Bidirectional Trapezoidal Versus Unidirectional Spiral Groove Performance in Dry Gas Seals

2021 ◽  
Vol 14 (3) ◽  
pp. 220-228
Author(s):  
Wanjun Xu ◽  
Yongwei Tian ◽  
Ying Song ◽  
Yaoyao Xu
Keyword(s):  
Spiral Groove ◽  
Gas Seals

The influence of 3-DOF film thickness disturbance on transient performance of typical spiral groove dry gas seals

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuan Chen ◽  
Hao Shang ◽  
Xiaolu Li ◽  
Yuntang Li ◽  
Bingqing Wang ◽  
...  
Keyword(s):  
Film Thickness ◽  
Degrees Of Freedom ◽  
Thickness Distribution ◽  
Transient Performance ◽  
Spiral Groove ◽  
Double Row ◽  
Content Type ◽  
Dry Gas Seal ◽  
Sealing Performance ◽  
Gas Seals

Purpose The purpose of this paper is to investigate the influence rule and mechanism of three degrees of freedom film thickness disturbance on the transient performance of spiral groove, upstream pumping spiral groove dry gas seal (UP-SDGS) and double-row spiral groove dry gas seal (DR-SDGS). Design/methodology/approach The transient performance of spiral groove, UP-SDGS and DR-SDGS are obtained by solving the transient Reynolds equation under different axial and angular disturbance coefficients. The transient and steady performance of the above-mentioned DGSs are compared and analyzed. Findings The film thickness disturbance has a remarkable impact on the sealing performance of DGS with different structures and the calculation deviations of the leakage rate of the UP-DGS will increase significantly if the film thickness disturbance is ignored. The axial and angular disturbance jointly affect the film thickness distribution of DGS, but there is no significant interaction between them on the transient sealing performance. Originality/value The influence mechanism of axial disturbance and angular disturbance on the transient performance of typical SDGSs behavior has been explained by theory. Considering small and large disturbance, the interaction between axial disturbance and angular disturbance on the transient performance have been studied.

Effect of Frequency Excitation on Force Coefficients of Spiral Groove Gas Seals

1999 ◽  
Vol 121 (4) ◽  
pp. 853-861 ◽  
Author(s):  
Nicole Zirkelback ◽  
Luis San Andre´s
Keyword(s):  
Finite Element ◽  
Compressible Fluid ◽  
Fluid Model ◽  
Dynamic Performance ◽  
Excitation Frequency ◽  
Spiral Groove ◽  
Thrust Bearings ◽  
Force Coefficients ◽  
Frequency Excitation ◽  
Gas Seals

An analysis for compressible fluid spiral groove thrust bearings (SGTBs) and face seals (SGFSs) is presented. Zeroth- and first-order equations rendering the static and dynamic performance of SGFSs, respectively, are solved using the finite element method with a successive approximation scheme. Comparison of the present isothermal compressible fluid model for static and dynamic SGTB and SGFS performance validates previous narrow groove theory, finite difference, and finite element analyses. A discussion follows to indicate the importance of using a small number of grooves to prevent instabilities from negative damping in SGTBs and SGFSs when pressurization is lost. Force coefficients are shown to reach asymptotic limits as the axial excitation frequency increases.

Hydrodynamics and Sonic Flow Transition in Dry Gas Seals

2014 ◽  
Author(s):  
Azam Thatte ◽  
Xiaoqing Zheng
Keyword(s):  
Linear Partial Differential Equation ◽  
Hydrodynamic Pressure ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Spiral Groove ◽  
Local Pressure ◽  
Choked Flow ◽  
Gas Seals ◽  
Film Stiffness

Dry gas seals (DGS) are widely used in turbomachinery applications. They are recently being also recommended for sealing novel super critical CO2 turbomachinery space. However, these seals can render interesting behavior under certain operating conditions which needs to be carefully monitored so that intended level of dynamic characteristics can be achieved. The ability of these seals to maintain low leakage by riding at small clearances makes them an attractive solution where secondary flows need to be minimized. To understand the significance of some of the key design features of these seals, in this work an analysis on a gas lubricated spiral groove dry gas seal is presented. Equations in polar coordinates governing the compressible flow through the DGS gap and a numerical method to solve such non-linear partial differential equation is presented. The resulting sets of equations are solved for hydrodynamic pressure distribution and the axial separation force and the film stiffness at the rotor-stator interface is calculated. A detailed study on key spiral groove features is then performed to investigate the effect of spiral angle, groove depth, groove pitch and dam width ratio on the hydrodynamic pressure generation capacity, film stiffness and hence on overall performance of the DGS. Another important phenomenon that can occur in DGS under high operating pressure is the sonic transition. It is shown that choked flow under such conditions can take place over the dam section of the seal which manifests itself into large local pressure and temperature variations and can result into dynamic instabilities.

scholarly journals A comprehensive multi-objective, multi-parameter and multi-condition optimization of a spiral groove in dry gas seals

2020 ◽  
Author(s):  
Jinbo Jiang ◽  
Wenjing Zhao ◽  
Jie Jin ◽  
Jiyun Li ◽  
Xudong Peng
Keyword(s):  
Genetic Algorithm ◽  
Working Conditions ◽  
Optimization Problems ◽  
Geometric Parameters ◽  
The Other ◽  
Operating Efficiency ◽  
Spiral Groove ◽  
Gas Seals ◽  
Film Stiffness ◽  
Dimensional Optimization

Abstract Dry gas seals are widely used in rotating equipment for fluid leakage control and operating efficiency enhancement. Multi-dimensional optimization of geometric parameters of the spiral groove was conducted with considering the comprehensive effect of working conditions, objective functions and the other geometric parameters. Different optimization methods were proposed for solving the multi-dimensional optimization problems. The optimal values of groove width ratio, groove length ratio and spiral angle for the excellent steady performance of spiral grooves under different working conditions were obtained by employing a genetic algorithm and loop iteration optimization method. The performance comparison of two dry gas seals with different geometric parameters was conducted experimentally to verify the effectiveness of numerical results. The results showed that optimal geometric parameters of the spiral groove were significantly influenced by working conditions, objective function and the other geometric parameters. Maximum film stiffness and stiffness-leakage ratio of the spiral groove dry gas seal obtained by genetic algorithm enhanced up to 30% and 45% larger than those obtained by the conventional single factor optimization. The film stiffness and stiffness-leakage ratio were more sensitive to geometric parameters of a spiral groove than that of opening force. The optimization results obtained in this paper provide a theoretical and experimental reference for the design of dry gas seals in different working conditions to meet various sealing performance requirements.

Performance Characteristics of Spiral-Groove and Shrouded Rayleigh Step Profiles for High-Speed Noncontacting Gas Seals

1969 ◽  
Vol 91 (1) ◽  
pp. 60-68 ◽  
Author(s):  
H. S. Cheng ◽  
V. Castelli ◽  
C. Y. Chow
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Performance Characteristics ◽  
Spiral Groove ◽  
Typical Performance ◽  
The Difference ◽  
Gas Seals ◽  
Groove Seal ◽  
Film Characteristics ◽  
Film Profile

Current methods in gas lubrication have been used in this paper to analyze the gas-film characteristics in a high-speed, face-type gas seal. Detailed analyses are presented for two different surface geometries, the spiral-groove-orifice seal and the shrouded Rayleigh step seal. Results are presented in three parts. The first part shows the performance of a spiral-groove seal without the orifices, and also the difference in performance when the grooves are located at the high pressure, low pressure, or both sides. The second part gives typical performance of a nonparallel film profile for the spiral-groove-orifice seal as well as for the shrouded Rayleigh step seal. In the last part, a comparison is made between the two seal geometries on their tolerance to coning or dishing under a constant seal load.

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