Position sensorless starting of super high-speed PM Generator for micro gas turbine

2006 ◽  
Vol 53 (2) ◽  
pp. 415-420 ◽  
Author(s):  
M. Morimoto ◽  
K. Aiba ◽  
T. Sakurai ◽  
A. Hoshino ◽  
M. Fujiwara
2021 ◽  
pp. 5-17
Author(s):  
Sergey A. GANDZHA ◽  
◽  
Nikolay I. NEUSTROEV ◽  
Pavel A. TARANENKO ◽  
◽  
...  

The modern power industry is characterized by intense development of distributed generation, with which numerous sources of different capacities are connected into a single network. This makes it possible to improve the reliability of the entire system, since the probability of several sources to fail simultaneously is quite low. Electric generation based on high-speed gas turbine units accounts for a significant share in the overall balance, due to which scientific research and new engineering solutions in this area are important and relevant. An innovative design of a high-speed gas turbine unit based on a switched axial generator is proposed. This electrical machine has a diamagnetic armature, which eliminates magnetic losses, due to which better efficiency of the power unit is achieved and its design is simplified. The high speed of rotation and the presence of critical resonant rotor speeds generated the need to adopt appropriate engineering decisions in regard of its supports. A combined suspension involving the use of magnetic and gas-dynamic bearings is proposed. The magnetic bearings support the gas turbine unit operation at low speeds during its acceleration, and the gas-dynamic bearings support its operation at high nominal speed. The generator design and the combined suspension layout are shown. The numerical analyses of magnetic and gas-dynamic bearings for a gas turbine unit for a capacity of 100 kW and rotation speed of 70 000 rpm are given. The study results can be used for a series of gas turbine units with capacities ranging from 10 to 500 kW. In our opinion, this concept is competitive with modern analogs with a radial generator design.


Aerospace ◽  
2019 ◽  
Vol 6 (5) ◽  
pp. 55 ◽  
Author(s):  
James Large ◽  
Apostolos Pesyridis

In this study, the on-going research into the improvement of micro-gas turbine propulsion system performance and the suitability for its application as propulsion systems for small tactical UAVs (<600 kg) is investigated. The study is focused around the concept of converting existing micro turbojet engines into turbofans with the use of a continuously variable gearbox, thus maintaining a single spool configuration and relative design simplicity. This is an effort to reduce the initial engine development cost, whilst improving the propulsive performance. The BMT 120 KS micro turbojet engine is selected for the performance evaluation of the conversion process using the gas turbine performance software GasTurb13. The preliminary design of a matched low-pressure compressor (LPC) for the proposed engine is then performed using meanline calculation methods. According to the analysis that is carried out, an improvement in the converted micro gas turbine engine performance, in terms of thrust and specific fuel consumption is achieved. Furthermore, with the introduction of a CVT gearbox, the fan speed operation may be adjusted independently of the core, allowing an increased thrust generation or better fuel consumption. This therefore enables a wider gamut of operating conditions and enhances the performance and scope of the tactical UAV.


Author(s):  
Peng Shang ◽  
Renjun Zhan ◽  
Ling Xiong ◽  
Yanhua Sun ◽  
Jian Zhou

Author(s):  
Sadanand Kulkarni ◽  
Soniya D. Naik ◽  
K. Sarosh Kumar ◽  
M. Radhakrishna ◽  
Soumendu Jana

Lubricant free high speed turbo-machineries are one of the emerging fields in the gas turbine technology. Foil bearings are the major contenders in the lubricant free bearings due to their ability to support significant loads at very high speeds. The paper deals with the various stages in the development of discrete and continuous bump foil bearings and testing of the same for designed speeds and loads. Development of bumps involves determination of bump geometry for the desired load capacity, design of special purpose dies for the fabrication of corrugated sheets, identification of suitable bump material and evolution of heat treatment process. Here Beryllium–Copper (Be-Cu) is used as a bump material because of its self-lubricating property and good mechanical strength. The clearance between the shaft and top foil can be adjusted by providing the back-up foils between the encircling foil and bump foil. The rotor system simulating the weight of a typical micro gas turbine is designed and fabricated. The foil bearings developed are tested under this simulated load conditions at speeds above 50,000 rpm. The results obtained show that the rotor is completely airborne at speed slightly above 9000 rpm and at higher speeds the rotor is stable.


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