Turbomachine Wheel Position Control via Magnetic Sensing
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Solution Overview
Problem
In rotating turbomachines with magnetic bearings, the position control of turbomachine wheels relative to adjacent shrouds is challenging due to dynamic effects, thermal expansions, and fluid pressure changes, as existing position sensors on the rotating element do not account for positional changes not directly measured.
Innovation Solution
A sensor is placed proximate to the turbomachine wheel to measure the blade tips, generating a position signal that a controller uses to adjust the position of the rotor via magnetic actuators, ensuring accurate control of the blade tips' position relative to the shroud surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position sensors are placed on the rotating element to measure rotor position, then the rotor position can be controlled, but the positional changes of the turbomachine wheel that are not carried through to the sensor location are not accounted for
Solution Approach 1:
A magnetic coupling system acts as an intermediary between the rotating blade tips and the stationary sensor. The magnetic field transmits positional information from the rotating element to the stationary sensor without requiring direct mechanical connection, allowing accurate blade tip position measurement while avoiding the limitations of direct mounting on the rotating element.
Solution Approach 2:
The patent replaces direct mechanical sensing on the rotating element with a magnetic field-based sensing system. Instead of mechanically mounting sensors on the rotating blade tips, magnetic coupling transmits positional information through the magnetic field to stationary sensors, eliminating the need for mechanical connections to rotating parts.
2Reliability
If magnetic bearings are controlled to maintain turbomachine wheel position, then positional control is achieved, but dynamic effects, thermal expansions, and fluid pressure changes cause positional deviations
Solution Approach 1:
The system continuously measures blade tip position using magnetic coupling and feeds this information back to the magnetic bearing control system. The controller adjusts the magnetic bearing forces in real-time based on the measured deviations from the desired blade tip clearance, compensating for dynamic effects, thermal expansions, and fluid pressure changes.
Solution Approach 2:
The control system dynamically adjusts the magnetic bearing forces in response to changing operating conditions. Rather than using fixed positioning, the system continuously adapts to maintain optimal blade tip clearance despite varying thermal, dynamic, and pressure conditions.
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 effectively compensates for dynamic and thermal fluctuations, maintaining precise positional control of the turbomachine wheel's blade tips relative to the shroud, enhancing operational efficiency and seal integrity.
Implementation Method 1
A turbomachine is provided with magnetic actuators that support a rotor to rotate about a rotational axis
Data Source
AI summary
A machine includes a rotor supported to rotate about a rotational axis and an actuator arranged to act on the rotor and control a position of the rotor about the rotational axis. A bladed turbomachine wheel is coupled to the rotor and has blade tips that pass closely to an adjacent, non-rotating surface. A sensor is adjacent to the turbomachine wheel and arranged to sense the blade tips and output a position signal representative of the position of blade tips relative to the sensor. A controller is coupled to the sensor and the actuator and is adapted to receive the position signal from the sensor and generate and send a control signal to the actuator to control the position of the rotor based on the position signal from the sensor.