Variable Vane Air Bearing for Gas Turbine Friction Reduction
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Solution Overview
Problem
Conventional variable vane systems in gas turbine engines face challenges with high engine temperatures and pressures, which affect the performance and longevity of bearings and bushings, necessitating an improvement in vane systems for optimized airflow and reduced friction.
Innovation Solution
The introduction of a pressurized air supply system that forms air bearings between vane stems and casings, allowing for controlled rotation of vanes with reduced friction and improved temperature resistance, using apertures to connect internal cavities and bearing gaps for air flow and a seal to maintain position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bearings and bushings are used in variable vane systems, then the system can operate under high temperatures and pressures, but the performance and longevity of the bearings and bushings deteriorate
Solution Approach 1:
The patent introduces a pressurized air bearing system where air is supplied through apertures in the vane stem to create an air film between the vane stem and bearing surface. This pneumatic bearing replaces conventional mechanical bearings and bushings, allowing the vane to rotate with minimal friction and contact under high temperature and pressure conditions, thereby resolving the contradiction between reliability and temperature exposure
Solution Approach 2:
The invention substitutes mechanical contact bearings with a non-contact air bearing system. Instead of relying on physical bearings and bushings that suffer from wear and degradation under high temperatures, the system uses pressurized air to create a frictionless interface, replacing the mechanical support system with a pneumatic one that is immune to thermal degradation
2Ease of operation
If conventional mechanical bearings are used, then the vane can rotate, but friction increases under high temperature and pressure conditions
Solution Approach 1:
The pressurized air bearing creates a cushion of air between the vane stem and bearing surface, enabling smooth rotation with minimal friction. The air film acts as a lubricant that eliminates direct mechanical contact, thereby reducing energy loss due to friction while maintaining ease of vane rotation operation
Solution Approach 2:
The pressurized air acts as an intermediary substance between the vane stem and the bearing surface. This air film mediates the interaction between moving and stationary parts, allowing relative motion to occur with minimal friction and energy loss, thereby resolving the contradiction between ease of operation and energy loss
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 enables controlled and low-friction rotation of vanes, enhancing temperature resistance and reducing wear, thus improving the efficiency and durability of variable vane systems under high-pressure conditions.
Implementation Method 1
a pressurized air supply inlet in fluid communication with at least one of the bearing gaps to form a stem air bearing to intermittently float at least one of the vane stems for controlled rotation about the vane axis
Data Source
AI summary
A variable vane system includes an outer platform, an inner casing radially inward from the outer casing and a vane extending between the inner and outer casings defining a vane axis. An inner vane stem is engaged with the inner casing and an outer vane stem is engaged with the outer casing. The system includes a bearing gap defined radially with respect to the vane axis between each of the inner and outer casings and respective vane stems for allowing the vane to rotate about the vane axis for varying angle of attack. The system includes a pressurized air supply inlet in fluid communication with at least one of the bearing gaps to form a stem air bearing to intermittently float at least one of the vane stems for controlled rotation about the vane axis.