Advanced Analysis of Multi-Ring Liquid Seals

1992 ◽  
Vol 114 (1) ◽  
pp. 42-46 ◽  
Author(s):  
S. W. Reedy ◽  
R. G. Kirk
Keyword(s):  
High Pressure ◽  
Equilibrium Position ◽  
Analysis Procedure ◽  
Analysis Program ◽  
Centrifugal Compressors ◽  
Curve Fit ◽  
Ring Seal ◽  
Computer Codes ◽  
Advanced Analysis

The equilibrium position of multi-ring seal assemblies is of major importance to the designer of high pressure centrifugal compressors. Typical computer codes now use a curve-fit of the Short Bearing Sommerfeld Number for eccentricity evaluation with the assumption that all rings in the assembly will always operate at the same eccentricity. The results from the recently developed seal analysis program, SEALS, have shown that the equal eccentricity assumption for multi-ring seals is questionable. This paper will review the analysis procedure used in SEALS, and present the results of an eccentricity evaluation comparison with a seal analysis program currently being used in industry.

Explosive Decompression Resistance of Centrifugal Compressor O-Ring Seals: A Comparative Test Summary and Procedure

1988 ◽  
Vol 110 (2) ◽  
pp. 289-294 ◽  
Author(s):  
W. N. Shade ◽  
D. W. Legg
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Centrifugal Compressor ◽  
Atmospheric Pressure ◽  
Comparative Test ◽  
Test Results ◽  
Test Rig ◽  
Centrifugal Compressors ◽  
Ring Seal ◽  
Sealing Elements

Explosive decompression is a phenomenon that can destroy O-ring sealing elements in high-pressure (>3.4 MPa) natural gas compressors during rapid venting to atmospheric pressure. A test rig and procedure have been developed to identify important parameters influencing O-ring seal explosive decompression failure, consistent with utilization of these seals in high-pressure centrifugal compressors. The test rig and procedure are described and comparative test results presented.

Roles of vanes in diffuser on stability of centrifugal compressor

2019 ◽  
Vol 233 (14) ◽  
pp. 5380-5392
Author(s):  
Wangzhi Zou ◽  
Xiao He ◽  
Wenchao Zhang ◽  
Zitian Niu ◽  
Xinqian Zheng
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Centrifugal Compressors ◽  
Compression System ◽  
The Stability ◽  
Rotating Instability

The stability considerations of centrifugal compressors become increasingly severe with the high pressure ratios, especially in aero-engines. Diffuser is the major subcomponent of centrifugal compressor, and its performance greatly influences the stability of compressor. This paper experimentally investigates the roles of vanes in diffuser on component instability and compression system instability. High pressure ratio centrifugal compressors with and without vanes in diffuser are tested and analyzed. Rig tests are carried out to obtain the compressor performance map. Dynamic pressure measurements and relevant Fourier analysis are performed to identify complex instability phenomena in the time domain and frequency domain, including rotating instability, stall, and surge. For component instability, vanes in diffuser are capable of suppressing the emergence of rotating stall in the diffuser at full speeds, but barely affect the characteristics of rotating instability in the impeller at low and middle speeds. For compression system instability, it is shown that the use of vanes in diffuser can effectively postpone the occurrence of compression system surge at full speeds. According to the experimental results and the one-dimensional flow theory, vanes in diffuser turn the diffuser pressure rise slope more negative and thus improve the stability of compressor stage, which means lower surge mass flow rate.

Lateral Equilibrium Position Analysis Program With Applications to Electric Submersible Pumps

2017 ◽  
Author(s):  
Clay S. Norrbin ◽  
Dara W. Childs
Keyword(s):  
Equilibrium Position ◽  
Static Equilibrium ◽  
Analysis Program ◽  
Eccentricity Ratio ◽  
Vertical Orientation ◽  
Maximum Curvature ◽  
First Finding ◽  
Static Eccentricity ◽  
Lateral Equilibrium ◽  
Vertical Case

The long length of sub-sea Electric Submersible Pumps (ESPs) requires a large amount of annular seals. Loading caused by gravity and housing curvature changes the Static Equilibrium Position (SEP) of the rotor in these seals. This analysis predicts the SEP due to gravity and/or well curvature loading. The analysis also interfaces displays the rotordynamics around the SEP. A static and rotordynamic analysis is presented for a previously studied ESP model. This study differs by first finding the SEP and then performing a rotordynamic analysis about the SEP. Predictions are shown in a horizontal and a vertical orientation. In these two configurations, viscosities and clearances are varied through 4 cases: 1X 1cP, 3X 1cP, 1X 30cP, and 3X 30cP. In a horizontal, straight-housing position, the model includes gravity and buoyancy on the shaft. At 1cP-1X and 1cP-3X, the horizontal statics show a moderate eccentricity ratio for the shaft with respect to the housing. With 30cP-1X, the predicted static eccentricity ratio is low at 0.08. With 30cP-3X, the predicted eccentricity ratio increases to 0.33. Predictions for a vertical case of the same model are also presented. The curvature of the housing is varied in the Y-Z plane until rub or close-to-wall rub is expected. The curvature needed for a rub with a 1X 1cP fluid is 7.5 degrees of curvature. Curvature has little impact on stability. With both 1X 30cP and 3X 30cP, the maximum curvature for a static rub are over 25 degrees of curvature. Both 1X 30cP and 3X 30cP remain unstable with increasing curvature.

Lateral Equilibrium Position Analysis Program With Applications to Electric Submersible Pumps

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Clay S. Norrbin ◽  
Dara W. Childs
Keyword(s):  
Equilibrium Position ◽  
Static Equilibrium ◽  
Analysis Program ◽  
Eccentricity Ratio ◽  
Vertical Orientation ◽  
Maximum Curvature ◽  
First Finding ◽  
Static Eccentricity ◽  
Lateral Equilibrium ◽  
Vertical Case

The long length of subsea electric submersible pumps (ESPs) requires a large amount of annular seals. Loading caused by gravity and housing curvature changes the static equilibrium position (SEP) of the rotor in these seals. This analysis predicts the SEP due to gravity and/or well curvature loading. The analysis also displays the rotordynamics around the SEP. A static and rotordynamic analysis is presented for a previously studied ESP model. This study differs by first finding the SEP and then performing a rotordynamic analysis about the SEP. Predictions are shown in a horizontal and a vertical orientation. In these two configurations, viscosities and clearances are varied through four cases: 1X 1cP, 3X 1cP, 1X 30cP, and 3X 30cP. In a horizontal, straight-housing position, the model includes gravity and buoyancy on the shaft. At 1cP-1X and 1cP-3X, the horizontal statics, show a moderate eccentricity ratio for the shaft with respect to the housing. With 30cP-1X, the predicted static eccentricity ratio is low at 0.08. With 30cP-3X, the predicted eccentricity ratio increases to 0.33. Predictions for a vertical case of the same model are also presented. The curvature of the housing is varied in the Y–Z plane until rub or close-to-wall rub is expected. The curvature needed for a rub with a 1X 1cP fluid is 7.5 deg of curvature. Curvature has little impact on stability. With both 1X 30cP and 3X 30cP, the maximum curvature for a static rub is over 25 deg of curvature. Both 1X 30cP and 3X 30cP remain unstable with increasing curvature.

Numerical Simulation Analysis of Centrifugal Pump Floating Ring Seal

2011 ◽  
Vol 317-319 ◽  
pp. 2148-2151
Author(s):  
Jian Yong Han ◽  
Guo Jing Chen
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Centrifugal Pump ◽  
Simulation Analysis ◽  
Maximum Pressure ◽  
Force Analysis ◽  
Sealing Ring ◽  
Fluent Software ◽  
Ring Seal ◽  
Liquid Flows

According to the studying on the force analysis of floating ring of centrifugal pump, the paper think that floating ring stress will change with the change of centrifugal pump’ s condition. Using fluent software, the floating ring seal was simulated and analyzed. Results show that the liquid force acted on the floating ring is nonuniform and asymmetrical as wedging effect, and that section maximum pressure is not lies in the smallest clearance place, but in the wedge area where liquid flows to the minimum clearance, because the effect of Leak resistance is better in high pressure than low pressure. The leakage decreases and liquid resistance increases with the increases of RPM. The leakage increases with the increases of differential pressure in sealing ring sides and eccentricity. Pressure distribution within the seal clearance is not uniform with the increases of eccentricity.

O‐Ring Seal for High Pressure Tensile Tester

1969 ◽  
Vol 40 (7) ◽  
pp. 966-966
Author(s):  
D. R. McCann ◽  
P. F. Hettwer ◽  
J. C. Uy
Keyword(s):  
High Pressure ◽  
Tensile Tester ◽  
Ring Seal

A Performance Autopsy of Three Centrifugal Compressors for a Small Gas Turbine

2010 ◽  
Author(s):  
Colin Rodgers ◽  
Dan Brown
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Radial Flow ◽  
Pressure Ratio ◽  
Test Results ◽  
Design Features ◽  
Centrifugal Compressors ◽  
High Pressure Ratio ◽  
Flow Type ◽  
The One

Three 140mm tip diameter centrifugal compressors were designed and tested to determine the one exhibiting the best performance most suitable for eventual application to a small 60KW radial flow type gas turbine. The design features, and stage test results of these three moderately high pressure ratio impellers are presented, together with a comparison of their respective test and CFD computed performance maps.

Rotordynamic Force Prediction of a Shrouded Centrifugal Pump Impeller—Part II: Stability Analysis

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Eunseok Kim ◽  
Alan Palazzolo
Keyword(s):  
Stability Analysis ◽  
Centrifugal Pump ◽  
Forced Response ◽  
Fe Model ◽  
Pump Impeller ◽  
Rotordynamic Coefficients ◽  
Curve Fit ◽  
Jeffcott Rotor ◽  
Ring Seal ◽  
Rotor Model

In Paper I, some test cases of centrifugal pump impellers which showed unconventional impedances curves were reviewed and possible sources of the bump and dip in the impedance curves were investigated by simulating a wear-ring seal pump impeller. In this paper, the unconventional impedances determined in Paper I are converted into a form for inclusion in rotordynamic stability and forced response analyses. First of all, a finite element (FE) rotor model is considered to investigate the influence of the bump and dip in the impedance curves on the rotordynamic stability. With the same FE model, speed-dependent impedances are calculated to obtain unbalance frequency response. Finally, a new linear curve-fit approach is developed to model the fluctuating impedances since the unconventional impedance cannot be expressed by the second-order polynomials with the rotordynamic coefficients (stiffness, damping, and mass). In order to validate the newly developed method, a Jeffcott rotor model with the impeller forces is considered and rotordynamic stability analysis is implemented. The results of the analysis show that the existence of the bump and dip in the impedance curves may further destabilize the rotor system.

Recent Application of Multistage Centrifugal Compressors for Gas Transmission

1975 ◽  
Author(s):  
M. J. Hussain ◽  
H. E. Johnson
Keyword(s):  
High Pressure ◽  
Recent Application ◽  
Centrifugal Compressors ◽  
Multistage Compressor

Multistage compressor parameters are related to recent gas transmission applications having a diversity of requirements, ranging from large flows to high pressure.

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