Interturbine Vane Double-Walled Leading Edge Cooling
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to high secondary air flow consumption for cooling, which affects the engine's overall efficiency and requires optimization of air flow and pressure management.
Innovation Solution
The design incorporates a mid-turbine frame with annular outer and inner cases, load spokes, and an inter-turbine duct with hollow airfoils featuring a double-walled leading edge structure, separate cavities for cooling air, and seal housings to manage cooling air flow efficiently, allowing independent introduction of cooling air into the front chamber and maintaining pressure within the airfoils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling air supply is used to cool the outer duct wall and hollow vanes, then adequate cooling is provided, but secondary air flow consumption is high which reduces engine cycle efficiency
Solution Approach 1:
The cooling system is segmented into multiple independent air chambers (front chamber, rear chamber, inner front cavity, outer front cavity) that can be cooled by separate air flows. This allows optimized distribution of cooling air to different thermal zones, reducing overall secondary air consumption while maintaining adequate cooling effectiveness for each segment.
Solution Approach 2:
Different regions of the interturbine vane are provided with differentiated cooling arrangements. The front chamber (with double-walled leading edge) receives cooling air from the inner front cavity, while the rear chamber receives cooling air from the outer front cavity. This localized cooling approach optimizes air flow distribution based on specific thermal requirements of each region, reducing total secondary air consumption.
2Loss of energy
If multiple separate cooling air flows are introduced into different chambers, then cooling optimization is achieved, but device complexity increases
Solution Approach 1:
Multiple cooling functions are merged into a single integrated interturbine vane structure. The front and rear chambers are combined within one vane, with seal housings integrating the cooling air distribution system. This consolidation achieves cooling optimization without proportionally increasing overall device complexity, as the complex cooling system is contained within the vane assembly rather than requiring separate external systems.
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 configuration optimizes cooling air usage, reducing energy expenditure while maintaining adequate airflow and pressure, thereby enhancing the gas turbine engine's efficiency and performance.
Implementation Method 1
Cooling air is conventionally supplied to cool the outer duct wall and then enters the core cavity of the respective hollow vanes to cool the same
Implementation Method 2
an annular first seal housing disposed in the first cavity, thereby defining an annular outer front cavity between the first seal housing and an upstream section of the outer duct wall, the outer front cavity being separated from the first cavity
Data Source
AI summary
A gas turbine engine has a mid turbine frame disposed between turbine rotor assemblies. The mid turbine frame includes hollow airfoils radially extending through an annular gas path duct. The airfoils each include a double-walled leading edge structure to define a front chamber separated from a rear chamber defined in the remaining space within the airfoil.