Seal Structure Research Articles

The burden of diabetes on the soft tissue seal surrounding the dental implants.

Soft tissue seal around implant prostheses is considered the primary barrier against adverse external stimuli and is a critical factor in maintaining dental implants' stability. Soft tissue seal is formed mainly by the adhesion of epithelial tissue and fibrous connective tissue to the transmembrane portion of the implant. Type 2 diabetes mellitus (T2DM) is one of the risk factors for peri-implant inflammation, and peri-implant disease may be triggered by dysfunction of the soft tissue barrier around dental implants. This is increasingly considered a promising target for disease treatment and management. However, many studies have demonstrated that pathogenic bacterial infestation, gingival immune inflammation, overactive matrix metalloproteinases (MMPs), impaired wound healing processes and excessive oxidative stress may trigger poor peri-implant soft tissue sealing, which may be more severe in the T2DM state. This article reviews the structure of peri-implant soft tissue seal, peri-implant disease and treatment, and moderating mechanisms of impaired soft tissue seal around implants due to T2DM to inform the development of treatment strategies for dental implants in patients with dental defects.

Numerical and experimental study of convergent integral embedded magnetic fluid seal

To enhance the pressure resistance of small clearance magnetic fluid seals, a new convergent integral embedded magnetic fluid seal (CIEMFS) structure was proposed. The magnetic field distributions in the radial sealing clearance and axial sealing clearance were studied, and the theoretical pressure resistance capability values were obtained. The effects of magnetic fluid injection volumes, pole tooth (PT) heights and sealing clearance on the pressure resistance capability of the CIEMFS were experimentally investigated and compared with that of the ordinary magnetic fluid seal (OMFS). The results showed that the experimental pressure resistance capability of the CIEMFS was in good agreement with the theoretical pressure resistance, and both of them were better than the OMFS. The pressure resistance capability of the CIEMFS is not only affected by the radial sealing clearance but also limited by the axial seal clearance. The height of the pole tooth and the magnetic fluid (MF) injection volume will also have an impact on the pressure resistance capability, the higher the pole tooth, the higher the pressure resistance capability of the magnetic fluid sealing (MFS) structure. As the magnetic fluid injection volume increases, the pressure resistance capability of the CIEMFS increases and then plateaus.

Experimental study on the critical pressure of divergent stepped magnetic fluid seal with a small clearance and single magnetic source

Herein, a divergent stepped magnetic fluid seal with a single magnetic source is designed to improve the pressure capability of ordinary magnetic fluid seal under small clearance. To explore the effects of injection volume, axial clearance, radial clearance, axial tooth number and radial tooth number on divergent stepped magnetic fluid seal, the pressure capability of magnetic fluid seal with an ordinary structure was comparatively analyzed through experimentation. According to the experimental results, there is no leakage or ejection of magnetic fluid from the sealing device when the critical pressure of divergent stepped magnetic fluid sealing is reached. The divergent stepped magnetic fluid seal structure performs better in pressure resistance the magnetic fluid seal with an ordinary structure. Also, the existence of axial teeth in the stepped magnetic fluid sealing structure leads to an increase in polar teeth, which not only extends the leakage path of the sealing medium but also exacerbates energy loss for the magnetic fluid carried by the sealed medium. This is effective in improving the pressure resistance of the magnetic fluid seal. When the axial tooth number reaches or exceeds the radial tooth number and the axial clearance falls below the radial clearance, the divergent stepped magnetic fluid seal with small clearance has a pressure capability that is 4.1–6 times higher than the critical pressure of ordinary magnetic fluid seal. When the axial clearance exceeds the radial clearance and the axial tooth number falls below the radial tooth number, the divergent stepped magnetic fluid seal has a critical pressure that is 1.9–3.6 times higher than that of conventional magnetic fluid seal.

3D scanning method for robotized inspection of industrial sealed parts

This work presents a novel approach for 3D scanning inspection of industrial sealed parts based on data fusion from a 2D-laser beam sensor and the motion pattern of a robotic arm. The method provides as output the 3D geometrical shape and volume of the inspected part in order to allow for automatic compliance check according to process requirements. The solution is implemented and tested in sealed riveted fasteners, which are common in the automotive and aerospace industry. The effectiveness and robustness of the method is evaluated through the comparison of the obtained results with those from a 3D laser scanner system. The evaluation campaign was performed in a noisy environment (i.e., without illumination and temperature control), representative of an industrial shop floor. Statistical analyses show the system can perform geometry prediction with an overall error of 0.340 mm and is able to reject non-compliant sealed structures with a reliability of 96.6%, confirming that the proposed method is suitable to modern collaborative robotized aerospace and automotive assembly cells.

Experimental study and numerical analysis of vacuum thermal characteristics of brush DC motor

Brush direct current (DC) motors have several qualities that make them very attractive for space flight applications. Considering the high reliability requirements of aerospace missions, the thermal characteristics and thermal failure of the brush DC motor in the space environment were studied. Using a motor thermal resistance network model, a special thermal test method was determined and combined with a thermal conductivity analysis model, the thermal parameters were obtained via item-by-item stripping, and the motor temperature field was constructed. By introducing the arc discharge factor to evaluate the electric-corrosion heat consumption, the numerical analysis results were in good agreement with the test results under the conditions of stalled rotor, normal rotation, single brush, and multiple brushes. The analysis and test results show that continuous operation for 110 s will lead to melting of the brush solder joints, and electrical corrosion heat consumption is one of the main factors that cannot be ignored. The reliability model of vacuum applications should be established in the normal working mode of at least two brushes in both the positive and negative electrodes. To improve the reliability, a sealed air-filled structure of the motor was proposed, a heat-flow co-simulation model of a continuous medium flow with a large curvature and constant without a gravity field was established, and the temperature and velocity fields under different sealed pressures were obtained. The results show that the temperature of the single brush reduced to below 140 °C from 204.5 °C in vacuum, which can meet the long-term continuous working requirement of high reliability of brush motors in space missions. In addition, it was found that with the decrease in pressure, the effect of convective heat transfer gradually weakens, the temperature gradually increases and converges to the unique heat conduction process of the gas, while the effect of convection is negligible. As the pressure continues to decrease, the sealed gas evolves from continuous medium flow to transitional and free molecular flow, and the heat conduction effect of the gas weakens again until it approaches the singleness solid conduction process.

Performance of Magnetic Fluid and Back Blade Combined Seal for Sealing Water

When sealing liquids with magnetic fluid, the interfacial stability problem caused by the interaction between the magnetic fluid and the sealed liquid leads to poor sealing performance. Centrifugal force is generated by the rotation of the sealed liquid in the back blade seal, which forms back pressure to reduce the load of the seal or prevents the sealed liquid from leaking. To reduce the influence of the shaft speed on the sealing performance, a combined magnetic fluid and back blade seal was designed for sealing liquids and a combined seal experiment stand was set up. Theoretical and experimental studies were carried out. The results showed that under a higher shaft speed, the combined seal structure had better sealing performance in which the back blade seal played the main role; the magnetic fluid seal played a major role in stopping and lowering the speed to prevent seal leakage. The combined seal could run stably under different shaft speeds.

Structure and electrochemical behavior of atmospheric plasma sprayed Cr3C2-NiCr cermet composite coatings

The technical advantages and capabilities of the Metco TriplexPro-210 atmospheric plasma spray system offers the potential to develop a new protective surface to address extreme engineering requirements. The primary goal of the present work was to investigate microstructural features, mechanical properties and the electrochemical behavior of atmospheric plasma spray Cr3C2-NiCr based coatings used as erosion and corrosion-resistant materials in seal structures of gas turbines. The commercially-available 75Cr3C2–25NiCr (Metco 81NS) was used as a reference material, and blended with B4C and Cr2O3 (weight fractions of 5% and 10%) to improve properties of the newly-developed plasma sprayed coatings. Microstructural and mechanical properties were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and through microhardness indentations. The cracks and porosity levels of the as-sprayed coatings were defined using of image analysis technqiues and desnity of the coatings was masured using Archmedie's principle. Open circuit potential and linear potentiodynamic polarization studies were carried out in artificial seawater to determine the electrochemical response and corrosion degradation mechanism of the plasma sprayed coatings. The corrosion resistance of the coatings strongly depended on the coating type, crack distribution, and porosity levels.

Research on Dynamic Seal Friction Torque Compensation for a Low-Slow-Small UAV Tracking System

To ensure reliable and accurate operation in a complex field environment for Low-Slow-Small unmanned aerial vehicle (LSS-UAV) tracking systems, a dynamic seal shafting structure consisting of a labyrinthine structure and a magnetic fluid seal ring is designed to protect important equipment, such as the infrared sensor, visible CCD and the laser rangefinder from erosion and oxidation by the external environment. A friction torque model is established for the system’s dynamic seal structure to ensure tracking accuracy of the system. The simulation results show that the closed-loop speed accuracy of the system is improved by nearly 10 fold after adding friction torque compensation. The actual test results show that including friction torque compensation can effectively reduce the start-up delay and speed fluctuation error, and the speed fluctuation error is reduced by more than 80% compared to that without friction torque compensation. The tracking accuracy of the dynamic LSS-UAV is reduced from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$56.44 \mu $ </tex-math></inline-formula> rad to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$14.86 \mu $ </tex-math></inline-formula> rad after adding friction torque compensation, which meets the requirement of smooth and accurate tracking for LSS-UAV tracking systems, and verifies the effectiveness and accuracy of compensation for the dynamic seal friction torque.

Numerical Study of the Purge Flow’s Effect on the Loss Mechanism of the Blocking and Shear Effects

The loss mechanism of shear and upstream blockage caused by the interaction of the purged flow and ingested gas needs to be systematically studied to optimize the flow near the rim. In order to study the causes and influence factors of blocking and shearing effects and quantify their losses reasonably, the three-dimensional unsteady numerical method validated by the experiment data was adopted to study the turbine with three kinds of sealing structures. The block and shear loss are quantified by integrating the dissipation coefficient in the volume where the specific aerodynamic loss occurs. The result indicated that there was a larger radial velocity and smaller tangential velocity of the purged flow relative to the main flow caused the blocking effect. Therefore, its loss is affected by the seal flow and seal structure. The shear effect is mainly affected by the tangential velocity gradient and the axial velocity gradient near the cavity exit. The contribution of the tangential velocity gradient to shear loss is increased with the enlarged sealing efficiency. Through research, it is clear that increasing the purge flow’s tangential velocity is beneficial to reducing the shear loss and has a positive significance for weakening the blocking effect in the main flow channel. Furthermore, the influence of sealing structure on blocking and shear effect must be particularly considered since both are related to sealing efficiency.

Nonuniform Clearance Effects on Pressure Distribution and Leakage Flow in the Straight-through Labyrinth Seals

Straight-through labyrinth seal is a simple and reliable noncontact seal structure widely used in aeroengines. During the actual operation of aeroengines, the labyrinth seal clearance might experience a nonuniform variation in the flow direction due to asymmetric structure and uneven temperature. In order to characterize the degree of nonuniformity, the nonuniformity coefficient is defined in current paper. The effect of nonuniform causes (rotor deformation or stator deformation), nonuniform type (convergent clearance or divergent clearance), and nonuniformity coefficient (nonuniformity degree) is carefully studied by numerical simulation. Comparative analysis has shown that there is no obvious difference in flow coefficient (less than 0.8% in current studies) between two nonuniform causes. As for nonuniform type, the nonuniformity impact of divergent type on the flow coefficient is more significant than that of convergent type, as a result of stronger axial inertia. Pressure distributions of teeth cavities indicate that the total pressure drop of the divergent type is more obvious than that of the convergent type when the pressure ratio is the same. With the same dimensionless minimum tip clearance, clearance nonuniformity would result in the increase of leakage flow of the straight-through labyrinth, particularly for the condition with small pressure ratio, large circumferential Mach number, and small dimensionless minimum tip clearance. When the nonuniformity coefficient is within the range of -0.1 to 0.1, the variation curves of nonuniformity impact factor versus the nonuniformity coefficient almost coincide (the maximum deviation is no more than 1.2%) under different operation conditions (Reynolds number, pressure ratio, circumferential Mach number, and dimensionless minimum tip clearance). Current work proves it that the effect of seal clearance nonuniformity on the leakage flow requires special attention for the refined design of aeroengines.

Approach of design of electric heaters used in non hermetically sealed structure spacecrafts

A design feature of the construction of electric heaters for non-pressurized spacecraft using a heating element in the form of a tape of a material with high resistivity, located on a flat base (electrical insulating substrate) in the form of a snake with the organization of the necessary gaps between the tapes, is revealed. A mathematical model has been developed for calculating the main design parameters of electric heaters: power, mass, heated surface area. The nomenclature of efficiency indicators used as optimization criteria has been formed: power utilization factor, filling factor of an electrically insulating substrate tape, surface density, energy-mass efficiency, thermal efficiency of heating, target efficiency. The methodological principles for ranking the requirements for the parameters of electric heaters are determined using the selected optimization criteria: the preferred use of tape materials with high resistivity and minimum thickness. A method is formulated for step-by-step calculation of the parameters of electric heaters in the presence of restrictions on the maximum heat flux density determined from the conditions for the use of electric heaters. General recommendations have been developed for choosing the parameters of electric heaters: use increased voltage, minimize the thickness of the heating element tape and the width of the gap between the tapes, determine the minimum value of the tape length for the maximum heat flux density at a given voltage rating.

Imaging of Trapped Contents in Plastic Seals via Optical Coherence Tomography

Food contents such as coffee powder, sugar, flour, cheese particles etc. trapped in plastic seals of packaged products can eventually result in air leak and potential contamination of contents due to entry of air or bacteria. This is an ongoing industry-wide problem for which no straightforward inspection solution has been identified. Backscattered light is used by optical coherence tomography (OCT) to provide cross-sectional images of micro-layers of tissues and other samples. OCT is akin to “optical ultrasound” in its utilising light waves instead of sound waves for image acquisition. As a relatively new NDT technique for non-biomedical applications, OCT might be suitable for assessment of seal integrity by revealing the presence of contents trapped within the laminates of the seal structure. This experimental study uses an OCT system (Lumedica OQ Labscope) using broadband light of 840 nm centre wavelength and capable of attaining depth resolution of 7 µm and lateral resolution of 15 µm. Our imaging results indicate that OCT can clearly show the presence of trapped powder and food particles in transparent and translucent plastic seals. Attempts to image trapped contents in opaque metallized plastic seals are largely unsuccessful. However, distortion of geometrical profile in the opaque seals can be observed by OCT and might serve as an indirect indicator of the defect.

Numerical and experimental study of divergent magnetic fluid seals with stepped pole pieces

It is crucial that the pressure resistance of ordinary magnetic fluid seals is under small clearance conditions. Therefore, a new structure for magnetic fluid seals, i. e. a dispersion type with stepped pole pieces, is proposed in this paper to further improve the pressure resistance under such operating conditions. For the divergent magnetic fluid seal with stepped pole piece, the magnetic field distribution in the clearance can be calculated, as well as the theoretical pressure resistance of the new seal structure. In this paper, it is calculated the magnetic field distribution and theoretical pressure resistance utilizing the magnetic field finite element method based on the theory of divergent magnetic fluid seals, investigated the influence of the amount of injected magnetic fluid, the number of steps, the height of the steps and the sealing gap on the pressure resistance of the new sealing structure of stepped magnetic fluid seals, as well as compared and analyzed with that of ordinary magnetic fluid seals and normal magnetic fluid seals. The results show that the pressure resistance of the normal magnetic fluid seal is significantly worse than that suggested by the split magnetic fluid seal. The pressure resistance of the stepped magnetic fluid seal increases as the number of steps increases, while the pressure resistance of the proposed structure decreases and then increases as the height of the steps increases; and the pressure resistance of the proposed structure increases and then decreases as the radial clearance increases, while the pressure resistance of the proposed structure decreases as the axial clearance increases.

Simulation and Optimization of a Multistage Interconnected Fluidized Bed Reactor for Coal Chemical Looping Combustion.

This work established a three-dimensional model of a chemical looping system with multistage reactors coupled with hydrodynamics and chemical reactions. The thermal characteristics in the chemical looping combustion (CLC) system were simulated using coal as fuel and hematite as an oxygen carrier (OC). Some significant aspects, including gas composition, particle residence time, backmixing rate, wall erosion, carbon capture rate, etc., were investigated in the simulation. Owing to the optimization by adding baffles in the fuel reactor (FR), the gas conversion capacity of the multistage FR was high, where the outlet CO2 concentration was as high as 93.8% and the oxygen demand was as low as 3.8%. Through tracing and analyzing the path of char particles, we found that the residence time of most char particles was too short to be fully gasified. The residual char will be entrained into the air reactor (AR), reducing the CO2 capture rate, which is only 80.3%. In the simulation, the wall erosion on the cyclone could be relieved by increasing the height of the horizontal pipe. In addition, improving the structure of the AR loop seal could control the residual char entrained by OC particles to the AR, and the CO2 capture rate was increased up to 90% in the multistage CLC reactor.

Design of ultrasonic leak location detector based on FPGA for spacecraft based on orbit

The research on the ultrasonic leak location technology for the spacecraft on orbit environment is of great significance to ensure the long-term on orbit normal operation, eliminate the leakage in time, maintain the cabin environment and ensure the life safety of astronauts. Taking the leakage of the cabin wall structure and gas pipeline of the space station as the research object, the aerodynamic sound source characteristics of on orbit gas leakage are analyzed, and the acoustic characteristics are analyzed and extracted. Based on the theoretical basis, an ultrasonic on orbit leak detector is developed with non-contact ultrasonic sensor and camera as the probe and FPGA as the core processor. The tests are carried out to simulate the vacuum leakage of the sealed cabin structure and the positive pressure leakage of the sealed pipeline, and the leakage ultrasonic signals under different leakage holes are analyzed and processed. According to the magnitude of Eigen values, the leakage point position is determined by patrol inspection to form the detection process. The results show that the aerodynamic ultrasonic signal of gas leakage to vacuum is weak, and the amplitude of sound source signal increases with the increase of leakage hole. The signal characteristic of leakage ultrasound is that there will be an obvious main peak in the frequency band of 40KHz ± 3kHz. The leakage of more than 0.2mm can be effectively detected through patrol inspection, and the positioning accuracy is better than ± 20mm. The research results lay a foundation for on orbit leak detection and rapid positioning of the space station.

Numerical investigation of the purge flow mechanisms and heat-transfer characteristics of turbine rim seals

In gas turbine and aeroengine, the rim seal is set between the turbine stator and rotor to prevent ingestion of the high-temperature mainstream into the rotating cavity. This study examined the sealing efficiency, flow mechanisms, and heat-transfer characteristics of three types of radial rim seal structures, which seriously affect the turbine aerodynamic efficiency and thermal safety. The flows and thermal fields were simulated using steady and unsteady numerical simulations, and dynamic modal decomposition was carried out to extract the unsteady characteristics. The results show that the seal cavity shape affects the seal efficiency. It was found that dolphin-nose with a hook and large cavity results in a higher sealing efficiency. The nose configuration of the cavity upper part also affects the outflow form of the purge flow. The purge flow from a shark-nose seal will inhibit the strength of the mainstream passage vortex, while that from a dolphin-nose seal will result in Kelvin-Helmholtz instability under certain flow rates and induce unsteady vortices. The purge flow will increase the thermal load of the blade and the hub at low flow rates. In particular, the overall thermal load with a dolphin-nose seal is 50% higher than that with a shark-nose structure. It is necessary to balance the sealing efficiency, flow instability characteristics, and heat-transfer characteristics to select an appropriate rim seal configuration.

Encapsulating hollow Fe3O4 in intertwined N-doped carbon nanofibers for high-performance supercapacitors and sodium-ion batteries

As a promising electrode for energy storage, Fe3O4 has many intriguing advantages, such as a high specific capacity, low cost, low toxicity, wide potential window and environmental benignity. However, the multi-phase changes of iron oxide during the charge and discharge process can give rise to a sharp decrease in its capacity. In addition, the low conductivity of Fe3O4 may hinder the charge transfer and ion diffusion during redox process. In order to solve the above issues, this study mainly attempts to design a nanocomposite of Fe3O4 encapsulated in intertwined N-doped carbon nanofibers (CNFs) via using electrospinning and high-temperature calcination. The sealed structure can efficiently relieve the volume effect of Fe3O4 and raise the stability of electrodes. While a 3-dimensional interconnected conductive network composed of CNFs can increase the electroconductibility of electrodes. At the same time, the N-doping increases active sites on the surface of CNFs, providing more space for ions and charges storage. Herein, different amounts of Fe3O4 are encapsulated in N-doped CNFs (Fe3O4-CNFs). Fe3O4-CNFs with 40 % content of Fe3O4 (4Fe3O4-CNFs) deliver splendid electrochemical performances for all-solid-state supercapacitors and sodium-ion batteries. The specific capacitance of 4Fe3O4-CNFs supercapacitor is 184.5 F g−1 and maintains 86.2 % of initial capacity at 2 A g−1 after 5000 times. Furthermore, 4Fe3O4-CNFs as the anode for the half cell vs. Na+/Na demonstrate a splendid specific capacity of 628.1 mAh g−1 at 0.02 A g−1 and can maintain 358.1 mA h g−1 after cycling for 200 laps at 500 mA g−1. Therefore, 4Fe3O4-CNFs can be widely used in energy storage.

Testing and evaluation for long-term skid resistance of asphalt pavement composite seal using texture characteristics

As a common means to improve the skid resistance of asphalt pavement, chip seal is widely used for road surface treatment and preventive maintenance. As the aggregate is progressively dislodged under repeated wheel loads, continuous loss of the surface texture characteristics occurs, and its skid resistance increasingly declines. Therefore, it is necessary to further refine the process of chip seal. In addition, in order to scientifically evaluate its performance and accurately predict the deterioration, the relationship between the surface texture characteristics and the skid resistance needs to be quantitatively established. In this paper, a composite seal structure was proposed by applying sand-containing fog seal layer on top of chip seal. Firstly, four seal schemes (i.e., 3–5 mm chip seal, 5–9.5 mm chip seal, 3–5 mm composite seal and 5–9.5 mm composite seal) were designed and loaded by a four-wheel rotary accelerated abrader. Secondly, the skid resistance indexes of each scheme were investigated under different abrasion times using pendulum meter and sand patch method. In this process, the three-dimensional texture characteristic parameters (i.e., Ssk, Spd, Spc, Vmp and Vmc) of the specimen surface were also obtained by laser scanning. Finally, by analyzing the data, the relationship between the seal texture characteristic parameter and the skid resistance index was established, and the decay law prediction model of the skid resistance for four seal schemes was derived. It is found that the pendulum value and texture depth of the seal decreased with the increase of abrasion times, but the composite chip seal can reduce the decreasing rate of skid resistance index. Sq, Spd, Spc and Vmc showed good synergistic decay laws with the British pendulum number (BPN) and mean texture depth (MTD), among which Spc had the best correlation and can be used as an parameter to characterize the skid resistance of the seal. The relationship and decay prediction model established in this paper can be used to characterize the skid resistance of chip seal and predict the decay law of the skid resistance.

Research on pipeline connection structure of microwave load water-cooling system for spacecraft thermal test

The microwave load water-cooling system was operated in a vacuum cold black environment, and the pressure difference between the inside and outside of the water pipe could reach 0.3 to 0.4 MPa. To ensure the tightness of the water pipe, a conical seal structure was selected, the macro-static model and micro-boundary element contact model were established for the two forms with and without the Viton seal. The macro model simulation was performed by the finite element method to obtain the stress distribution inside the conical structure under different preload stress, the relationship between the contact pressure of the conical sealing interface and the contact area of the O-ring sealing interface as a function of preload stress; the method was used to calculate the micro-contact model, and the critical contact pressure and contact area to achieve the sealing requirements were obtained respectively without Viton seal and with Viton seal. As a result, a conical seal structure with a Viton seal was finally chosen for application. After verification, the structure meets the requirements for the use of microwave load water-cooling systems during the vacuum thermal test.

Finite Element Analysis and Experimental Study on Magnetorheological Fluid Seal of the Hydraulic Cylinder

In order to solve the leakage problem of the engineering mechanical hydraulic cylinder, a magnetorheological fluid (MRF) seal structure with a multistage source is designed. The magnetic field in the gap of the sealing structure is analyzed by ANSYS finite element analysis method, the influence about the number of magnetic sources and the length of pole teeth on the pressure capability of the MRF seal is studied, and the results are analyzed. The results show that the suitable number of magnetic sources is 10; The length of the pole teeth with the best magnetic concentrating effect is 0.7 mm. Then, the influence of the MRF injection volume, reciprocating speed, reciprocating distance and holding pressure time of the hydraulic cylinder on the MRF sealing pressure capability is studied. The experimental results show that the maximum pressure capacity can be achieved when the MRF injection volume is 12 ml. With the increase of reciprocating speed, the pressure capability of the MRF seal decreases obviously. With the increase of reciprocating distance and holding time, the sealing pressure capability has no obvious change. Through the finite element analysis and experimental study of the MRF seal, it is of great significance to develop a device with high sealing performance suitable for the hydraulic cylinders.