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

Abstract

The recent move towards subsea oil and gas production brings about a requirement to locate process equipment in deepwater installations. Furthermore, there is a drive towards 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 non-contact seal force quantification. Module II is a fully automatised 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.

On-Site Identification of Dynamic Annular Seal Forces in Turbo Machinery Using Active Magnetic Bearings: An Experimental Investigation

“…The global model can for example be used to investigate the performance of the test- x inlet injection nozzle, y inlet cavity,z shaft. The figure is adapted from [24] facility operating at other speeds or seal configurations than the one in-which the model was identified for. Also, analysis of robust stability and performance and the design of robust controllers can be carried out with respect to uncertain system parameters [25].…”

“…Test bench AMB showing the AMB actuator and global reference frames. The figure is adapted from[24].…”

“…x secondary discharge cavity, y discharge cavity,z inlet injection cavity,{ inlet nozzle,| pressure sensor,} seal surface. The figure is adapted from[24].…”

Fault diagnosis of active magnetic bearings based on Gaussian GLRT detector

“…It is designed to enable component level experimental identification of rotordynamic properties of turbomachinery seals subdued to multiphase flow conditions. A detailed description can be found in [17]. Figure 1a shows a CAD rendering providing an overview of the facility and its fundamental elements.…”

Lateral vibration control of a shafting-hull coupled system with electromagnetic bearings

“…7 A variety of controllers for EMBs have been proposed. [8][9][10][11][12][13][14][15] EMBs are mainly used in high-speed centrifugation, 16 flywheel energy storage system 17,18 and turbomachinery, 19,20 etc. For vibration control of rotor-bearing systems, EMBs are commonly used.…”