seals. There exists an optimum spring pressure for mechanical seal operation. Under this spring pres-sure, not only leakage rate is small, but also the seal end surfaces have a fine friction characteristic. Under different operating conditions, identical type mechanical seals may possess different spring pressure. Appropriate selection of spring pressure is valuable to realize long-period and small leakage rate operating of balanced mechanical seals.

关键词： Balanced mechanical seal Spring pressure leakage rate Friction characteristic Fractal geometry

Gas sealing performance test analysis of non-API casing connection with radial cone sealing structure

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Gas sealing performance test analysis of non-API casing conn...