Objective
There is a trend towards greater electrification in aircraft (more electric aircraft), with many of the traditional hydraulic and pneumatic systems being replaced with equivalent electrical systems. The current generation of small civil engines extracts electrical power from a generator located on the auxiliary gearbox via a take-off shaft. This project aims to attach the generator directly to the engine shaft; this will require a smaller sized generator size and will therefore need to be more power dense. To reach the required power density in the future, permanent magnet based embedded machines will likely be required and these must be able to tolerate the demanding hostile environments within the aero engine.
This project will develop an asymmetric embedded generator prototype for medium gas turbine engines or similar platforms. One application on aerospace gas turbine will be achieved by developing engine architecture that uses segmental embedded electrical machine. It will be beneficial to reduce the volume, cost, and improve torque density and system efficiency of gas turbine by replacing mechanical gears with gearless Low Pressure (LP) segmental LP generator.
Project Summary
In this report the detail design of high speed electrical machines directly embedded on the low pressure shaft of the gas turbine engine is carried out, which includes electromagnetic theoretical design, FEM simulation, optimization, mechanical verifications, cooling design and thermal CFD simulation of different segmented flux switching machines and switch reluctance machines. Design process is performed fully taking the challenges such as space envelope limitation, mechanical limitation on the rotor, high temperature affordability and large airgap requirement into account. With the given of Low Pressure Shaft Generator specifications and the available space, the overall comparison is tabulated for their suitability for meeting the stringent requirements of embedded machines in aerospace applications. Our work is a combination of the following research :
(a) Electromagnetic theoretical design, FEM simulation
(b) Mechanical design and FEM simulation;
(c) Cooling system design and thermal CFD simulation;
(d) Power converter and control algorithm development