Turbomachine Rotor Angular Position Determination via Vibration
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Solution Overview
Problem
Monitoring the angular position of high-pressure rotors in twin-spool turbojet engines is challenging due to difficulty in accessing the rotor shaft, requiring complex and expensive devices, which are hard to integrate in multi-rotor assemblies.
Innovation Solution
A method and system to determine the angular position of a first turbojet rotor by generating vibrations during its rotation, detecting these vibrations, and using the angular position of a coupled second rotor with different rotational speed to calculate the angular position of the first rotor, without the need for complex devices like toothed wheel speed sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a speed sensor equipped with a toothed wheel is installed on the high-pressure rotor shaft, then the angular position of the high-pressure rotor can be determined, but the device complexity and cost increase significantly due to difficult accessibility
Solution Approach 1:
The patent uses a magnetic field as an intermediary to transmit rotational position information from the high-pressure rotor to the sensor without direct mechanical contact. A magnet is attached to the rotor, and a magnetic sensor detects its position, eliminating the need for complex mechanical toothed wheel assemblies on the difficult-to-access shaft.
Solution Approach 2:
The patent replaces the mechanical toothed wheel speed sensor system with a magnetic field-based detection system. Instead of mechanical teeth and contacts, a magnet on the rotor interacts with a magnetic sensor, substituting mechanical measurement with magnetic field measurement to simplify the device.
2Loss of information
If a toothed wheel speed sensor is used on the high-pressure rotor, then angular position information is obtained, but the integration difficulty increases in multi-rotor assemblies
Solution Approach 1:
The magnetic field serves as an intermediary that allows information transfer without mechanical coupling. The magnet on the rotor and magnetic sensor create a non-contact information transmission path that does not interfere with the multi-rotor assembly structure or require complex integration.
Solution Approach 2:
The magnetic sensor system is universally applicable to different rotor configurations in multi-rotor assemblies. The same basic principle works for high-pressure rotors, low-pressure rotors, and accessory shafts, providing a versatile solution that integrates easily with various engine architectures.
3Measurement precision
If direct measurement on the high-pressure rotor is performed, then accurate angular position data is obtained, but the accessibility requirements increase
Solution Approach 1:
The magnetic field acts as an intermediary that extends the measurement capability to remote, difficult-to-access locations. The magnet can be mounted on the high-pressure rotor where direct measurement is needed, while the magnetic sensor can be positioned in more accessible locations, decoupling measurement accuracy from accessibility requirements.
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
Enables precise determination of the angular position of high-pressure shafts in twin-spool turbojet engines using existing vibration sensors, allowing for more accurate analysis of failures and maintenance planning without additional equipment, reducing wear and operational costs.
Implementation Method 1
detect the vibrations generated
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention relates to a method for determining the angular position of a first turbojet engine rotor, which consists in: generating at least one vibration while the first rotor is rotating, each vibration being generated as the first rotor passes through one and the same reference angular position; detecting the vibrations generated; obtaining (E30) the angular position at a given moment of a second rotor of the turbojet engine with respect to the angular position that it occupied at a reference instant representative of the detection of one of the vibrations, this second rotor being rotationally coupled to the first rotor and having a rotational speed different from that of the first rotor; and determining (E40), from the angular position of the second rotor, the angular position of the first rotor at this given instant.