Gas turbine engine

Abstract

A gas turbine engine for an aircraft. The engine comprising: an engine core comprising a turbine, a compressor, a fan located upstream of the compressor and comprising a plurality of fan blades, and a core shaft connecting the turbine to the compressor; a gearbox which receives an input from the core shaft and outputs drive, via a driveshaft, to the fan so as to drive the fan at a lower rotational speed than the turbine, the drive shaft and core shaft forming a shaft system. The shaft system provides: a first portion which extends forward from a first thrust bearing to the fan, the first thrust bearing supporting the shaft system and being located between the turbine and the gearbox, and a second portion extending rearward from the first thrust bearing to the turbine, such that in the event of a shaft break within the second portion of the shaft system, said shaft break dividing the shaft system into a front portion axially located by the first thrust bearing and a rear portion no longer axially located by the first thrust bearing, the rear portion is free to move axially rearwardly under a gas load; and wherein the engine further comprises a shaft break detector, configured to detect a shaft break in the shaft system.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This specification is based upon and claims the benefit of priority from UK Patent Application Number 1914042.5 filed on 30 Sep. 2019, the entire contents of which are incorporated herein by reference.BACKGROUNDField of the Disclosure[0002]The present disclosure relates to a gas turbine engine, and particularly a gas turbine engine for use in an aircraft.Background of the Related Art[0003]Modern gas turbine engines typically have up to three compressor-turbine groups, also referred to as spools, connected by respective concentric shafts. These compressor-turbine groups are responsible for the compression and expansion of air passing through the engine.[0004]For example, the Rolls-Royce Trent 1000 aerospace gas turbine engine has three compressor-turbine groups: the low pressure compressor-turbine group, the intermediate pressure compressor-turbine group, and the high pressure compressor-turbine group. Each of these has a corresponding com...

AI Technical Summary

Benefits of technology

The patent describes a gas turbine engine design that reduces the risk of shaft breakage, which can cause damage to the engine. The design also reduces the maximum speed of the turbine, which reduces the risk of failure in the shaft system. Additionally, the design includes a coupling that helps to reduce the strain on the bearings and wear between the bearing races. These technical effects improve the reliability and durability of the gas turbine engine.

Problems solved by technology

This breakage in the shaft leads to an instantaneous decoupling between the turbine and its respective compressor.

As a result the compressor may decelerate rapidly, as it is no longer being driven by the turbine, and the turbine may accelerate rapidly, as it no longer driving the compressor.

The rapid acceleration of the turbine is particularly concerning, as over-speed events can lead to disintegration of the turbine, including possibly bursting of the turbine disc, and further damage to the gas turbine engine.

The turbine connected to this rear portion will inherently have a lower terminal speed due to friction (e.g. clashing or tangling between the turbine blades and any stationary features of the gas turbine engine) and a loss of turbine efficiency (as it moves relative to any guide vanes and blade tip seals).

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