Tandem Rotor Blade Cooling for Compressor Heat Management
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Solution Overview
Problem
Gas turbine engines face high temperatures in the turbine and downstream compressor sections, leading to increased stress and reduced component life due to windage heat-up from traditional stator vane stages, which limits the ability to increase pressure ratio and operating temperatures.
Innovation Solution
The implementation of a tandem compressor rotor blade stage that combines two discrete blade stages into a single stage, eliminating the need for an intervening stator vane stage and incorporating a tangential onboard injector (TOBI) for enhanced cooling, using compressor midstream air cooled in a heat exchanger, and sealing mechanisms to direct cooling air effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the overall pressure ratio delivered by the compressor section is increased, then the compressor section delivers higher compression, but the temperature at the downstream end of the compressor section increases
Solution Approach 1:
The patent extracts and removes the intervening stator vane stage from the compressor section. This elimination reduces windage heat-up and allows the downstream compressor rotor blade stage to operate at lower temperatures while maintaining higher pressure ratios, directly resolving the temperature increase problem associated with pressure ratio enhancement
2Stress or pressure
If traditional stator vane stages are used in the compressor section, then the compressor provides necessary compression, but windage heat-up increases component stress and reduces component life
Solution Approach 1:
The patent removes the intervening stator vane stage that causes windage heat-up. This extraction eliminates the source of excessive heating while maintaining compression through the tandem rotor blade stage configuration, thereby reducing thermal stress and extending component life
Solution Approach 2:
The patent combines two discrete blade stages into a single tandem rotor blade stage. This merging eliminates the need for an intervening stator vane stage, reducing windage heat-up and improving component reliability while maintaining the necessary compression function
3Temperature
If cooling air is applied to the downstream compressor rotor blade stage, then operating temperatures can be controlled, but the use of compressor discharge air for cooling reduces the air available for combustion
Solution Approach 1:
The patent applies cooling air to the blade platforms and platforms before the air reaches the combustion chamber. By pre-cooling these components, the system can use cooler air sources (such as compressor discharge air) without compromising combustion performance, as the cooling occurs upstream where high temperatures are not yet required
Solution Approach 2:
The patent applies cooling selectively to specific locations (blade platforms and platforms) where heat generation occurs. This localized cooling approach uses air efficiently by targeting only the areas that require temperature control, minimizing the impact on combustion air availability
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 reduces windage heat-up, increases component life, allows for higher operating temperatures, and enhances pressure ratio while maintaining temperature tolerances, thereby improving the overall efficiency and longevity of engine components.
Implementation Method 1
the compressor midstream air is cooled in a heat exchanger before passing into the TOBI
Implementation Method 2
sealing mechanisms to direct cooling air effectively
Data Source
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AI summary
A gas turbine engine (10) has a compressor section (14) with a downstream most blade stage (24) and a downstream vane row (26) positioned downstream of the downstream most blade stage (24). The downstream most blade stage (24) includes a plurality of blade pairs (53) with the majority of blade pairs (53) being circumferentially spaced apart from others of the blade pairs (53), each the blade pair (53) being operatively connected to a rotor disk (50) disposed radially inward from the blade pairs (53) with each blade pair (53) including a forward blade (52) and an aft blade (54). The aft blades (54) are configured to further condition airflow with respect to the forward blade (52). A tangential onboard injector (TOBI) (202) is positioned radially inwardly of the downstream vane row (26).