Turbine Vane Cooling via Segmented Shaft Bore Design
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Solution Overview
Problem
The existing variable area vane arrangements in turbine engines face challenges with increased weight, cost, and complexity due to the large diameter of the outer shaft bore required for sufficient cooling air, which affects the size and efficiency of the bearing.
Innovation Solution
A turbine engine stator vane design featuring a rotatable airfoil with a concave and convex side surface, a cavity, and a flange connected to the second airfoil end, where the flange extends circumferentially around the cavity inlet and radially away from the side surfaces, and a shaft connected to the second airfoil end, which reduces the need for a large bearing by optimizing cooling air distribution and reducing gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the outer shaft bore diameter is increased to provide sufficient cooling air, then the cooling efficiency is improved, but the bearing size and weight increase significantly
Solution Approach 1:
The shaft is divided into two separate shafts: an inner shaft connected to the outer radial stator vane platform and an outer shaft connected to the inner radial stator vane platform. This segmentation allows each shaft to have an optimized bore size for its specific cooling requirements, eliminating the need for a single large-diameter bore that would be required to serve both platforms
Solution Approach 2:
Each shaft is given a locally optimized bore diameter based on its specific cooling air requirements. The inner shaft and outer shaft can have different bore sizes tailored to their respective platforms' cooling needs, rather than using a uniformly large bore throughout the entire shaft structure
2Temperature
If the outer shaft bore diameter is increased to provide sufficient cooling air, then the cooling efficiency is improved, but the device complexity increases
Solution Approach 1:
The cooling air supply system is segmented into two independent pathways through the inner shaft and outer shaft. Each shaft independently delivers cooling air to its respective platform, simplifying the overall system architecture compared to a single large-bore shaft that would require complex internal flow distribution mechanisms
3Quantity of substance
If the bearing size is increased to accommodate a larger shaft bore, then the cooling air capacity is improved, but the cost increases
Solution Approach 1:
The bearing system is segmented into an inner bearing and an outer bearing, each supporting its respective shaft. This allows each bearing to be manufactured at an optimal size for its specific load and cooling air requirements, reducing overall material usage and manufacturing cost compared to a single large bearing
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 design enhances cooling efficiency while minimizing weight and complexity by reducing the size of the bearing and improving gas flow management, thereby optimizing the performance of the turbine engine.
Implementation Method 1
Airfoil cooling apertures may subsequently direct the cooling air out of the cavity to film cool the outer surfaces of the airfoil that are exposed to the core gas
Data Source
AI summary
A turbine engine stator vane is provided that rotates about an axis, and includes an airfoil, a flange and a shaft. The airfoil extends axially between a first airfoil end and a second airfoil end. The airfoil includes a concave side surface, a convex side surface and a cavity. The concave and the convex side surfaces extend between an airfoil leading edge and an airfoil trailing edge. The cavity extends axially into the airfoil from a cavity inlet in an end surface at the second airfoil end. The flange is connected to the second airfoil end. The flange extends circumferentially around at least a portion of the cavity inlet, and radially away from the concave and the convex side surfaces to a distal flange edge. The shaft extends along the axis, and is connected to the second airfoil end.