Rotational Imbalance Reduction via Pulsed Heating

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Solution Overview

Problem

Conventional methods for reducing rotational imbalances in turbomachine rotors are inadequate, as imbalances can arise or change during operation due to factors like thermal heating, coil shifts, and blade erosion, which cannot be effectively compensated by existing balancing techniques.

Innovation Solution

A rotational imbalance reduction apparatus featuring a heating element, a pulsing element, and a control system that synchronizes heat application with the rotor's frequency of rotation to induce eddy currents and create a bending moment, rebalancing the rotor by applying heat in pulses at specific intervals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional balancing techniques are used to adjust rotor weight, then initial rotational imbalance is reduced, but the rotor becomes imbalanced again during operation due to thermal heating, coil shifts, and blade erosion

Engineering Contradiction:
Improverotor balance stabilityVSAvoidcompensation capability for operational changes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system transitions from static balancing (fixed weight adjustment) to dynamic balancing (continuous real-time adjustment). The control system continuously monitors rotor imbalance during operation and dynamically adjusts the heating element activation to compensate for changing thermal, mechanical, and erosional conditions, maintaining balance stability throughout the operational lifecycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rotor balancing system becomes self-regulating through automatic feedback control. The control system uses vibration sensors to detect imbalance conditions and automatically activates the heating element to induce eddy currents that generate corrective bending moments, enabling the system to self-correct without external intervention during operation.

Inventive Principle:
Principle #25Self-service

2Reliability

If heating elements are mechanically connected to the rotating device for continuous heat application, then thermal expansion can be controlled, but mechanical complexity and potential interference with rotation increase

Engineering Contradiction:
Improvethermal balance controlVSAvoidmechanical connection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical connection and contact-based heating with electromagnetic induction. The heating element is electromagnetically coupled to the rotor through an air gap, eliminating mechanical connections while maintaining effective thermal control. This substitution reduces mechanical complexity, eliminates wear and interference issues, and enables non-contact heat application for reliable thermal balance control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If continuous heat is applied to the rotor location, then thermal expansion can counteract imbalance, but excessive thermal stress and energy consumption occur

Engineering Contradiction:
Improveimbalance compensationVSAvoidenergy consumption for heating
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system uses periodic pulsed heating instead of continuous heat application. The control system activates the heating element in synchronized pulses with the rotor rotation frequency, applying heat only when needed to induce corrective bending moments. This periodic action maintains effective imbalance compensation while significantly reducing overall energy consumption and thermal stress accumulation in the rotor structure.

Inventive Principle:
Principle #19Periodic action

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

Effectively reduces rotational imbalances and radial vibration amplitudes by dynamically adjusting heat application to counteract thermal expansion and other operational-induced imbalances, enhancing rotor stability and efficiency.

Implementation Method 1

A rotational imbalance reduction apparatus features a heating element, a pulsing element, and a control system that synchronizes heat application with the rotor's frequency of rotation to induce eddy currents and create a bending moment

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

induce eddy currents and create a bending moment, rebalancing the rotor by applying heat in pulses at specific intervals

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

dynamically adjusting heat application to counteract thermal expansion and other operational-induced imbalances

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3301257B1Rotational imbalance reduction
Publication Date: 2019.06.12 GENERAL ELECTRIC CO
  • EP3301257B1 patent drawingFigure 1
  • EP3301257B1 patent drawingFigure 2
  • EP3301257B1 patent drawingFigure 3

AI summary

Various embodiments include apparatuses and systems for controlling rotational imbalance of a rotary element (338, 638, 838, 938). In one embodiment, a rotational imbalance reduction apparatus (204, 424, 624, 824) includes at least one heating element (418) for heating a location (226, 926) on a rotary element (338, 638, 838, 938), a pulsing element (330, 430, 630, 730, 830, 930) configured to pulse actuate the heating element (418) in synchronization with a multiple, fraction, or mixed fraction of the frequency of rotation of the rotary element (338, 638, 838, 938), and a control system (216, 316, 416, 616, 716, 816) coupled with the pulsing element (330, 430, 630, 730, 830, 930) and the heating element (418), the control system (216, 316, 416, 616, 716, 816) actuating the heating element (418) and the pulsing element (330, 430, 630, 730, 830, 930) to apply heat to the location (226, 926) of the rotary element (338, 638, 838, 938) in pulses synchronized with the multiple, fraction, or mixed fraction of the frequency of rotation of the rotary element (338, 638, 838, 938).