The Development of Turboexpander-Generators for Gas Pressure Letdown Part I: Design and Analysis

2021 ◽  
Author(s):  
Rasish Khatri ◽  
Jeremy Liu ◽  
Freddie Sarhan ◽  
Ovais Najeeb ◽  
Hiroshi Kajita ◽  
...  
Keyword(s):  
High Speed ◽  
Field Testing ◽  
Magnetic Bearing ◽  
Gas Pressure ◽  
Loop Dynamics ◽  
Full Speed ◽  
Detailed Simulation ◽  
Bearing Design ◽  
Net Load

Abstract This paper describes the design and development of an innovative 280 kW and a 125 kW Turboexpander Generator (TEG) for natural gas pressure letdown (PLD) applications. The flange-to-flange TEG is supported by active magnetic bearings (AMB) and uses an advanced thrust balancing scheme to minimize the net load on the thrust bearing. The machine designs for the two TEG frame sizes are very similar to maintain commonality between parts. A review of the high-speed generator (HSG) and AMB design is provided. A complete AMB closed-loop dynamics study is presented, including a comprehensive rotordynamics and controls analysis. The touchdown bearing design is shown and discussed, and design details of the touchdown bearing resilient mount are presented. The touchdown bearings are given resilience with a tolerance ring. A detailed simulation of a rotor touchdown event at full speed is shown. The magnetic bearing controller (MBC) and variable speed drive (VSD) are located approximately 35 m from the TEG, exposed to the outside environment, and are not required to be explosion-proof. The prototype TEGs are intended to be manufactured and tested in Q1 2021. They will be commissioned, and field tested in Q2 2021. A follow-up paper detailing the mechanical testing and field testing of the units will follow in 2022.

Diesel Engine Turbocharger Stabilized With Novel Tilting Pad Bearing Design

2012 ◽  
Author(s):  
R. Gordon Kirk ◽  
Matthew Enniss ◽  
Daniel Freeman ◽  
Andrew Brethwaite
Keyword(s):  
High Speed ◽  
Fluid Film ◽  
Pressure Pulsations ◽  
The Past ◽  
Fluid Film Bearings ◽  
Film Instability ◽  
Tilting Pad ◽  
Full Speed ◽  
Bearing Design ◽  
Engine Testing

Many high speed turbochargers operate with limit cycle vibration as a result of fluid-film instability. This problem has been under investigation for the past seven years. Only now has a turbocharger with fluid film bearings been run to full speed and loaded, with essentially no bearing induced sub-synchronous vibration. The goal of this research was to have a stable synchronous response with a minimum of non-synchronous contribution excited only by the engine dynamics and exhaust pressure pulsations. Previous papers have documented experimental results of the fixed geometry bearing designs. This paper documents a new, modified tilting pad bearing concept that has replaced the fixed geometry bushings with minimal modifications to the stock bearing housing. The summary of the on-engine testing over the past year is documented in this paper.

Test Results and Analytical Predictions for Rotor Drop Testing of an Active Magnetic Bearing Expander/Generator

2006 ◽  
Vol 129 (2) ◽  
pp. 522-529 ◽  
Author(s):  
Lawrence Hawkins ◽  
Alexei Filatov ◽  
Shamim Imani ◽  
Darren Prosser
Keyword(s):  
High Speed ◽  
High Performance ◽  
Time History ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Test Results ◽  
Direct Drive ◽  
Flow Loop ◽  
Low Loss ◽  
Full Speed

A cryogenic gas expander system that incorporates a high-performance, high-speed permanent magnet, direct-drive generator and low loss magnetic bearings is described. Flow loop testing to 30,000rpm was completed at the system manufacturer’s facility in January 2005, and field installation is scheduled for October 2005. As part of the system testing, the rotor was dropped onto the backup bearings multiple times at an intermediate speed and at 30,000rpm. Orbit and time-history data from a full speed drop and spin down are presented and discussed in detail. A transient, nonlinear rotordynamic analysis simulation model was developed for the machine to provide insight into the dynamic behavior. The model includes the dead band clearance, the flexible backup bearing support, and hard stop. Model predictions are discussed relative to the test data.

scholarly journals Stiffness Enhancement of a Superconducting Magnetic Bearing Using Shaped YBCO Bulks

2019 ◽  
Author(s):  
James Storey ◽  
Mathieu Szmigiel ◽  
Fergus Robinson ◽  
Stuart C. Wimbush ◽  
Rod Badcock
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Magnetic Levitation ◽  
Levitation Force ◽  
Lateral Force ◽  
Magnetic Bearing ◽  
Restoring Forces ◽  
Bearing Design ◽  
Lateral Displacements ◽  
Stiffness Characteristics

High-speed superconducting motors and generators<br>stand to benefit from superconductor magnetic levitation bearings if their stiffness characteristics can be improved. Here we investigate a novel thrust bearing geometry, comprising a conical frustum shaped permanent magnet and matching superconducting toroid and puck assembly, aimed at producing high stiffness coupled with high levitation force. To this end, we have constructed a bearing test rig enabling measurements of the levitation force and stiffness of the assembly of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-d</sub> melt-textured bulks and Nd<sub>2</sub>Fe<sub>14</sub>B permanent magnet at temperatures down to 47 K. The experimental results are supported by finite element modeling that is validated against the experiment, and used to quantify the advantages of this configuration over a conventional cylindrical magnet and HTS puck arrangement.<br>For axial displacements, the assembly produces higher and more consistent stiffness together with stronger restoring forces. For lateral displacements, the assembly produces up to double the lateral force and up to four times the stiffness. Our study also shows that the force contribution to the assembly from the small inner puck is negligible and it can therefore be eliminated from the bearing design.

Magnetic Bearing Design for a High Speed Rotor

1989 ◽  
pp. 137-146 ◽  
Author(s):  
E. H. Maslen ◽  
P. E. Allaire ◽  
M. A. Scott ◽  
P. Hermann
Keyword(s):  
High Speed ◽  
Magnetic Bearing ◽  
Bearing Design

scholarly journals Stiffness Enhancement of a Superconducting Magnetic Bearing Using Shaped YBCO Bulks

2021 ◽  
Author(s):  
James Storey ◽  
M Szmigiel ◽  
F Robinson ◽  
Stuart Wimbush ◽  
Rodney Badcock
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Magnetic Levitation ◽  
Levitation Force ◽  
Lateral Force ◽  
Magnetic Bearing ◽  
Restoring Forces ◽  
Bearing Design ◽  
Lateral Displacements ◽  
Stiffness Characteristics

© 2002-2011 IEEE. High-speed superconducting motors and generators stand to benefit from superconductor magnetic levitation bearings if their stiffness characteristics can be improved. Here we investigate a novel thrust bearing geometry, comprising a conical frustum shaped permanent magnet and matching superconducting toroid and puck assembly, aimed at producing high stiffness coupled with high levitation force. To this end, we have constructed a bearing test rig enabling measurements of the levitation force and stiffness of the assembly of YBa_2Cu_3O_{7-\delta } melt-textured bulks and Nd_2Fe_{14}B permanent magnet at temperatures down to 47 K. The experimental results are supported by finite element modeling that is validated against the experiment, and used to quantify the advantages of this configuration over a conventional cylindrical magnet and HTS puck arrangement. For axial displacements, the assembly produces higher and more consistent stiffness together with stronger restoring forces. For lateral displacements, the assembly produces up to double the lateral force and up to four times the stiffness. Our study also shows that the force contribution to the assembly from the small inner puck is negligible and it can therefore be eliminated from the bearing design.

scholarly journals Stiffness Enhancement of a Superconducting Magnetic Bearing Using Shaped YBCO Bulks

2021 ◽  
Author(s):  
James Storey ◽  
M Szmigiel ◽  
F Robinson ◽  
Stuart Wimbush ◽  
Rodney Badcock
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Magnetic Levitation ◽  
Levitation Force ◽  
Lateral Force ◽  
Magnetic Bearing ◽  
Restoring Forces ◽  
Bearing Design ◽  
Lateral Displacements ◽  
Stiffness Characteristics

© 2002-2011 IEEE. High-speed superconducting motors and generators stand to benefit from superconductor magnetic levitation bearings if their stiffness characteristics can be improved. Here we investigate a novel thrust bearing geometry, comprising a conical frustum shaped permanent magnet and matching superconducting toroid and puck assembly, aimed at producing high stiffness coupled with high levitation force. To this end, we have constructed a bearing test rig enabling measurements of the levitation force and stiffness of the assembly of YBa_2Cu_3O_{7-\delta } melt-textured bulks and Nd_2Fe_{14}B permanent magnet at temperatures down to 47 K. The experimental results are supported by finite element modeling that is validated against the experiment, and used to quantify the advantages of this configuration over a conventional cylindrical magnet and HTS puck arrangement. For axial displacements, the assembly produces higher and more consistent stiffness together with stronger restoring forces. For lateral displacements, the assembly produces up to double the lateral force and up to four times the stiffness. Our study also shows that the force contribution to the assembly from the small inner puck is negligible and it can therefore be eliminated from the bearing design.

scholarly journals Stiffness Enhancement of a Superconducting Magnetic Bearing Using Shaped YBCO Bulks

2019 ◽  
Author(s):  
James Storey ◽  
Mathieu Szmigiel ◽  
Fergus Robinson ◽  
Stuart C. Wimbush ◽  
Rod Badcock
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Magnetic Levitation ◽  
Levitation Force ◽  
Lateral Force ◽  
Magnetic Bearing ◽  
Restoring Forces ◽  
Bearing Design ◽  
Lateral Displacements ◽  
Stiffness Characteristics

High-speed superconducting motors and generators<br>stand to benefit from superconductor magnetic levitation bearings if their stiffness characteristics can be improved. Here we investigate a novel thrust bearing geometry, comprising a conical frustum shaped permanent magnet and matching superconducting toroid and puck assembly, aimed at producing high stiffness coupled with high levitation force. To this end, we have constructed a bearing test rig enabling measurements of the levitation force and stiffness of the assembly of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-d</sub> melt-textured bulks and Nd<sub>2</sub>Fe<sub>14</sub>B permanent magnet at temperatures down to 47 K. The experimental results are supported by finite element modeling that is validated against the experiment, and used to quantify the advantages of this configuration over a conventional cylindrical magnet and HTS puck arrangement.<br>For axial displacements, the assembly produces higher and more consistent stiffness together with stronger restoring forces. For lateral displacements, the assembly produces up to double the lateral force and up to four times the stiffness. Our study also shows that the force contribution to the assembly from the small inner puck is negligible and it can therefore be eliminated from the bearing design.

Endoscopy-assisted removal of periorbital inclusion cysts in children

2011 ◽  
Vol 7 (2) ◽  
pp. 161-164 ◽  
Author(s):  
George Chater-Cure ◽  
Caitlin Hoffman ◽  
Jared Knopman ◽  
Samuel Rhee ◽  
Mark M. Souweidane
Keyword(s):  
High Speed ◽  
Complete Removal ◽  
Skin Incision ◽  
Clinical Findings ◽  
Complete Excision ◽  
Alternative Approach ◽  
Cyst Recurrence ◽  
Scalp Incision ◽  
Access Technique

Object Surgical treatment for periorbital inclusion cysts typically involves a brow, pterional, or partial bicoronal scalp incision for sufficient exposure. The authors have recently employed an endoscopy-assisted technique as an alternative approach intended to minimize the length of the skin incision and avoid scarring in the brow. Methods Children having typical clinical findings of a dermoid cyst located on the hairless forehead were selected to undergo endoscopy-assisted cyst removal. For suspected intradiploic lesions, MR imaging was used to assess osseous involvement. After induction of general anesthesia, a 1–2-cm curvilinear incision was made posterior to the hairline. A 30°-angled endoscope (4 mm) was then used for dissection in the subgaleal compartment. Subgaleal dissection was followed by a circumferential periosteal incision in which the authors used an angled needle-tip unipolar cautery. For lesions within the diploe, a high-speed air drill was used to expose the lesion. Complete removal was accomplished with curettage of either the skull or dural surface. Results Eight patients (5–33 months of age) underwent outpatient endoscopic resection. Seven cysts were extracranial, and 1 cyst extended through the inner table. In all patients complete excision of the cyst was achieved. There was negligible blood loss, no dural violation, and no postoperative infection. There have been no recurrences at a mean follow-up of 15 months. Conclusions Endoscopy-assisted resection of inclusion cysts of the scalp and calvaria is a safe and effective surgical approach. The technique results in negligible incisions with less apparent scarring compared with previously described incisions. This limited-access technique does not appear to be associated with a higher incidence of cyst recurrence.

scholarly journals Three-Axis Inductive Displacement Sensor Using Phase-Sensitive Digital Signal Processing for Industrial Magnetic Bearing Applications

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 115
Author(s):  
Teemu Sillanpää ◽  
Alexander Smirnov ◽  
Pekko Jaatinen ◽  
Jouni Vuojolainen ◽  
Niko Nevaranta ◽  
...  
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Eddy Current ◽  
High Speed ◽  
Digital Signal ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Sensor Design ◽  
Quadrature Demodulation ◽  
Displacement Sensors

Non-contact rotor position sensors are an essential part of control systems in magnetically suspended high-speed drives. In typical active magnetic bearing (AMB) levitated high-speed machine applications, the displacement of the rotor in the mechanical air gap is measured with commercially available eddy current-based displacement sensors. The aim of this paper is to propose a robust and compact three-dimensional position sensor that can measure the rotor displacement of an AMB system in both the radial and axial directions. The paper presents a sensor design utilizing only a single unified sensor stator and a single shared rotor mounted target piece surface to achieve the measurement of all three measurement axes. The sensor uses an inductive measuring principle to sense the air gap between the sensor stator and rotor piece, which makes it robust to surface variations of the sensing target. Combined with the sensor design, a state of the art fully digital signal processing chain utilizing synchronous in-phase and quadrature demodulation is presented. The feasibility of the proposed sensor design is verified in a closed-loop control application utilizing a 350-kW, 15,000-r/min high-speed industrial induction machine with magnetic bearing suspension. The inductive sensor provides an alternative solution to commercial eddy current displacement sensors. It meets the application requirements and has a robust construction utilizing conventional electrical steel lamination stacks and copper winding.

Sign in / Sign up

Export Citation Format

Share Document