Stator Vane Assembly for Gas Turbine Overspeed Protection
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Solution Overview
Problem
Current gas turbine engine designs require oversized turbine discs to prevent transient overspeed events, leading to increased weight and mechanical loading, which is undesirable for reliability and efficiency.
Innovation Solution
A stator vane assembly with pivotally mounted vanes that can be moved by gas flow momentum, eliminating the need for actuators and allowing rapid closure to mitigate overspeed events, featuring a first latching mechanism that releases vanes to block gas flow and a second mechanism to secure them in the closed position, optionally with a damper and actuator for controlled movement and reset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If turbine disc is sized to withstand transient overspeed events, then reliability is improved, but weight increases
Solution Approach 1:
The stator vane assembly is configured to automatically close before the turbine disc reaches dangerous overspeed levels. The vanes pivot from an open position (allowing normal gas flow) to a closed position (blocking gas flow) when overspeed is detected, preventing the disc from accelerating to burst speeds in the first place, thus eliminating the need for oversized disc design
Solution Approach 2:
The stator vane assembly acts as an intermediary safety device between the gas flow and the turbine disc. Instead of making the disc itself more robust, the invention introduces a protective mechanism (the vane assembly) that mediates the energy transfer by blocking gas flow before it can cause dangerous overspeed conditions
2Measurement precision
If conventional actuators are used to move vanes, then control precision is improved, but device complexity and weight increase
Solution Approach 1:
The stator vane assembly uses the kinetic energy of the gas flow itself to actuate the vanes. When gas flow encounters the vanes in their open position, the aerodynamic forces automatically pivot the vanes to the closed position without requiring external actuators. This self-actuating mechanism eliminates complex control systems while maintaining functional effectiveness
Solution Approach 2:
The invention replaces conventional mechanical actuator systems with an aerodynamic actuation mechanism. Instead of using motors, hydraulics, or pneumatics to move the vanes, the system uses the gas flow's own momentum and pressure to pivot the vanes, substituting a simple mechanical pivot for a complex actuator assembly
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
The solution reduces turbine disc weight by allowing rapid and efficient closure of vanes to prevent overspeed, enhancing engine reliability and reducing the risk of disc burst while maintaining safety margins.
Implementation Method 1
The momentum of the gas flow passing through the assembly provides an actuating torque on each of the plurality of vanes to move them from the first arrangement to the second arrangement
Implementation Method 2
a pivot axis of each of the plurality of vanes is offset from the line of aerodynamic centre of pressure of the vane towards a trailing edge of the vane
Data Source
AI summary
Stator vane assembly includes plurality of vanes arranged in circumferential array, radially proximal mounting portion, radially distal mounting portion, and first latching mechanism. Each of plurality of vanes extends radially between radially proximal mounting portion and radially distal mounting portion, with each of plurality of vanes being pivotally mounted between radially proximal mounting portion and radially distal mounting portion. Plurality of vanes is movable between first arrangement allowing gas to flow across vanes, and second arrangement blocking gas flow across vanes. Pivot axis of each of plurality of vanes is offset from the line of aerodynamic center of pressure of vane towards trailing edge of vane, and first latching mechanism holds plurality of vanes in first arrangement. Upon receipt of signal, first latching mechanism releases plurality of vanes so that gas flow through vane assembly causes plurality of vanes to move from first arrangement to second arrangement.