Retaining Collar Bayonet Mount for Turbine Speed Sensing
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Solution Overview
Problem
Gas turbine engines face challenges in detecting turbine overspeed due to driveshaft fractures, which can lead to uncontainable turbine rotor speeds and potential engine housing breaches, necessitating effective turbine overspeed protection mechanisms.
Innovation Solution
The implementation of an auxiliary wheel with an annular balance land and a speed sensing system, including a probe and controller, to accurately detect the rotational speed of the turbine disc and adjust fuel supply accordingly, along with a retaining collar for secure mounting, enables precise speed monitoring and balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a driveshaft fracture detection system is implemented, then turbine overspeed protection is improved, but device complexity increases
Solution Approach 1:
An auxiliary wheel is introduced as an intermediary component between the turbine disc and the speed sensing system. This auxiliary wheel carries the speed sensor target and is secured to the turbine disc, allowing the magnetic probe to detect rotational speed without directly interfacing with the turbine disc itself. This intermediary approach enables reliable overspeed detection while simplifying the overall system architecture.
2Measurement precision
If an auxiliary wheel with speed sensor target is added to the turbine disc, then measurement precision of turbine speed is improved, but device complexity increases
Solution Approach 1:
The auxiliary wheel serves multiple functions simultaneously: it carries the speed sensor target for precise rotational speed detection, provides a balancing surface for dynamic balancing corrections, and acts as a mechanical interface between the turbine disc and the sensing system. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving precise speed measurement.
Solution Approach 2:
Instead of directly sensing the turbine disc's rotation, the system uses a copy approach by placing a speed sensor target on the auxiliary wheel that rotates synchronously with the turbine disc. The magnetic probe detects the passing of magnetic teeth on this target, providing an accurate representation of the turbine's rotational speed without requiring direct contact or modification of the turbine disc itself.
3Stability of the object's composition
If dynamic balancing corrections are made to the auxiliary wheel, then rotor balance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The auxiliary wheel is designed with a dedicated balance land that is prepared in advance during manufacturing. This balance land provides a predefined surface that can be selectively ground or machined to add or remove material for balancing corrections. By preparing this balance land beforehand, the system enables dynamic balancing adjustments without requiring complex post-assembly modifications, thereby managing manufacturing precision requirements in a controlled manner.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides accurate turbine speed detection and balancing, preventing overspeed conditions and ensuring safe operation by enabling timely fuel adjustments and secure mounting, thus enhancing the safety and reliability of gas turbine engines.
Implementation Method 1
a magnetic probe positioned in proximity to the speed sensor target so that rotation of the shaft carries the plurality of teeth past the probe, said probe being configured to detect the speed of the teeth passing the probe
Implementation Method 2
said body being dimensioned so that the radially outward facing surface frictionally engages the radially inward facing surface of a cylindrical male mounting member in a bayonet mount
Data Source
AI summary
A retaining collar is disclosed for a bayonet mount comprising a rotor disc having a male mounting member defining a pair of apertures and an auxiliary annular wheel defining a plurality of mounting slots. The retaining collar comprises a ring-shaped body and a pair of retention pins. The ring-shaped body has a pair of circumferential end portions separated by a circumferential gap, and an arcuate radial outer surface extending circumferentially between the end portions. The body is dimensioned so that the radial outer surface frictionally engages a radial inner surface of a cylindrical male mounting member in the bayonet mount. The pair of retention pins each extend radially outward from one of the circumferential end portions. Each of the retention pins are dimensioned to extend radially outward from the body through one of said apertures and one of said mounting slots.