Improving the Design of a High Pressure Casing With the Help of Finite Element Analysis to Ensure the Rotor Dynamic Stability of a High Pressure Centrifugal Compressor Equipped With a Hole Pattern Seal

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Yves Bidaut ◽  
Urs Baumann
Keyword(s):  
High Pressure ◽  
Dynamic Instability ◽  
Operating Conditions ◽  
Element Analysis ◽  
History Of ◽  
The Stability ◽  
Discharge Pressure ◽  
Rotor Dynamic ◽  
Full Pressure ◽  
Stability Measurements

This paper focuses on the casing geometry of high pressure compressors. It is common practice to use damper seals, typically the hole pattern type, at the balance piston to ensure the stability of the compressor when compressing fluids with high density levels. Special attention must be paid to the clearance of the hole pattern seal, which must be kept convergent at all operating conditions because a clearance divergence can lead to a rotor dynamic instability of the compressor. Furthermore, the clearance must be kept as low as possible to reduce the leakage losses through the balance piston. Therefore, extensive fine element analyses are performed to determine the mechanical casing deflections in operation and hence, the correct clearance behavior of such damper seals. This paper discusses the history of the casing design during the last 10 years and compares the configurations with respect to the clearance distribution along the damper seal length. To validate the analytical predictions, leakage and stability measurements (using a magnetic shaker) are performed for these high pressure compressors during the full-load, full-pressure testing. This paper presents the stability measurements carried out on two compressors (390 bars and 655 bars discharge pressure) and compares the results.

Improving the Design of a High Pressure Casing With the Help of Finite Element Analysis to Ensure the Rotor Dynamic Stability of a High Pressure Centrifugal Compressor Equipped With a Hole Pattern Seal

2010 ◽  
Author(s):  
Yves Bidaut ◽  
Urs Baumann
Keyword(s):  
High Pressure ◽  
Dynamic Instability ◽  
Operating Conditions ◽  
Element Analysis ◽  
History Of ◽  
The Stability ◽  
Discharge Pressure ◽  
Rotor Dynamic ◽  
Full Pressure ◽  
Stability Measurements

This paper focuses on the casing geometry of High Pressure Compressors. It is common practice to use damper seals, typically the hole pattern type, at the balance piston to ensure the stability of the compressor when compressing fluids with high density levels. Special attention must be paid to the clearance of the hole pattern seal which must be kept convergent at all operating conditions because a clearance divergence can lead to a rotor dynamic instability of the compressor. Furthermore, the clearance must be kept as low as possible to reduce the leakage losses through the balance piston. Therefore, extensive Fine Element Analyses are performed to determine the mechanical casing deflections in operation and hence, the correct clearance behaviour of such damper seals. This paper discusses the history of the casing design during the last ten years and compares the configurations with respect to the clearance distribution along the damper seal length. To validate the analytical predictions, leakage and stability measurements (using a magnetic shaker) are performed for these high pressure compressors during the full-load, full-pressure testing. This paper presents the stability measurements carried out on two compressors (390 bar and 655 bar discharge pressure) and compares the results.

Stability Analysis and Testing of a Train of Centrifugal Compressors for High Pressure Gas Injection

1999 ◽  
Vol 121 (3) ◽  
pp. 509-514 ◽  
Author(s):  
E. A. Memmott
Keyword(s):  
High Pressure ◽  
Stability Analysis ◽  
Gas Injection ◽  
Tilting Pad ◽  
Class 1 ◽  
String Test ◽  
Discharge Pressure ◽  
Three Body ◽  
Rotor Dynamic ◽  
Full Pressure

This paper describes the rotor dynamic stability analysis and the PTC-10 Class 1 test of a three body centrifugal compressor train for high pressure natural gas injection service. This train had a full load full pressure string test on hydrocarbon gasses to a final discharge pressure of 500 BAR (7250 PSIA). Each compressor is of the back to back configuration, and is equipped with tilting pad seals, damper bearings, and a honeycomb labyrinth at the division wall with shunt holes. The driver is a gas turbine.

Stability Analysis and Testing of a Train of Centrifugal Compressors for High Pressure Gas Injection

1998 ◽  
Author(s):  
Edmund A. Memmott
Keyword(s):  
High Pressure ◽  
Stability Analysis ◽  
Gas Injection ◽  
Tilting Pad ◽  
Class 1 ◽  
String Test ◽  
Discharge Pressure ◽  
Three Body ◽  
Rotor Dynamic ◽  
Full Pressure

This paper describes the rotor dynamic stability analysis and the PTC-10 Class 1 test of a three body centrifugal compressor train for high pressure natural gas injection service. This train had a full load full pressure string test on hydrocarbon gasses to a final discharge pressure of 500 BAR (7250 PSIA). Each compressor is of the back to back configuration, and is equipped with tilting pad seats, damper bearings, and a honeycomb labyrinth at the division wall with shunt holes. The driver is a gas turbine.

Numerical Characterization of Swirl Brakes for High Pressure Centrifugal Compressors

2013 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Mirko Micio ◽  
Antonio Andreini ◽  
Bruno Facchini ◽  
Luca Innocenti ◽  
...  
Keyword(s):  
High Pressure ◽  
Tangential Velocity ◽  
Operating Conditions ◽  
Design Parameters ◽  
Centrifugal Compressors ◽  
Labyrinth Seals ◽  
Numerical Characterization ◽  
Lean Angle ◽  
The Stability ◽  
The Many

High pressure centrifugal compressors continue to experience vibrations due to rotordynamic stability. The main cause for aero-induced exciting forces that affects the stability, is the tangential velocity component of the gas entering the many labyrinth seals throughout the machine. In order to control or limit these swirling flows, swirl brakes are generally implemented both at the impeller eye seals and at the balance piston or division wall seal of a centrifugal compressor. This paper deals with the aerodynamic characterization, by means of CFD, of such kind of devices. Several design parameters, such as teeth lean, angle of attack and pitch-to-chord ratio have been considered and also the operating conditions (pressure level and swirl at the swirl brake inlet) are accounted for. This paper aims to improve the physical understanding of the fluid flow of centrifugal compressors swirl brakes allowing an optimization of such systems.

Seal and Bearing Upgrade for Eliminating Rotor Instability Vibration in a High Pressure Natural Gas Compressor

2002 ◽  
Author(s):  
Jiming Li ◽  
Pranabesh De Choudhury ◽  
Rogerio Tacques
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Labyrinth Seal ◽  
Vibration Data ◽  
High Pressure Compressor ◽  
Vibration Model ◽  
Full Speed ◽  
Discharge Pressure ◽  
Full Pressure ◽  
Pressure Compressor

Reported in this paper are the field rotor instability and vibration elimination experienced recently on a compressor train installed on an offshore platform for natural gas service. The compressor train consists of a low-pressure compressor and a high-pressure compressor, which is driven by a gas turbine through a gearbox. The compressor train is rated at a maximum continuous speed of 12,054 rpm. During its first commissioning, a high subsynchronous vibration showed up on the high-pressure compressor when it was put on load at full speed. The high-pressure compressor has nine stages, which are arranged back-to-back in two sections. The high-pressure compressor is rated at a discharge pressure of 176.5 bar (2,560 psia). Field vibration data were analyzed and compared to the rotordynamic results from the lateral vibration model of the rotor. The root of the subsynchronous vibration was identified to be the destabilizing aerodynamic excitation generated mainly by the intermediate seal and the impellers. To eliminate the subsynchronous vibration, a gas pocket damper seal was designed specially to replace the existing intermediate labyrinth seal. Meanwhile, the existing tilt-pad bearings were replaced with the deflection pivot bearings to further improve the rotordynamic performance. The compressor was tested with the new center seal and journal bearings at full load, full pressure, and full speed. The subsynchronous vibration was eliminated. Now the compressor train operates smoothly at its design conditions and the vibration readings remain low and stable.

Dynamic instability characteristics of doubly curved panels subjected to partially distributed follower edge loading with damping

2004 ◽  
Vol 218 (1) ◽  
pp. 67-81 ◽  
Author(s):  
L Ravi Kumar ◽  
P K Datta ◽  
D L Prabhakara
Keyword(s):  
Shear Deformation ◽  
Dynamic Instability ◽  
Shear Deformation Theory ◽  
Structural Damping ◽  
Element Analysis ◽  
Equivalent Viscous Damping ◽  
Direction Control ◽  
The Stability ◽  
Doubly Curved ◽  
Curved Panels

The vibration and dynamic instability characteristics of doubly curved panels subjected to partially distributed non-conservative follower load are studied using finite element analysis. The first-order shear deformation theory is used to model the doubly curved panels, considering the effects of shear deformation and rotary inertia. The theory used is the extension of dynamic, shear deformable theory according to Sander's first approximation for doubly curved shells, which can be reduced to Love's and Donnell's theories by means of tracers. The modal transformation technique is applied to the resulting equilibrium equation for subsequent analysis. Structural damping is introduced into the system in terms of equivalent viscous damping. The effects of load bandwidth, boundary condition, load direction control parameter and damping are considered for the stability behaviour of the panels. The results show that the load bandwidth has a significant effect on the dynamic instability characteristics of the panels. The analysis also shows that, under follower loading, the system is susceptible to instability due to flutter alone or due to both flutter and divergence, depending upon the system parameters. Structural damping significantly affects the critical flutter loads of the panels.

Reliable Rotor Dynamic Design of High-Pressure Compressors Based on Test Rig Data1

2000 ◽  
Vol 123 (4) ◽  
pp. 849-856 ◽  
Author(s):  
N. G. Wagner
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Labyrinth Seal ◽  
Test Results ◽  
Test Rig ◽  
Overall Design ◽  
Comprehensive Test ◽  
Scale Test ◽  
Discharge Pressure ◽  
Rotor Dynamic

The overall design of high-pressure centrifugal compressors is largely influenced by rotordynamic aspects. Rotor instability may restrict operating speed and/or maximum discharge pressure if the destabilizing effects have not been considered accurately during the design phase. A test rig for high pressures has been designed and operated successfully in order to achieve dynamic labyrinth seal coefficients through simulation of original conditions in every aspect. Details are given of the full-scale test rig, which uses active magnetic bearings as a key feature, as well as results from the comprehensive test program. Later on, these results are employed for the design of a compressor for very high pressures, demonstrating the complexity of this design task. Validation of the labyrinth test data and the rotor dynamic analysis is provided by the results from a PTC 10 class I test on a reinjection compressor. During shop testing, this machine has been run with and without swirl brakes and the test results agree very well with the predictions.

An Introduction to the ASME HPS Section 6000 “Hazardous Release Protection”: Historical Development of a Means to Reduce Risk From Pressure Systems Failure

2003 ◽  
Author(s):  
Samuel J. Brown
Keyword(s):  
High Pressure ◽  
Pressure Vessel ◽  
Biological Effects ◽  
Radiant Heat ◽  
Operating Conditions ◽  
Performance Criteria ◽  
Pressure System ◽  
Safety Issues ◽  
History Of ◽  
The 19Th Century

The history of the ASME Boiler and Pressure Vessel Codes and Standards tells us that they were a response in 1915 by the ASME to reduce the numerous explosive failures in the 19th Century that resulted in personnel injury and death, in addition to extensive property loss. The number and scope of ASME Pressure Vessel and Piping Codes and Standards have been issued to cover various applications and operating conditions as the needs have been identified. In the 1970’s, the subcommittee on high pressure technology of the OAC (Operations Applications Components) committee of the ASME Pressure Vessel and Piping Division petitioned the ASME Codes and Standards Council to form a standards committee to prepare a High Pressure Systems Standard that addresses the establishment of a performance criteria and protection criteria for the pressure system. A risk based criterion was provided as a basis for determining if the system design application (siting) exceeds or needs improved reliability for the safety of personnel. The Section 6000 (as well as Sections 1000 to 5000) was begun with a draft outline in 1981 and approved in 2002. Section 6000 “Hazardous Release Protection” of the HPS standard provides a risk based criterion to assess the pressure system internal and external kinetic energy and degenerative hazards and permits a number of ways to lower risk to personnel and structures (e.g., redesign of the pressure system, protection (reduction of consequences), improved inspection (reduction of event probability), etc.). The types of hazards considered are: pressure waves, missiles, foundation motion, radiant heat/fireballs, fire, biological effects, chemical effects, and ionizing radiation. This paper briefly examines: the history of the development of Section 6000, the motivating safety issues, the scope and intent of the various paragraphs of the ASME Section 6000 of the High Pressure System (HPS) standard, its relationship to Sections 1000 to 5000 of the HPS, and some incidences of system failures which identify a need for guidance regarding tolerable risk, other guidelines, standard and code development, and some references that document its development.

Generalized Model for the Approximation of Coupled Acousto-Mechanical Natural Frequencies in High-Pressure Centrifugal Compressors

2020 ◽  
Author(s):  
Christoph Rocky Heinrich ◽  
Arnold Kühhorn ◽  
Klaus Steff ◽  
Nico Petry
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Natural Frequencies ◽  
Numerical Study ◽  
Operating Conditions ◽  
Centrifugal Compressors ◽  
Element Analysis ◽  
Generalized Model ◽  
Wide Range ◽  
The Impact

Abstract The oil and gas, chemical, and process industries employ centrifugal compressors for a wide range of applications. Due to this, the conditions under which centrifugal compressors have to operate, vary significantly from case to case. Gas pipeline compressors, for example, may feature discharge pressures well over 100 bar. During the last decades, comprehensive research was conducted on the impact of high pressure operating conditions on the vibrational behavior of centrifugal compressors. Nowadays, it is well-known that an increase in gas pressure levels leads to a more pronounced interaction between the side cavities and the impeller, which results in a frequency shift of the acoustic and structural modes. For the safe operation of compressors, it is necessary to predict these coupled natural frequencies accurately. The state-of-the-art approach to achieve this objective is the finite element method. While this technique provides high-quality results, it incurs high computational costs and is, therefore, time-consuming. The authors of the current paper propose a generalized model to overcome this challenge. It uses the uncoupled modes of the impeller and side cavities in a modal superposition to approximate the coupled system's natural frequencies. In this way, the intended design geometries are considered while reducing the computational effort significantly. In a numerical study, the generalized model is applied to different systems of increasing complexity, and the results are compared to a finite element analysis. Finally, the paper concludes with a discussion of the limitations and benefits of all employed numerical methods.

Modal Analysis of the Main Frame of Horizontal Type High-Pressure Grouting Machine Based on ANSYS

2012 ◽  
Vol 170-173 ◽  
pp. 3059-3062
Author(s):  
Zhi Cheng Huang ◽  
Ze Lun Li
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Modal Analysis ◽  
Vibration Modes ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Horizontal Type ◽  
Pressure Grouting ◽  
The Stability ◽  
Main Frame

For understanding the dynamic characteristics and improving the stability of the main frame of the horizontal type high-pressure grouting machine, the finite element analysis software ANSYS is applied to the modal analysis of the main frame based on the theory of finite element and vibration mechanics, and the first six natural frequencies and the corresponding vibration modes of the main frame are obtained. The influence of each vibration mode to the working condition of the main frame is analyzed, and provides some reference to improve and enhance the design of the main frame of horizontal type high-pressure grouting machine.

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