Test analysis of gas film stiffness and system damping of spiral groove dry gas seal

2016 ◽  
Author(s):  
Xuexing Ding ◽  
Junjue Lu ◽  
Weizheng Zhang ◽  
Xiao Zhai
Keyword(s):  
Spiral Groove ◽  
Test Analysis ◽  
Dry Gas Seal ◽  
Film Stiffness

Performance Analyses of the Spiral Groove Dry Gas Seal with Inner Annular Groove

2013 ◽  
Vol 420 ◽  
pp. 51-55 ◽  
Author(s):  
Ying Li ◽  
Peng Yun Song ◽  
Heng Jie Xu
Keyword(s):  
Pressure Control ◽  
Operating Conditions ◽  
Performance Parameters ◽  
Spiral Groove ◽  
Dry Gas Seal ◽  
Sealing Performance ◽  
The Common ◽  
The Difference ◽  
Film Stiffness ◽  
The Given

In order to improve the performance of the spiral groove dry gas seal (S-DGS), the spiral groove dry gas seal with an inner annular groove (AS-DGS) was invented. Based on the narrow groove theory, the sealing performance parameters of the AS-DGS were gained by using approximate analytical method to solve the gas film pressure control equations, and the results were compared with those of the common S-DGS. The results show that, in the given operating conditions, the opening force of AS-DGS is smaller than that of the S-DGS with the difference less than 0.5%, and the film stiffness is larger than that of the common S-DGS with the difference less than 5% in the case of low-speed or high-pressure operation, but the leakage is a little larger.

Enhancing Film Stiffness of Spiral Groove Dry Gas Seal via Shape Modification at Low Speed: Numerical Results and Experiment

2019 ◽  
Vol 62 (6) ◽  
pp. 931-942 ◽  
Author(s):  
Jinbo Jiang ◽  
Xudong Peng ◽  
Cong Zong ◽  
Wenjing Zhao ◽  
Yuan Chen ◽  
...  
Keyword(s):  
Numerical Results ◽  
Spiral Groove ◽  
Shape Modification ◽  
Low Speed ◽  
Dry Gas Seal ◽  
Film Stiffness

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.

The performance of spiral groove dry gas seal under choked flow condition considering the real gas effect

2019 ◽  
Vol 234 (4) ◽  
pp. 554-566
Author(s):  
Hengjie Xu ◽  
Pengyun Song ◽  
Wenyuan Mao ◽  
Qiangguo Deng
Keyword(s):  
Carbon Dioxide ◽  
Flow Condition ◽  
Ideal Gas ◽  
Leakage Rate ◽  
Spiral Groove ◽  
Real Gas ◽  
Dry Gas Seal ◽  
Choked Flow ◽  
Real Gas Effect ◽  
Gas Effect

By taking carbon dioxide and hydrogen as lubricating gas, respectively, this paper presents an analysis on the pressure characteristics and temperature distribution of spiral groove dry gas seal which influenced by real gas effect under choked flow condition. Numerical results show that the deviation between real gas and ideal gas, which expressed by the deviation degree between compressibility factor Z and 1, is the main reason for real gas effect affecting sealing performance. Compared with ideal gas model, real gas effect raises exit pressure, opening force, leakage rate, Mach number in dam region, and temperature for carbon dioxide ( Z < 1), while it decreases those characteristics for hydrogen ( Z > 1) under the same operating conditions. In addition, choked flow effect increases opening force and reduces leakage rate and temperature-drop between entrance and exit of sealing clearance. Meanwhile, it may cause an unstable behavior for the seal.

Dynamic coupling correlation of gas film in dry gas seal with spiral groove

2014 ◽  
Vol 27 (4) ◽  
pp. 853-859 ◽  
Author(s):  
Zhengxian Liu ◽  
Musu Wang ◽  
Yue Zhou ◽  
Ningning Wu
Keyword(s):  
Dynamic Coupling ◽  
Spiral Groove ◽  
Dry Gas Seal ◽  
Coupling Correlation

Performance of Externally Pressurized Dry Gas Seal

2011 ◽  
Vol 335-336 ◽  
pp. 610-614 ◽  
Author(s):  
Wei Bing Zhu ◽  
Sheng Ren Zhou ◽  
He Shun Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Reynolds Equation ◽  
Dry Gas Seal ◽  
Supply Pressure ◽  
Lubrication Equation ◽  
Air Supply ◽  
Computer Numerical Simulation ◽  
Film Stiffness

By adding the flow rate of throttle orifice to conventional stable externally pressurized gas lubrication equation, the Reynolds equation for externally pressurized dry gas seal with orifice compensation is established. The solution of the equation is studied by functional extremum algorithm and finite element method, and the computer numerical simulation is carried out in Matlab software. The effects of air supply pressure, numbers and diameter of throttle orifice, on face opening force and gas film stiffness are discussed in detail.

The Optimization of Stiffness Performance of Upstream Pumping Mechanical Seal Based on the Response Surface Method

2015 ◽  
Author(s):  
Huilong Chen ◽  
Jinfeng Liu ◽  
Tong Li ◽  
Kunteng Ren ◽  
Bin Wang
Keyword(s):  
Liquid Film ◽  
Groove Depth ◽  
Diameter Ratio ◽  
Width Ratio ◽  
Mechanical Seal ◽  
Spiral Groove ◽  
Surface Method ◽  
Film Stiffness ◽  
Face Morphology ◽  
Morphology Parameters

The face shape optimization of spiral groove upstream pumping mechanical seal is of great significance. The liquid film stiffness was calculated by considering the cavitation model and dynamic grid in this paper. The regression model was established according to the results of the end face morphology parameters and the stiffness performance. The equivalent cloud images were drawn by using Matlab software. The response surface method is used to analyze the interaction of the upstream pumping mechanical seal face morphology parameters of the groove depth, spiral angle groove diameter ratio and groove width ratio on the stiffness performance. Finally, the numerical simulation of the mechanical seal micro clearance flow is verified. The results show that spiral groove depth should be between 3 and 10 μm. The liquid film stiffness value is becoming smaller with the increase of the helical angle. The best value is around 16°; The influence of the groove diameter ratio and the groove width ratio to the liquid film stiffness is symmetrical distribution basically. And it is better to take 0.5 and 0.4 respectively.

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.

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