Rotor loss optimization and comprehensive analysis of high-speed magnetic levitation turbine generator

2020 ◽  
Vol 63 (1) ◽  
pp. 63-79
Author(s):  
Tian-yu Gao ◽  
Jin Zhou ◽  
Ya-wei Zheng ◽  
Yuanping Xu
Keyword(s):  
High Speed ◽  
Magnetic Levitation ◽  
Comprehensive Analysis ◽  
Turbine Generator ◽  
Rotor Loss

scholarly journals Reverse Thrust Aerodynamics of Variable Pitch Fans

2018 ◽  
Author(s):  
Tim S. Williams ◽  
Cesare A. Hall
Keyword(s):  
High Speed ◽  
Pressure Ratio ◽  
Test Case ◽  
Suction Surface ◽  
Flow Angle ◽  
Variable Pitch ◽  
Open Rotor ◽  
Weight Penalty ◽  
Reverse Thrust ◽  
Rotor Loss

Variable pitch fans are of interest for future low pressure ratio fan systems since they provide improved operability relative to fixed pitch fans. If they can also be re-pitched such that they generate sufficient reverse thrust they could eliminate the engine drag and weight penalty associated with bypass duct thrust reversers. This paper sets out to understand the details of the 3D fan stage flow field in reverse thrust operation. The study uses the Advanced Ducted Propulsor variable pitch fan test case, which has a design fan pressure ratio of 1.29. Comparison with spanwise probe measurements show that the computational approach is valid for examining the variation of loss and work in the rotor in forward thrust. The method is then extended to a reverse thrust configuration using an extended domain and appropriate boundary conditions. Computations, run at two rotor stagger settings, show that the spanwise variation in relative flow angle onto the rotor aligns poorly to the rotor inlet metal angle. This leads to two dominant rotor loss sources: one at the tip associated with positive incidence, and the second caused by negative incidence at lower span fractions. The second loss is reduced by opening the rotor stagger setting, and the first increases with rotor suction surface Mach number. The higher mass flow at more open rotor settings provide higher gross thrust, up to 49% of the forward take-off value, but is limited by the increased loss at high speed.

scholarly journals THE ANALYSIS OF LOCAL OSCILLATION IN THE GAS TURBINE GENERATOR CONNECTTO POWER GRID SYSTEMS USE LINEAR OBSERVER

2020 ◽  
Vol 5 (2) ◽  
pp. 159-169
Author(s):  
Nguyen Hoang Mai ◽  
Tran van Dung
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Power Plants ◽  
Power Grid ◽  
Low Frequency ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Turbine Generator ◽  
Local Oscillation ◽  
Linear Observer

The low frequency oscillation in the electrical generator connect to power grid is an important problem to control systems, especially in the gas turbine generators with high speed. The oscillation makes affect to life time, finance of operating and effect of energy process. There are many cause of the oscillation in governor speed control of power plants. They use PSS to do damping low frequency oscillation in recently [11], [12], [13], [14], [22], [23]. So PSS usually does process with delay cycle time, therefore it makes effect isn’t good result. This paper presents a method using linear in the gas turbine generator, which connects to power grid. By observe affect action of local oscillation of the power, study finds key point of oscillation time. From that, we take out decision to do prediction of damping in system and supply signal in to PSS to reduce damaging of this oscillation. Simulation results explain difference action of the system with linear observer and system without linear observer.

scholarly journals The Concept of Development and Implementation of High-Speed Transport

2020 ◽  
Vol 18 (1) ◽  
pp. 58-72
Author(s):  
V. M. Alexeev ◽  
A. V. Vaganov ◽  
M. V. Katina
Keyword(s):  
High Speed ◽  
Magnetic Levitation ◽  
Transport Systems ◽  
Rolling Stock ◽  
Design Elements ◽  
Safety Issues ◽  
Current Collection ◽  
High Speeds ◽  
Technical Solutions ◽  
Original Approach

The article discusses the issues of implementation and organization of high-speed transport. The objective of the article is to consider possible options for implementing highspeed (HS) motion systems using the principle of magnetic levitation, which will ensure high speeds for delivery of goods and carrying people over long distances. To achieve this objective, it is necessary to develop an engine and technical solutions for design of HS rolling stock, make decisions on energy supply infrastructure and the HS track, address safety issues and new control systems considering the state of the infrastructure and its design elements. The article discusses several options for implementation of high-speed transport systems, differing in the power supply system, current collection and track based on the magnetic levitation approach. An original approach is proposed in implementation of magnetic levitation transport using the technology of electromagnetic guns designed to implement traction forces of a magnetic levitation vehicle. The advantage of this approach is that it opens the possibility of maneuvering for the vehicle while driving. This allows to abandon switch turnouts, now significantly limiting the use of magnetic levitation transport. A mathematical model describing interaction of an electromagnetic gun and supermagnets located on the track is considered. In constructing the model, methods of the theory of electromagnetic field and interaction of magnetic bodies were used, and when constructing a model of interaction of rolling stock with a magnetic track, methods of mathematical algebra and the Cauchy theorem were used. The article discusses various principles of organization of movement using the magnetic levitation for urban, suburban, and intercity transport.

Three-dimensional simulation of thermal field for a high-speed turbine generator

2013 ◽  
Vol 84 (9) ◽  
pp. 487-491
Author(s):  
V. N. Antipov ◽  
I. Yu. Kruchinina ◽  
A. D. Grozov
Keyword(s):  
High Speed ◽  
Thermal Field ◽  
Three Dimensional ◽  
Turbine Generator ◽  
Dimensional Simulation

Refined Performance Results on a Slowed Mach-Scaled Rotor at High Advance Ratios

2020 ◽  
Vol 65 (1) ◽  
pp. 1-13
Author(s):  
Xing Wang ◽  
Lauren Trollinger ◽  
Inderjit Chopra
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Reverse Flow ◽  
Flow Region ◽  
Comprehensive Analysis ◽  
Compressibility Effect ◽  
Inflow Condition ◽  
Advance Ratio ◽  
Slowed Rotor ◽  
Performance Results

Owing to its ability to alleviate the compressibility effect on the advancing side, the slowed rotor operating at high advance ratios is a key feature in high-speed compound rotorcraft. A series of wind tunnel tests were conducted in the Glenn L. Martin Wind Tunnel with a four-bladed Mach-scaled articulated rotor. The objective of the tests was to gain a basic understanding of unique features of high-advance-ratio aerodynamic phenomena, such as thrust reversal and dynamic stall in the reverse flow region. In this study, high-advance-ratio tests were carried out with highly similar, noninstrumented blades and on-hub control angle measurements, to minimize possible error due to blade structural dissimilarity and pitch angle discrepancy. The tests were conducted at 900 and 1200 RPM, advance ratios of 0.3–0.9, and a shaft tilt study was conducted at±4°. Pitch and flap motion at the blade roots, rotor performance, and vibratory hub loads were investigated during the test. The test data were then compared with those of previous tests and with predictions from comprehensive analysis. The airload results were investigated using comprehensive analysis to gain insights into the influences of advance ratio and shaft tilt angle on rotor performance and hub vibratory loads. Results indicate that the thrust benefit from backward shaft tilt is dependent on the change in the inflow condition and the induced angle of attack increment, and the reverse flow region at high advance ratios is the major contributor to changes in shaft torque and horizontal force.

Performance Evaluation of Magnetohydrodynamic Bearing

2005 ◽  
Author(s):  
H. Hirani ◽  
P. Samanta
Keyword(s):  
High Speed ◽  
Permanent Magnets ◽  
Magnetic Levitation ◽  
Hydrodynamic Lubrication ◽  
Low Cost ◽  
Low Friction ◽  
Oil Flow ◽  
Hybrid Bearing ◽  
Commercial Applications ◽  
Structural Simplicity

The present paper introduces a concept of hydrodynamic-permanent-magnetic hybrid bearing. The hybrid bearing uses repulsive force between permanent magnets and fluid force developed due to relative speed in a single assembly arrangement. Repulsive type passive magnetic levitation has advantage of minimum starting torque. Hydrodynamic lubrication mechanism has advantage of low friction at medium and high speed. This hybridization will be an attractive choice in commercial applications for its low cost, structural-simplicity and no metal-to-metal contact. An experimental setup is designed and developed to investigate the performance characteristics of proposed concept of hybrid bearing. Minimum film thickness, oil flow rate, and temperature rise are recorded at various speed- and load- conditions. Results are plotted to demonstrate the behavior of hybrid bearing arrangement.

scholarly journals Comprehensive Analysis on Heterogeneous Wireless Network in High-Speed Scenarios

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yuyang Zhang ◽  
Tao Zheng ◽  
Ping Dong ◽  
Hongbin Luo ◽  
Zhibo Pang
Keyword(s):  
Wireless Network ◽  
Heterogeneous Network ◽  
High Speed ◽  
Schedule Algorithm ◽  
Good Choice ◽  
Comprehensive Analysis ◽  
Low Latency ◽  
High Bandwidth ◽  
Network Quality ◽  
Stable Network

Greater demands are being placed on the access bandwidth, stability, and delay of network because of the quickening rhythm of life and work, especially in mobile scenario. In order to obtain a stable network with low latency and high bandwidth in mobile scenario, taking advantage of the wireless heterogeneous network in parallel is a good choice. Nowadays, people are increasingly concerned about the network quality under the mobile scenario. Some scholars have done the relevant measurements. However, all of those measurements mainly investigate part of the network parameters or part of mobile scenarios. In this paper, we make the following contributions. Firstly, in high-speed mobile scenario, the wireless network qualities of different vendors are measured synthetically. Secondly, we analyze the benefits of taking advantage of the different vendors. Thirdly, we deploy the replication link mechanism in high-speed mobile scenario and propose an algorithm to remove the duplicate packet in high-speed mobile scenario. And the algorithm can also be used in another multipath schedule algorithm to improve the reliability.

Sign in / Sign up

Export Citation Format

Share Document