Waveguide Thrust Bearing Sensing for Turbomachine Cross-Over Control
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Solution Overview
Problem
Conventional gas turbine engines face issues with thrust cross-over conditions in thrust bearings, leading to unloaded ball bearings, altered seal clearances, and reduced bearing stiffness, which can cause skidding damage and affect rotor dynamics.
Innovation Solution
A rotor thrust balancing system using waveguide sensors to measure and correct for thrust cross-over conditions, allowing for smaller and lighter thrust bearings by maintaining rotor thrust near zero, and utilizing a closed-loop control system to adjust thrust cavity pressures to prevent cross-over.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the thrust bearing is designed to handle unidirectional thrust loads, then the bearing can support the thrust, but the bearing becomes oversized and overweight
Solution Approach 1:
The patent applies dynamics by making the thrust bearing capable of handling bidirectional thrust loads through a design that allows the bearing to adapt to changing thrust directions. The bearing structure enables it to function effectively whether thrust is applied in the forward or aft direction, eliminating the need for oversized unidirectional bearings.
Solution Approach 2:
The patent changes the operational parameters of the thrust bearing by allowing it to operate with thrust loads in both forward and aft directions. This parameter change enables the bearing to maintain optimal performance across varying operating conditions without requiring excessive size or weight to compensate for unidirectional limitations.
2Force
If the thrust bearing is designed to handle unidirectional thrust loads, then the bearing can support the thrust, but the bearing size increases
Solution Approach 1:
The thrust bearing is designed with dynamic capability to handle thrust in both forward and aft directions. This dynamic design allows the bearing to maintain adequate thrust support without requiring increased size, as the bearing structure naturally adapts to bidirectional loading conditions.
3Force
If cross-over conditions are not compensated for, then the thrust bearing absorbs thrust, but ball bearings become unloaded leading to reduced radial centering
Solution Approach 1:
The patent implements feedback by using sensors to detect thrust bearing load conditions and providing this information to the control system. The control system then adjusts engine operation to prevent cross-over conditions that would unload the ball bearings, thereby maintaining proper radial centering and stability of the rotor assembly.
Solution Approach 2:
The patent applies preliminary anti-action by using the control system to anticipate and prevent cross-over conditions before they occur. By monitoring thrust bearing loads and adjusting engine parameters in advance, the system prevents the ball bearings from becoming unloaded, thus maintaining radial centering stability.
4Force
If cross-over conditions are not compensated for, then the thrust bearing absorbs thrust, but ball bearings may slip causing skidding damage
Solution Approach 1:
The feedback mechanism detects when thrust bearing loads approach conditions that could cause ball bearing slippage. The control system responds by adjusting engine operation to maintain adequate thrust loading on the bearings, preventing skidding damage and improving bearing reliability.
Solution Approach 2:
The control system provides beforehand cushioning by anticipating conditions that could lead to ball bearing slippage and taking preventive action. By maintaining adequate thrust loading on the bearings through control system adjustments, the system prevents skidding damage before it can occur.
5Force
If cross-over conditions are not compensated for, then the thrust bearing absorbs thrust, but bearing stiffness is reduced affecting rotordynamics
Solution Approach 1:
The feedback system monitors thrust bearing loads and provides information to the control system, which adjusts engine operation to maintain optimal thrust loading. This ensures the bearings operate with adequate stiffness to support rotordynamics requirements while still absorbing thrust loads.
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
Prevents thrust cross-over, ensures proper radial centering of the rotor, maintains effective bearing stiffness, and avoids skidding damage, enabling smaller and lighter thrust bearings while maintaining efficient rotor dynamics.
Implementation Method 1
communicate a vibrational frequency from the thrust bearing
Implementation Method 2
changing the pressure of a thrust cavity in contact with the rotating drive shaft to apply a force
Data Source
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AI summary
Rotor thrust balancing systems 200 for turbomachines and methods of using the same are generally disclosed. For example, a rotor thrust balancing system 200 for a turbomachine, wherein the turbomachine defines a centerline 12 extending the length of the turbomachine. The system 200 includes a rotating drive shaft 31, a thrust bearing 118, and a first waveguide sensor 201. The rotating drive shaft 31 couples a turbine section 29 and a compressor section 23 of the turbomachine. The thrust bearing 118 supports the drive shaft 31 of the turbomachine. The thrust bearing 118 includes a plurality of ball bearings 132, an inner race 128 coupled to the rotating drive shaft 31, and an outer race 130 coupled to a fixed structure. The first waveguide sensor 201 is coupled to the outer race 130 at a first end 204 of the waveguide sensor 201. The waveguide sensor 202 communicates a vibrational frequency from the thrust bearing 118 to a second end 206 of the waveguide sensor 201.