Turbine Frame Cooling via Bypass Air Scoops
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Solution Overview
Problem
Gas turbine engines face significant thermal stresses in turbine frame assemblies due to rapid temperature changes, which existing cooling systems using compressor air or bore flow do not efficiently address, leading to less efficient engine operation.
Innovation Solution
A turbine frame cooling system that utilizes a bypass air flow through circumferentially-spaced air scoops, first, and second fairings to channel cooling airflow into a cavity, maintaining the temperature of fluid lines below the coking temperature and reducing thermal gradients between struts and the outer ring, thereby simplifying engine design and increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If compressor air or bore flow is used to cool the turbine frame, then the thermal gradients are reduced, but the engine cycle efficiency decreases
Solution Approach 1:
The invention extracts the cooling function from the compressor air system and creates an independent cooling circuit using bypass air. The bypass air is diverted specifically for cooling purposes through air scoops and fairings, separating the cooling function from the main compression system and eliminating the efficiency penalty associated with using compressor air for cooling.
Solution Approach 2:
The bypass air, which is already present in the engine system but not fully utilized, is repurposed for cooling the turbine frame. This multi-functional use of bypass air (both for engine operation and cooling) eliminates the need for dedicated compressor air extraction while maintaining effective cooling.
2Strength
If rigid frame assemblies with radial support struts are used, then structural strength is improved, but thermal stresses increase during transient operation
Solution Approach 1:
The invention applies localized cooling to specific areas of the frame assembly through circumferentially-spaced air scoops and fairings. By directing cooling air to specific locations where thermal gradients are most severe (at the struts and frame connections), the system reduces thermal stresses locally while maintaining the overall rigid structure needed for strength.
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 system effectively reduces thermal stresses and improves engine efficiency by using cooler bypass air, eliminating the need for external air capture and simplifying the engine design, resulting in a lighter and more efficient cooling solution.
Implementation Method 1
The plurality of air scoops extend into a bypass stream and are configured to channel a bypass air cooling flow into the cavity of the outer ring
Implementation Method 2
channeling a first portion of the cooling flow through a plurality of first fairings that are coupled between the outer ring and an inner hub
Data Source
AI summary
A turbine frame cooling system for use with a gas turbine engine includes an outer ring defining a cavity and a hub positioned radially inward of the outer ring. The turbine frame cooling system also includes a plurality of circumferentially-spaced first fairings coupled between the outer ring and the hub and a plurality of circumferentially-spaced second fairings coupled between the outer ring and the hub, wherein the first and second fairings are alternatingly positioned about the hub. The turbine frame cooling system also includes a plurality of circumferentially-spaced air scoops coupled to the outer ring. The plurality of air scoops extend into a bypass stream and are configured to channel a bypass air cooling flow into the cavity of the outer ring.