Research Papers: Gas Turbines: Structures and Dynamics

Design and Calibration of a Full Scale Active Magnetic Bearing Based Test Facility for Investigating Rotordynamic Properties of Turbomachinery Seals in Multiphase Flow

[+] Author and Article Information
Andreas Jauernik Voigt

Lloyd's Register Consulting,
Copenhagen 2900, Denmark;
Department of Mechanical Engineering,
Technical University of Denmark,
Copenhagen 2800, Denmark
e-mail: andreas.voigt@lr.org

Christian Mandrup-Poulsen

Department of Mechanical Engineering,
Technical University of Denmark,
Copenhagen 2800, Denmark
e-mail: cman@mek.dtu.dk

Kenny Krogh Nielsen

Lloyd's Register Consulting,
Copenhagen 2900, Denmark
e-mail: kenny.krogh-nielsen@lr.org

Ilmar F. Santos

Department of Mechanical Engineering,
Technical University of Denmark,
Copenhagen 2800, Denmark
e-mail: ifs@mek.dtu.dk

1Corresponding author.

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received August 9, 2016; final manuscript received September 15, 2016; published online January 4, 2017. Editor: David Wisler.

J. Eng. Gas Turbines Power 139(5), 052505 (Jan 04, 2017) (10 pages) Paper No: GTP-16-1397; doi: 10.1115/1.4035176 History: Received August 09, 2016; Revised September 15, 2016

The recent move toward subsea oil and gas production brings about a requirement to locate process equipment in deepwater installations. Furthermore, there is a drive toward omitting well stream separation functionality, as this adds complexity and cost to the subsea installation. This in turn leads to technical challenges for the subsea installed pumps and compressors that are now required to handle multiphase flow of varying gas to liquid ratios. This highlights the necessity for a strong research focus on multiphase flow impact on rotordynamic properties and thereby operational stability of the subsea installed rotating machinery. It is well known that careful design of turbomachinery seals, such as interstage and balance piston seals, is pivotal for the performance of pumps and compressors. Consequently, the ability to predict the complex interaction between fluid dynamics and rotordynamics within these seals is key. Numerical tools offering predictive capabilities for turbomachinery seals in multiphase flow are currently being developed and refined, however the lack of experimental data for multiphase seals renders benchmarking and validation impossible. To this end, the Technical University of Denmark and Lloyd's Register Consulting are currently establishing a purpose built state of the art multiphase seal test facility, which is divided into three modules. Module I consists of a full scale active magnetic bearing (AMB) based rotordynamic test bench. The internally designed custom AMBs are equipped with an embedded Hall sensor system enabling high-precision noncontact seal force quantification. Module II is a fully automatized calibration facility for the Hall sensor based force quantification system. Module III consists of the test seal housing assembly. This paper provides details on the design of the novel test facility and the calibration of the Hall sensor system employed to measure AMB forces. Calibration and validation results are presented, along with an uncertainty analysis on the force quantification capabilities.

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Grahic Jump Location
Fig. 1

Test facility in calibration configuration

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Fig. 2

A view of the test facility AMB design showing the embedded Hall sensor placement in a zoom view

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Fig. 3

Section view of AMB showing three main component groups

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Fig. 4

Calibration rig showing pneumatic pistons, grabbing device, and control features

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Fig. 5

Simplified calibration setup showing calibration clamp, single piston with grabber, and force transducer

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Fig. 6

Half part of seal housing assembly showing inlet and outlet features

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Fig. 7

Section view of the center of the inlet cavity showing inlet nozzle distribution and orientation as well as pressure sensor mounting holes

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Fig. 8

Visualization of outlet feature details

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Fig. 9

Horizontal section view of the seal housing assembly

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Fig. 10

AMB stator front view showing electromagnet layout

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Fig. 11

Free-body diagram for the shaft during calibration

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Fig. 12

Flow chart for the automated calibration cycle

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Fig. 13

Examples of force component errors for validation experiments for the two fitting methods. A 8 A bias current and centered shaft. Upward and downward pointing triangles mark increasing and decreasing loads, respectively, (a) constrained fitting—one piston loading (+z), (b) unconstrained fitting—one piston loading (+z), (c) constrained fitting—two piston loading (+y, −z), and (d) unconstrained fitting—two piston loading (+y, −z).

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Fig. 14

Calibration constants for centered shaft at different bias currents

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Fig. 15

Calibration constants at different shaft positions. A 10 A bias current.



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