A Design of Simulation Experiment System for the Helium Turbine

2012 ◽  
Author(s):  
Liang Zhu ◽  
Zhengang Shi
Keyword(s):  
Simulation Experiment ◽  
Cooling System ◽  
Aerodynamic Force ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Radial Load ◽  
Monitoring And Control ◽  
Experiment System ◽  
Compressor Rotor ◽  
Load Simulator

In this paper a new design of simulation experiment system for the helium turbine is described. This experiment system is for to study the rotor dynamic performance of the helium turbine in a 10 MW high temperature reactor-based helium turbine (HTR-10GT) power generation project. The system is a vertical and biaxial arrangement. The motor rotor is on one axis and the turbine-compressor rotor is another axis. The two axes are connected by a gear box having a gear ratio of 1:5 and two couplers. The motor has a rate speed of 3,000rpm, and the turbine-compressor rotor 15,000 rpm. The turbine-compressor rotor, which is simulated, has a mass of 646 kg, a length of 3,568mm, and is supported by two radial magnetic bearings along with an axial magnetic bearing. The design load carrying capacity of the axial magnetic bearing is 9.8 kN with a clearance of 0.7mm and the radial magnetic bearing is 1.96 kN with a clearance of 0.6mm. For simulating the aerodynamic force and the unbalanced force on the turbine-compressor rotor when it was turning, we designed a magnetic load simulator which can exert axial and radial load to the rotor directly. The design axial load of the magnetic load simulator is 10kN and the radial load is 715N both with a clearance of 1mm. The whole simulation experiment system includes the ventilation and cooling system and monitoring and control system. It is the first time that the simulation test has been run for the vertical helium turbine with magnetic bearings, running at full speed. The turbine-compressor rotor will pass through the critical speeds for the first and second order of bending, before reaching the rated speed. The magnetic load simulator can exert load quickly and directly, and the load form can be changed online, which is a new application way for the magnetic bearing.

Design and Evaluation of Hybrid Magnetic Bearings for Turbo Compressors

2018 ◽  
Author(s):  
Cheol Hoon Park ◽  
Jun Young Park ◽  
Eui Soo Yoon
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Cooling System ◽  
High Capacity ◽  
Axial Direction ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Shaft Length ◽  
Compressor Rotor ◽  
Load Tests

Recently, high capacity and high efficiency turbo machines such as turbo blowers and turbo compressors have been being developed. To keep up with this trend, magnetic bearings are increasingly being applied to turbo machines instead of air foil bearings. In this study, a hybrid magnetic bearing composed of a permanent magnet and an electromagnet was applied to 300-HP (horsepower) turbo compressors with rated speeds of 50,000 rpm. The length of the shaft should be reduced as short as possible so that the compressor rotor can rotate stably while maintaining a small vibration at a rotation speed of 50,000 rpm. In this study, the additional shaft length for the axial gap sensor is eliminated by applying a new layout in which the axial gap sensor is placed on the inner surface of the thrust magnetic bearing. No-load tests and full-load tests in the manufactured turbo compressors were performed to evaluate the performance of the designed magnetic bearings. The biggest obstacle to this development is the heat problems caused by compressor impellers and high-speed motors. Thanks to the cooling system using water and air, the problem of thermal expansion of the rotor in the axial direction can be avoided. Thrust forces were estimated using the control current for thrust magnetic bearings. The experiment is also performed to evaluate the vibration of each turbo compressor and the results are presented. Based on the evaluated vibration, it has been confirmed that the hybrid magnetic bearings and the new axial gap sensor layout can support the turbo compressors stably.

Full-Size Rotordynamic Test Rig for Magnetic and Auxiliary Bearing Testing and Initial Results

2012 ◽  
Author(s):  
Oscar De Santiago ◽  
Víctor Solórzano ◽  
Sergio Díaz
Keyword(s):  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Test Rig ◽  
Transient Event ◽  
Electric Motor Drives ◽  
Compressor Rotor ◽  
Rotor Support ◽  
Rotor Stator Interaction ◽  
Auxiliary Bearing ◽  
Floating Platforms

Recent challenges in turbocompresor design include applications in subsea installations as well as remote operation in unmanned floating platforms. These applications benefit from oil-free operation which solves technical hurdles while being environmentally friendly. The most mature oil-free rotor support technology today is the magnetic bearing which is being used by several manufacturers as their standard solution to these advanced applications. These systems require auxiliary bearings to contain the rotor in case of a power failure to the magnetic bearings or a transient event. In general, there exists the need to develop commercial solutions for auxiliary bearings to extend its life, in particular regarding cumulative damage associated to drop events. This paper presents the design of a configurable test rig that can accommodate different rotor sizes, up to 1200 mm in bearing span, and 711 mm diameter wheels. The rig can also accommodate bearing sizes up to 229 mm. Rig pedestals can fit different bearing types such as magnetic bearings and/or auxiliary bearings independently, including oil bearings for comparison purposes. Misalignment and support flexibility effects are also possible. A 15.5 kW, variable speed electric motor drives the test rotor up to a speed limit of 10,000 rpm. Initial experiments on auxiliary bearings are shown for a 5-impeller, 57.8 kg, subcritical compressor rotor without drop events to study the baseline dynamic behavior of roller-element bearings (with inner clearance) on soft supports (o-rings). These experiments are presented to illustrate non-linear vibration regimes present during rotor-stator interaction with a highly unbalanced rotor. Experimental evidence presented can be used to fine-tune current auxiliary bearingmodels to improve rotordynamic predictive codes.

A Design of Magnetic Load Simulator for the Rotor Dropping Protection Experiment System of Helium Circulator in HTR

2014 ◽  
Author(s):  
Zhu Liang ◽  
Wang Hong
Keyword(s):  
High Temperature ◽  
Axial Load ◽  
Magnetic Bearings ◽  
Protection System ◽  
Economic Losses ◽  
Experiment System ◽  
Full Speed ◽  
High Temperature Reactor ◽  
Load Simulator ◽  
The Impact

The rotor of helium circulator in High Temperature Reactor (HTR) is supported by magnetic bearings, but the auxiliary bearings of the magnetic bearings are easy to be broken if the rotor touched down the bearings at the full speed. If the rotor touched down more than a few times, the auxiliary bearings must be changed, which will bring huge economic losses to the HTR. Therefore, we designed a rotor dropping protection system which can reduce the impact when the touching down happened and protect the auxiliary bearings from more damages. We designed an experiment system to validate the reliability of the protection system. For simulating the impact of the auxiliary bearings when the rotor dropped, a magnetic load simulator was designed, which can exert axial load to the motor directly by electromagnetic force though a similar technology to the magnetic bearings. The design axial load of the magnetic load simulator is 110kN with a clearance of 1mm. By analyzing and calculating the parameter of the magnetic load simulator, we thought it can meet the loading requirements of this test. And the design of the magnetic load simulator will open up a new way of application for the magnetic bearings.

scholarly journals A Vibration Sensor-Based Method for Generating the Precise Rotor Orbit Shape with General Notch Filter Method for New Rotor Seal Design Testing and Diagnostics

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5249
Author(s):  
Karel Kalista ◽  
Jindrich Liska ◽  
Jan Jakl
Keyword(s):  
Notch Filter ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Harmonic Vibration ◽  
Filter Method ◽  
Vibration Exciter ◽  
Active Magnetic Bearings ◽  
Rotor Vibration ◽  
Seal Design ◽  
Exact Shape

Verification of the behaviour of new designs of rotor seals is a crucial phase necessary for their use in rotary machines. Therefore, experimental equipment for the verification of properties that have an effect on rotor dynamics is being developed in the test laboratories of the manufacturers of these components all over the world. In order to be able to compare the analytically derived and experimentally identified values of the seal parameters, specific requirements for the rotor vibration pattern during experiments are usually set. The rotor vibration signal must contain the specified dominant components, while the others, usually caused by unbalance, must be attenuated. Technological advances have made it possible to use magnetic bearings in test equipment to support the rotor and as a rotor vibration exciter. Active magnetic bearings allow control of the vibrations of the rotor and generate the desired shape of the rotor orbit. This article presents a solution developed for a real test rig equipped with active magnetic bearings and rotor vibration sensors, which is to be used for testing a new design of rotor seals. Generating the exact shape of the orbit is challenging. The exact shape of the rotor orbit is necessary to compare the experimentally and numerically identified properties of the seal. The generalized notch filter method is used to compensate for the undesired harmonic vibrations. In addition, a novel modified generalized notch filter is introduced, which is used for harmonic vibration generation. The excitation of harmonic vibration of the rotor in an AMB system is generally done by injecting the harmonic current into the control loop of each AMB axis. The motion of the rotor in the AMB axis is coupled, therefore adjustment of the amplitudes and phases of the injected signals may be tedious. The novel general notch filter algorithm achieves the desired harmonic vibration of the rotor automatically. At first, the general notch filter algorithm is simulated and the functionality is confirmed. Finally, an experimental test device with an active magnetic bearing is used for verification of the algorithm. The measured data are presented to demonstrate that this approach can be used for precise rotor orbit shape generation by active magnetic bearings.

scholarly journals Low cost driver device for microclimate maintenance in the pre-milking of dairy cattle

2013 ◽  
Vol 33 (1) ◽  
pp. 01-10 ◽  
Author(s):  
Irenilson M. da Silva ◽  
Héliton Pandorfi ◽  
Ângelo J. S. de Vasconcelos ◽  
Renato Laurenti ◽  
Cristiane Guiselini
Keyword(s):  
Dairy Cattle ◽  
Environmental Control ◽  
Cooling System ◽  
System Development ◽  
Low Cost ◽  
Cost Driver ◽  
Monitoring And Control ◽  
Laboratory Calibration ◽  
Evaporative Cooling System ◽  
And Control

Due to the importance of the environment on animal production and thus environmental control, the study aims to build a system for monitoring and control the meteorological variables, temperature and relative humidity, low cost, which can be associated with an evaporative cooling system (ECS). The system development included all the stages of assembly, test and laboratory calibration, and later the validation of the equipment carried in the field. The validation step showed results which allowed concluding that the system can be safely used in the monitoring of these variables. The controller was efficient in management of the microclimate in the waiting corral and allowed the maintenance of the air temperature within the comfort range for dairy cattle in pre-milking with averaged 25.09 ºC during the afternoon. The equipment showed the lower cost (R$ 325.76) when compared to other middle market (R$ 450.00).

scholarly journals Sliding Mode Output Feedback Control of a Flexible Rotor via Magnetic Bearings

1998 ◽  
Author(s):  
A. S. Lewis ◽  
A. Sinha ◽  
K. W. Wang
Keyword(s):  
Differential Equations ◽  
Sliding Mode ◽  
Output Feedback Control ◽  
Angular Speed ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Control Parameters ◽  
Flexible Rotor ◽  
Rotor Imbalance ◽  
Feedback Algorithm

A sliding mode feedback algorithm is proposed to control the vibration of a flexible rotor supported by magnetic bearings. It is assumed that the number of states is greater than the number of sensors. A mathematical model of the rotor/magnetic bearing system is presented in terms of partial differential equations. These equations are then discretized into a finite number of ordinary differential equations through Galerkin’s method. The sliding mode control law is designed to be robust to rotor imbalance and transient disturbances. A boundary layer is introduced around each sliding hyperplane to eliminate the chattering phenomenon. The results from numerical simulations are presented which not only corroborate the validity of the proposed controller, but also show the effects of various control parameters as a function of the angular speed of the rotor. In addition, results are presented that indicate how the current required by the magnetic bearings is affected by control parameters and the angular speed of the rotor.

scholarly journals Tip Clearance Actuation With Magnetic Bearings for High-Speed Compressor Stall Control

2000 ◽  
Vol 123 (3) ◽  
pp. 464-472 ◽  
Author(s):  
Z. S. Spakovszky ◽  
J. D. Paduano ◽  
R. Larsonneur ◽  
A. Traxler ◽  
M. M. Bright
Keyword(s):  
High Speed ◽  
Design Procedure ◽  
Magnetic Bearing ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Magnetic Bearings ◽  
Test Facility ◽  
Control Analysis ◽  
Servo Actuator ◽  
Stall Control

Magnetic bearings are widely used as active suspension devices in rotating machinery, mainly for active vibration control purposes. The concept of active tip-clearance control suggests a new application of magnetic bearings as servo-actuators to stabilize rotating stall in axial compressors. This paper presents a first-of-a-kind feasibility study of an active stall control experiment with a magnetic bearing servo-actuator in the NASA Glenn high-speed single-stage compressor test facility. Together with CFD and experimental data a two-dimensional, incompressible compressor stability model was used in a stochastic estimation and control analysis to determine the required magnetic bearing performance for compressor stall control. The resulting requirements introduced new challenges to the magnetic bearing actuator design. A magnetic bearing servo-actuator was designed that fulfilled the performance specifications. Control laws were then developed to stabilize the compressor shaft. In a second control loop, a constant gain controller was implemented to stabilize rotating stall. A detailed closed loop simulation at 100 percent corrected design speed resulted in a 2.3 percent reduction of stalling mass flow, which is comparable to results obtained in the same compressor by Weigl et al. (1998. ASME J. Turbomach. 120, 625–636) using unsteady air injection. The design and simulation results presented here establish the viability of magnetic bearings for stall control in aero-engine high-speed compressors. Furthermore, the paper outlines a general design procedure to develop magnetic bearing servo-actuators for high-speed turbomachinery.

Dynamic Modeling and Analysis of Active Magnetic Bearings

2014 ◽  
Vol 494-495 ◽  
pp. 685-688
Author(s):  
Rong Gao ◽  
Gang Luo ◽  
Cong Xun Yan
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Modeling ◽  
Magnetic Bearing ◽  
Integrated System ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Modeling And Analysis ◽  
Amb System ◽  
Mathematics Method

Active magnetic bearing (AMB) system is a complex integrated system including mechanics, electronic and magnetism. In order to research for the basic dynamic characteristic of rotor supported by AMB, it is necessary to present mathematics method. The dynamics formula of AMB is established using theory means of dynamics of rotator and mechanics of vibrations. At the same tine, the running stability of rotor is analyzed and the example is presented in detail.

scholarly journals Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Atsushi Nakajima ◽  
Katsuhiro Hirata ◽  
Noboru Niguchi ◽  
Masayuki Kato
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Active Control ◽  
Dynamic Characteristics ◽  
Negative Pressure ◽  
Axial Direction ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Asymmetric Structure ◽  
Element Analysis

Abstract Supporting forces of magnetic bearings are lower than those of mechanical bearings. In order to solve these problems, this paper proposes a new three-axis active control magnetic bearing (3-axis AMB) with an asymmetric structure where its rotor is attracted only in one axial direction due to a negative pressure of fluid. Our proposed 3-axis AMB can generate a large suspension force in one axial direction due to the asymmetric structure. The performances of our proposed 3-axis AMB are computed through 3-D finite element analysis.

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