Intercooled Cooling Air Valving for Surge-Safe Turbine Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In gas turbine engines, there is a need to efficiently utilize air delivered to the compressor while maintaining high efficiency, especially with increasing fuel prices and the introduction of gear reduction systems that alter air distribution, requiring innovative methods to manage cooling air distribution effectively.
Innovation Solution
A system that taps compressed air upstream of the main compressor section, passes it through a heat exchanger, and directs it to a cooling compressor, which is connected to rotate at a proportional speed, with a valve system that selectively blocks or dumps air to rotatable components based on pressure thresholds, using a combination of check and dump valves to manage airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling air is continuously delivered to rotatable components, then cooling effectiveness is improved, but air utilization efficiency deteriorates during low power operations
Solution Approach 1:
The valve system dynamically adjusts cooling air delivery based on operating conditions. The check valve responds to pressure differential changes between the cooling compressor outlet and the second tap location, automatically opening or closing to dump excess cooling air during low power operations when pressure downstream of the cooling compressor falls below a predetermined limit, thereby preventing waste of compressed air while ensuring continuous cooling capability when needed.
2Reliability
If a check valve blocks flow during low pressure conditions, then surge conditions are prevented, but cooling air delivery is restricted
Solution Approach 1:
The cooling air system is segmented into multiple sources: a first tap upstream of the cooling compressor for normal operation, and a second tap downstream for backup cooling capability. When the check valve blocks flow from the first tap during low pressure conditions, the second tap remains available to selectively deliver cooling air to rotatable components, ensuring continuous cooling protection while preventing surge conditions.
3Productivity
If a gear reduction system is introduced to increase bypass ratio, then propulsion efficiency is improved, but air distribution control becomes more complex
Solution Approach 1:
The valve system operates autonomously based on pressure differential signals from the system itself. The check valve automatically opens or closes in response to pressure changes downstream of the cooling compressor without requiring external control systems, sensors, or actuators. This self-regulating mechanism manages the complex air distribution requirements introduced by the gear reduction system while maintaining propulsion efficiency benefits.
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 solution enhances air utilization efficiency by selectively delivering cooling air to rotatable components, preventing undesirable pressure ratios and surge conditions during lower power operations, while also providing a method to dump air during low demand, thereby optimizing engine performance and reducing fuel consumption.
Implementation Method 1
passes it through a heat exchanger
Implementation Method 2
A valve system includes a check valve for selectively blocking flow downstream of the cooling compressor
Data Source
AI summary
A gas turbine engine includes a main compressor section having a downstream most location, and a turbine section, with both the main compressor section and the turbine section housing rotatable components. A first tap taps air compressed by the main compressor section at an upstream location upstream of the downstream most location. The first tap passes through a heat exchanger, and to a cooling compressor. Air downstream of the cooling compressor is selectively connected to reach at least one of the rotatable components. The cooling compressor is connected to rotate at a speed proportional to a rotational speed in one of the main compressor section and the turbine section. A valve system includes a check valve for selectively blocking flow downstream of the cooling compressor from reaching the at least one rotatable component. A dump valve selectively dumps air downstream of the cooling compressor. A method is also disclosed.