Labyrinth Seal and Pocket Damper Seal High Pressure Rotordynamic Test Data

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Giuseppe Vannini ◽  
Stefano Cioncolini ◽  
Giuseppe Del Vescovo ◽  
Massimiliano Rovini
Keyword(s):  
High Pressure ◽  
Preliminary Test ◽  
Labyrinth Seal ◽  
Effective Length ◽  
Single Frequency ◽  
Special Focus ◽  
Test Rig ◽  
Speed Increase ◽  
Gas Market ◽  
Stiffness And Damping

The current centrifugal compressor design for the oil & gas market is more and more challenging, and the presence of many competitors is pushing technology towards both a casing size reduction and a rotational speed increase. The first point is leading to an increase in the number of wheels per rotor (to do the same service), and the second point is forcing to cross two or even three rotor modes (hence a higher control of rotor damping is necessary). The two points together are leading to increase the rotor “flexibility ratio” (defined as the ratio between the maximum continuous speed and the first critical speed at infinite support stiffness according to API standard, and finally the rotordynamic stability is very much challenged. The centrifugal compressor's rotordynamic stability is strongly related to the internal seals' dynamic behavior, and for this reason, the authors' company decided several years ago to develop internally a high pressure seal test rig to measure internal seals stiffness and damping. The rig is now in operation, and in a previous paper the authors described its main capabilities, the applied identification procedures, and the preliminary test results captured for a long labyrinth seal (smooth rotor, straight toothed stator) tested up to 200 bar. This paper is intended to show more data for the same long Laby with special focus on some peculiar test as negative preswirl test, single frequency versus multifrequency test, offset versus centered seal test. The negative preswirl test shows a drastic change in the effective damping (from destabilizing to stabilizing) and provides a support in favor of the selection of swirl reversal devices at seals upstream. The multifrequency excitation test approach (based on the concurrent presence of several frequencies not multiples at each other) is compared with a single frequency excitation providing similar results and thus confirming the soundness of the multiple effects linear superimposition assumption. The effect of a static offset (simulating the real position of a rotor inside an annular seal) is also investigated proving that the relevant impact is negligible within the range of eccentricity explored (10% of seal clearance). Moreover, a pocket damper seal (PDS) with the same nominal diameter, clearance, and effective length has been tested (up to 300 bar) and compared with the Laby. As expected, the PDS shows both a higher effective stiffness and damping at the same test conditions, so the promising results already collected in a previous test campaign which was performed on a smaller scale and lower pressure test rig were mostly confirmed with the only exception for the effective damping crossover frequency which was lower than expected.

Labyrinth Seal and Pocket Damper Seal High Pressure Rotordynamic Test Data

2013 ◽  
Author(s):  
Giuseppe Vannini ◽  
Stefano Cioncolini ◽  
Giuseppe Del Vescovo ◽  
Massimiliano Rovini
Keyword(s):  
High Pressure ◽  
Preliminary Test ◽  
Labyrinth Seal ◽  
Effective Length ◽  
Single Frequency ◽  
Special Focus ◽  
Test Rig ◽  
Speed Increase ◽  
Frequency Excitation ◽  
Stiffness And Damping

The current centrifugal compressor design for the Oil & Gas market is more and more challenging, and the presence of many competitors is pushing technology towards both a casing size reduction and a rotational speed increase. The first point is leading to an increase in the number of wheels per rotor (to do the same service), and the second point is forcing to cross two or even three rotor modes (hence a higher control of rotor damping is necessary). The two points together are leading to increase the rotor “Flexibility Ratio” (defined as the ratio between the Maximum Continuous Speed and the first critical speed at infinite support stiffness according to [1]), and finally the rotordynamic stability is very much challenged. The centrifugal compressors rotordynamic stability is strongly related to the internal seals’ dynamic behaviour, and for this reason, the authors’ company decided several years ago to develop internally a High Pressure Seal Test Rig [2] to measure internal seals stiffness and damping. The rig is now in operation, and in a previous paper the authors described its main capabilities, the applied identification procedures and the preliminary test results captured for a long Labyrinth seal (smooth rotor, straight toothed stator) tested up to 200bar. This paper is intended to show more data for the same long Laby with special focus on some peculiar test as: • Negative preswirl test • Single frequency vs. Multi-frequency test • Offset vs. Centered Seal test The negative preswirl test shows a drastic change in the effective damping (from destabilizing to stabilizing) and provides a support in favor of the selection of swirl reversal devices at seals upstream. The multi-frequency excitation test approach (based on the concurrent presence of several frequencies not multiples at each other) is compared with a single frequency excitation providing similar results and thus confirming the soundness of the multiple effects linear superimposition assumption. The effect of a static offset (simulating the real position of a rotor inside an annular seal) is also investigated proving that the relevant impact is negligible within the range of eccentricity explored (10% of seal clearance). Moreover, a Pocket Damper Seal (PDS) with the same nominal diameter, clearance and effective length has been tested (up to 300bar) and compared with the Laby. As expected, the PDS shows both a higher effective stiffness and damping at the same test conditions, so the promising results already collected in a previous test campaign which was performed on a smaller scale and lower pressure test rig [3] were mostly confirmed with the only exception for the effective damping cross-over frequency which was lower than expected.

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.

scholarly journals Reliable Rotor Dynamic Design of High-Pressure Compressors Based on Test Rig Data

1999 ◽  
Author(s):  
Norbert 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 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.

Rotordynamic Coefficients of Labseals for Turbines: Comparing CFD Results With Experimental Data on a Comb-Grooved Labyrinth

2005 ◽  
Author(s):  
Joachim Schettel ◽  
Martin Deckner ◽  
Klaus Kwanka ◽  
Bernd Lu¨neburg ◽  
Rainer Nordmann
Keyword(s):  
Stokes Equations ◽  
Labyrinth Seal ◽  
Navier Stokes ◽  
Test Rig ◽  
Navier Stokes Equations ◽  
Detailed Model ◽  
Identification Methods ◽  
Rotating Speed ◽  
Flow Models ◽  
Rotordynamic Coefficients

The main goal of this paper is to improve identification methods for rotordynamic coefficients of labseals for turbines. This aim was achieved in joint effort of the Technische Universita¨t Mu¨nchen, working on experimental identification methods for rotordynamic coefficients, the University of Technology, Darmstadt, working on prediction methods, and Siemens AG, realizing the results. The paper focuses on a short comb-grooved labyrinth seal. Short labseals, amongst others the above mentioned comb-grooved labyrinth, were examined. by means of a very accurately measuring test rig. The rotor was brought into statically eccentric positions relative to the stator, in order to measure the circumferential pressure distribution as a function of pressure, rotating speed and entrance swirl. The data collected were used to validate results obtained with a numerical method. The theoretical approach is based on a commercial CFD tool, which solves the Navier Stokes equations using numerical methods. As a result, a detailed model of the flow within the test rig is produced. The efforts of computation here are greater than when compared with the likewise wide-spread Bulk flow models, however improved accuracy and flexibility is expected. As the validation of the model is successful, it could then be used to gain further insight in the flow within the seal, and to understand the results better. This showed that rotordynamic coefficients of labseals gained from different test rigs are not necessarily comparable.

TAP Project

2004 ◽  
Author(s):  
Carlo Maria Spinelli ◽  
Furio Marchersani
Keyword(s):  
High Pressure ◽  
High Strength Steel ◽  
High Strength ◽  
Innovation Activity ◽  
Long Distance ◽  
Gas Network ◽  
Research And Innovation ◽  
Gas Market ◽  
High Pressure Pipeline ◽  
Very High

International gas market development is towards very long transportation distances (3000–6000 km); the only suitable onshore technology to conjugate economics, large amount of gas conveyed and possibility to exploit remote gas fields appears to be the Very High Pressure (P > 14 MPa), Very High Strength Steel (Steel grade X100 API 5L [1] equivalent) option. Eni Group is going to sponsor a 3 years long project, called TAP (Trasporto gas Alta Pressione) [High Pressure gas Transportation] aimed to demonstrate: • economic evaluation; • technology reliability; • real possibility to build Very High Pressure Pipeline. The project itself is framed into five logical areas: • Evaluation of the applicability of alternative technological solution in extreme enterprise; • Technological innovation, mainly within Eni Group; • FEED (Front End Engineering Development) for strategic route gas pipeline and comparison with LNG option; • Demonstrative construction of a High Strength Steel (X80) pipeline section on Snam Rete Gas Network in Italy; • Demonstrative construction of a Very High Strength Steel (X100 API equivalent) provisioning pilot section pipeline. To achieve this object Eni has involved: • Eni Gas & Power Division as Business Developer; • Snamprogetti as Technology Developer; • Aquater, Enidata, Enitecnologie, Saipem, Snam Rete Gas as specific item expertises; • CSM and Universita` di Bergamo as high qualified partners for lab and full scale testing; • Pipe steel makers and coating producers as fundamental partners to develop new solutions. TAP, within Eni Group, is the final step of a long development research and innovation activity started 8 years ago with two explorative “Long distance pipeline High Grade Steel” projects on Very High Strength Steel performances (strength, toughness, weldability) carried out mainly with the support of Snam, Snamprogetti and Saipem. TAP final goal is to collect, transfer, develop all the possible technological solutions to be ready for building “The pipeline network for Very High Pressure Transportation”.

scholarly journals The uncertainty in stiffness and damping of an automotive vehicle’s trim-structure mounts and its effect on the variability of the vibration transfer function

2017 ◽  
Vol 232 (15) ◽  
pp. 2587-2598 ◽  
Author(s):  
Ali Abolfathi ◽  
Dan J O’Boy ◽  
Stephen J Walsh ◽  
Amy M Dowsett ◽  
Stephen A Fisher
Keyword(s):  
Boundary Condition ◽  
Transfer Function ◽  
Dynamic Response ◽  
Transfer Functions ◽  
Effective Stiffness ◽  
3D Printer ◽  
Structural Elements ◽  
Test Rig ◽  
Manufacturing Tolerances ◽  
Stiffness And Damping

A large number of plastic clips are used in an automotive vehicle to connect the trim to the structure. These are small clips with very small masses compared to the structural elements that they connect together; however, the uncertainty in their properties can affect the dynamic response. The uncertainty arises out of their material and manufacturing tolerances and more importantly the boundary conditions. A test rig has been developed that can model the mounting condition of the clips. This allows measurement of the range of their effective stiffness and damping. Initially, the boundary condition at the structure side is replicated. The variability is found to be 7% for stiffness and 8% for damping. In order to simulate the connection of the trim side, a mount is built using a 3D printer. The variability due to the boundary condition on both sides was as large as 40% for stiffness and 36% for damping. A Monte Carlo simulation is used in order to assess the effect of the uncertainty of the clips’ properties on the vibration transfer functions of a door assembly. A simplified connection model is used in this study where only the axial degree of freedom is considered in connecting the trim to the door structure. The uncertainty in the clip stiffness and damping results in a variability in the vibration transfer function which is frequency dependent and can be as high as 10% at the resonant peaks with higher values at some other frequencies. It is shown that the effect of the uncertainty in the clips effective damping is negligible and the variability in the dynamic response is mainly due to the uncertainty in the clip’s stiffness. Furthermore, it is shown that the variability would reduce either by increasing or decreasing the effective stiffness of the clips.

An experimental investigation of a microturbine simulated rotor supported on multileaf gas foil bearings with backing bump foils

2017 ◽  
Vol 232 (9) ◽  
pp. 1169-1180 ◽  
Author(s):  
Bo Zhang ◽  
Shemiao Qi ◽  
Sheng Feng ◽  
Haipeng Geng ◽  
Yanhua Sun ◽  
...  
Keyword(s):  
High Speed ◽  
Preliminary Test ◽  
Journal Bearings ◽  
Rotating Machinery ◽  
System Stability ◽  
Test Rig ◽  
Thrust Bearings ◽  
Foil Bearings ◽  
Simulated System ◽  
First Time

Two multileaf gas foil journal bearings with backing bump foils and one set of gas foil thrust bearings were designed, fabricated, and used in a 100 kW class microturbine simulated rotor system to ensure stability of the system. Meanwhile, a preliminary test rig had been built to verify the simulated system stability. The rotor synchronous and subsynchronous responses were well controlled by using of the gas foil bearings. It is on the multileaf gas foil bearings with backing bump foils that the test was conducted and verified for the first time in open literatures. The success in the experiments shows that the design and fabrication of the rotor and the gas foil bearings can provide a useful guide to the development of the advanced high speed rotating machinery.

Analysis of Traction Characteristics of Grease-Lubricated Sliding Bearing

2013 ◽  
Vol 655-657 ◽  
pp. 640-643
Author(s):  
Bo Yuan Yang ◽  
Xiaofan Yan ◽  
Bing Su
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Room Temperature ◽  
Extreme Pressure ◽  
Test Rig ◽  
Sliding Bearing ◽  
Traction Coefficient ◽  
Lubrication Effect ◽  
Lubricated Sliding

Adopting the test rig of traction characteristics of grease-lubricated sliding bearing, the practical condition of sliding bearing was simulated and the traction coefficient of DGG Grease under different temperature, velocity and load was tested. Besides, the traction characteristics of the grease were also elaborated. The results indicate that the traction coefficient increases when the temperature gradually rises from room temperature while it gradually decreases when the temperature exceeds 85°C. Under the condition of high temperature and high pressure, the extreme pressure additive has obvious effects, the traction coefficient reducing and maintaining constant, so a better lubrication effect is realized.

The Unsteady Flow Field of a Purged High Pressure Turbine Based on Mode Detection

2017 ◽  
Author(s):  
S. Zerobin ◽  
S. Bauinger ◽  
A. Marn ◽  
A. Peters ◽  
F. Heitmeir ◽  
...  
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Unsteady Flow ◽  
Flow Behavior ◽  
Low Pressure ◽  
Pressure Probe ◽  
Special Focus ◽  
High Pressure Turbine ◽  
Low Pressure Turbine ◽  
Mode Detection

This paper presents an experimental study of the unsteady flow field downstream of a high pressure turbine with ejected purge flows, with a special focus on a flow field discussion using the mode detection approach according to the theory of Tyler and Sofrin. Measurements were carried out in a product-representative one and a half stage turbine test setup, which consists of a high-pressure turbine stage followed by an intermediate turbine center frame and a low-pressure turbine vane row. Four independent purge mass flows were injected through the forward and aft cavities of the unshrouded high-pressure turbine rotor. A fast-response pressure probe was used to acquire time-resolved data at the turbine center frame duct inlet and exit. The interactions between the stator, rotor, and turbine center frame duct are identified as spinning modes, propagating in azimuthal direction. Time-space diagrams illustrate the amplitude variation of the detected modes along the span. The composition of the unsteadiness and its major contributors are of interest to determine the role of unsteadiness in the turbine center frame duct loss generation mechanisms and to avoid high levels of blade vibrations in the low-pressure turbine which can in turn result in increased acoustic emissions. This work offers new insight into the unsteady flow behavior downstream of a purged high-pressure turbine and its propagation through an engine-representative turbine center frame duct configuration.

scholarly journals A High Throughput Approach Based on Dynamic High Pressure for the Encapsulation of Active Compounds in Exosomes for Precision Medicine

2021 ◽  
Vol 22 (18) ◽  
pp. 9896
Author(s):  
Eugenia Romano ◽  
Paolo Antonio Netti ◽  
Enza Torino
Keyword(s):  
Cell Culture ◽  
High Pressure ◽  
Culture Media ◽  
Preliminary Test ◽  
Bilayer Membrane ◽  
Microfluidic System ◽  
Culture Model ◽  
Before And After ◽  
Dynamic High Pressure

In recent decades, endogenous nanocarrier-exosomes have received considerable scientific interest as drug delivery systems. The unique proteo-lipid architecture allows the crossing of various natural barriers and protects exosomes cargo from degradation in the bloodstream. However, the presence of this bilayer membrane as well as their endogenous content make loading of exogenous molecules challenging. In the present work, we will investigate how to promote the manipulation of vesicles curvature by a high-pressure microfluidic system as a ground-breaking method for exosomes encapsulation. Exosomes isolated from Uppsala 87 Malignant Glioma (U87-MG) cell culture media were characterized before and after the treatment with high-pressure homogenization. Once their structural and biological stability were validated, we applied this novel method for the encapsulation in the lipidic exosomal bilayer of the chemotherapeutic Irinotecan HCl Trihydrate-CPT 11. Finally, we performed in vitro preliminary test to validate the nanobiointeraction of exosomes, uptake mechanisms, and cytotoxic effect in cell culture model.

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