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Aiming at the compliant end face gas film seal structure, based on the linearized Boltzmann equation, the Poiseuille flow coefficient is introduced, and the generalized Reynolds equation and the sealing performance parameter solution formula considering the boundary slip flow effect are established. Through Newton–Raphson iterative calculation, the degree of influence of the slip flow effect under different working conditions is analyzed, and the internal relationship between structural parameters and sealing performance is compared. The results show that the slip flow effect can have a large impact on the pressure distribution in the fluid field close to the low-pressure side. Due to the existence of the step phenomenon of boundary velocity, it is not conducive to increasing the gas film opening force and controlling the mass leakage rate, but it can play a positive role in reducing the viscous friction power consumption. In the case of a smaller sealing gas film thickness and lower medium pressure, the slip flow effect is significant, which will have a greater impact on the sealing performance, and at this time, the slip flow effect can not be ignored. In addition, the change in seal structure parameters will also have a large impact on the sealing performance. With an increase in the wave foil thickness, the compliant end face evolves towards the rigid end face, the fluid wedge effect is weakened, and the gas film opening force and mass leakage rate are reduced. The stiffness-to-leakage ratio shows a strong nonlinear decreasing trend with an increase in the wave foil chord length and pitch, which eventually tends to a stable value. The results of this paper provide a theoretical basis for the matching design of the structural parameters of compliant end-face gas film seals under different service conditions. [ABSTRACT FROM AUTHOR]

In recent years, the use of dry gas seal technology in high-end industrial applications has become increasingly widespread. Existing research has primarily focused on unidirectional grooves. This study introduces an innovative approach by incorporating bidirectional grooves inspired by the biomimetic design of a carp tail, aiming to enhance sealing performance. The analysis of flow-field characteristics was conducted using Fluent software to evaluate the effect of different groove designs on sealing efficacy. The results indicate that curved grooves are more effective in directing gas flow and reducing fluid dynamic losses, thus improving the overall sealing efficiency. In particular, the outer-curved carp-tail groove exhibited superior dynamic pressure effects and reduced pressure drops across various operating conditions. The optimal radial dam-to-groove width ratio ranged from 3.8 to 4.1, and the optimal groove depth ranged from 6.5 to 9.6 μm. This investigation focused on the design and performance evaluation of biomimetic carp-tail grooves for dry gas seals, presenting a novel groove configuration for end-face sealing and further advancing the theoretical understanding of dry gas seals. [ABSTRACT FROM AUTHOR]

The emergence of dry gas seals has revolutionized the form of fluid sealing. The traditional research and analysis of dry gas seals is carried out by considering the lubricating medium gas as an ideal gas, but at this stage, the sealing application environment is complicated, so it is necessary to consider the real gas effect of the lubricating medium gas to expand and break through the design system of dry gas seals. We choose seven common lubricating media in dry gas seal applications and screen the optimal density expression of the real gas using different real gas equations of state. Then, we study the extent to which the compression factors of different lubricating gases deviate from the ideal gas and analyze the errors of different real gas equations of state. These results can provide an optimal expression to clarify the mechanism by which the real gas effect affects the dry gas seal performance, which helps to grasp the nature of dry gas seals, predict the dry gas seal behavior, and guide the dry gas seal application. [ABSTRACT FROM AUTHOR]

Traditional oil seals are insufficient for the high-speed and bi-directional rotation of new energy electric vehicles. Therefore, we developed a Python program focusing on micro-groove pump seals and examined the unexplored non-contact oil–air biphasic internal end-face seals. Real gas effects were described using the virial and Lucas equations. We introduced an oil–air ratio to determine the equivalent density and viscosity of the two-phase fluid in the seal. Furthermore, we solved the compressible steady-state Reynolds equation using the finite difference method. Analysing the seal's pumping mechanisms and the effects of operating parameters on sealing performance, we assessed 17 types of hydrodynamic grooves. The results demonstrate that inverse fir tree-like grooves perform well under typical sealing conditions. Under the conditions given in this study, the pumping rate of the optimal groove type compared to other groove types even reached 633.54%. In the oil–air biphasic state, the micro-groove pump seal exerts significant dynamic pressure on the sealing surface. Seal opening force increases with rotational velocity, oil–air ratio, and inlet pressure but decreases with temperature. The pumping rate first increases and then decreases with rotational velocity, increases with oil–air ratio and temperature, and then decreases with inlet pressure. Some special working points require consideration in sealing design. Our results provide insights into designing micro-grooved pumping seals for new energy electric vehicles. [ABSTRACT FROM AUTHOR]

In order to explore the influence of the structural parameters of the split type carbon ring seal on the radial deformation of the sealing surface,the numerical calculation was used to solve the pressure control Reynolds equation to obtain the gas film pressure. The fluid-solid thermal coupling simulation was conducted in combination with the finite element analysis software to explore the influence of different structural parameters on the radial deformation of the carbon ring under specific working conditions,and the radial deformation characteristics of the main sealing surface was analyzed. The results show that the installation position of the anti-rotation pin has the greatest influence on the radial deformation of the carbon ring, and the radial deformation can be reduced by selecting the appropriate installation position. When the external convex structure is uneven and the ratio of the center angle is large, the radial deformation is small. The larger the ratio of the lap joints on both sides, the smaller the radial deformation. The selection of tension spring and compression spring has little influence on the radial deformation of carbon ring.The larger the spring pressure, the smaller the radial deformation. However, when the spring pressure is too high,it can easily lead to increased wear, fracture of the carbon ring,and even the failure of seal. The refore, appropriate spring pressure should be selected based on actual working conditions. The research results provide a reference for the structural optimization design of split carbon ring seals. [ABSTRACT FROM AUTHOR]

High-performance aeroengine design is an important component of modern industry, and advanced sealing technology is a key technology to meet the engine fuel consumption rate, thrust-to-weight ratio, pollutant emission, durability, and lifetime. Reducing the internal airflow leakage of the engine through a sealing technology can improve the performance and efficiency of the engine. In this paper, the typical sealing technology for an aeroengine is introduced in more detail, including the structural characteristics and use limitations of the labyrinth seal, brush seal, honeycomb seal, gas film face seal, and cylindrical gas film seal. It focuses on the development history, typical structure type, working principle, basic technology research method, steady-state performance, dynamic characteristics, multi-physical field coupling, structural deformation, experimental testing, processing technology. Finally, it summarizes the problems and future development trends of the current application of the cylindrical gas film seal in aeroengines, and points out that the seal performance test and evaluation based on advanced composite sensor technology and the innovative design of the seal based on new material, a new principle, and a new structure will be the new research direction. [ABSTRACT FROM AUTHOR]

In order to avoid the design of the rotor of the dry gas seal high speed test stand occur resonance phenomenon during high speed running,the transfer matrix method was applicated to calculate the natural frequency.Then it obtains that its natural frequency is 14044.586r/min when the dry gas seal static and ring `s quality is 33.78 kg in rotor system,and using the finite element method analysis the modes of the rotor system when it is operating in the vicinity of its natural frequency,then it will get the modal figure with four modal value.Comparative and analysis the results of the two methods,though simplified model are not the same,the results are similar.And the design of speed can meet the requirements,so it can describe the design of the rotor system is reasonable.

The overall process and method of mechanical seal condition monitoring and fault diagnosis were expounded. From the five aspects of signal acquisition, noise reduction and reconstruction, feature extraction, pattern recognition and life prediction, the research progress of mechanical seal condition monitoring and fault diagnosis technology was summarized, and the existing problems were analyzed. The future development direction of mechanical seal intelligence was suggested. [ABSTRACT FROM AUTHOR]

Due to the weak characteristic information of vibration signal and strong external noise interference,the vibration signal during the operation of dry gas seal is difficult to reflect the tribological characteristics of dry gas seal.Aimed at the above problems and the difficulty of separating vibration signal from noise, a signal denoising method based on the combination of CEEMDAN (complete ensemble empirical mode analysis with adaptive noise) and ICA (independent component analysis) was proposed. The acceleration signal of dry gas seal collected by experiments was first decomposed by CEEMDAN to get IMF component.The corresponding independent component was obtained by ICA transformation and its fuzzy entropy value was calculated.The component whose fuzzy entropy value did not meet the condition was set to zero,and the component which met the condition was reconstructed to get the denoising signal.The algorithm was analyzed and verified by using the dry gas seal acceleration test signal.It is proves that the method proposed is more effective than other traditional noise reduction methods,which provides a new way for fault diagnosis of dry gas seal in the future. [ABSTRACT FROM AUTHOR]

The performance of mechanical seal has an important influence on the thermal control efficiency and stable operation of marine core equipment of submarine hybrid pump. Based on the working state of the hybrid pump and the service environment of the mechanical seal, the three-dimensional model of seal ring-liquid film multi-body structure was established. Considering the multi-field synergy of thermal effect, force effect and fluid effect, the performance change law of seal ring-liquid film multi-body structure under simulated actual working conditions was studied by using thermal-fluid-solid coupling numerical simulation technology, and the lubrication characteristics, mechanical characteristics and temperature characteristics of seal ring-liquid film multi-body structure under different working conditions were obtained. The results show that in the multi-body structure of the seal ring-liquid film, the maximum deformation and maximum temperature of seal ring appear in the spiral groove area. With the increase of speed and pressure, the seal opening force and leakage increase, but the influence of speed is obviously greater than that of pressure. The influence of pressure on stress is significantly greater than that of speed, especially when the pressure exceeds 6 MPa, the contact pressure of sealing face is relatively uneven. Due to the effect of convective heat transfer and air flow viscous shear,the speed has a greater effect on the temperature of the seal end face than the pressure, especially in the low speed region of 500 r/min, the temperature of the ring-liquid film multi-body structure exceeds 75 T, and the temperature difference at different radial positions is also very obvious, which will cause damage to the mechanical seal. [ABSTRACT FROM AUTHOR]