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 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.

Automated Modal Parameter Estimation for Coupled Rotor-Foundation Systems Using Seal Forces as Excitation Source

“…The modules carrying the motor, drive shaft, active magnetic bearings, and seal geometries are situated on a bed plate. The test facility is presented in detail in [26]. The investigation presented in this work focuses mainly on the identification of vibration patterns present in the bed plate of the test facility when the seal inlet pressure changes as described in Table 1.…”

Design of Active Magnetic Bearing Controllers for Rotors Subjected to Gas Seal Forces

“…A method for identification of uncertain/unknown seal and electromechanical parameters, to obtain a precise global model of an AMB-rotor-seal test facility is presented in [30]. The test facility is described in [31]. The method can be employed on-site without the use of any calibrated force measurement sensors -only the free-free model of the shaft is needed a-priori.…”

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.…”