Intercooled Cooling Air Cycle Machine for Gas Turbine Engines
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Solution Overview
Problem
Conventional cooling air methods in gas turbine engines fail to provide sufficient pressure and low enough temperature cooling air to effectively reduce temperatures in the turbine section, exceeding material limits and impacting engine efficiency.
Innovation Solution
An intercooled cooling system with multiple stages, including a first cooling stage that cools bleed air from the compressor and a pump to increase its pressure, followed by a second cooling stage to further cool the air, with a valve system for mixing it with higher-pressure air and delivering it to the turbine section, along with an air cycle machine for pneumatic power and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling air methods are used (tapping air from downstream compressor and passing through heat exchanger), then the system structure is simple, but the cooling air pressure is insufficient and temperature is not low enough to effectively cool turbine sections
Solution Approach 1:
The cooling system is divided into multiple stages: a first cooling stage that cools bleed air from the compressor, a pump to increase pressure, and a second cooling stage that further cools the pressurized air. This segmentation allows each stage to perform a specific function (cooling or pressurizing) to achieve the required cooling air temperature and pressure without excessive overall system complexity
Solution Approach 2:
The first cooling stage performs preliminary cooling of the bleed air before it enters the pump. This preliminary action reduces the temperature of the air before pressurization, improving the overall efficiency of the cooling system and enabling the second cooling stage to achieve the final required temperature more effectively
2Quantity of substance
If cooling air is tapped from the downstream most end of the compressor section, then the air is readily available, but the air temperature is elevated and insufficient for effective turbine cooling
Solution Approach 1:
The first cooling stage performs preliminary cooling of the bleed air immediately after it is tapped from the compressor, reducing its temperature before the air undergoes pressurization. This ensures that the air quantity is maintained while the temperature is reduced to effective levels for turbine cooling
Solution Approach 2:
The pump acts as an intermediary between the first cooling stage and the second cooling stage, pressurizing the cooled air from the first stage and delivering it to the second cooling stage. This intermediary function allows the system to maintain both adequate air quantity and low temperature while achieving the required pressure for effective turbine section cooling
3Productivity
If high temperatures are maintained in the turbine section, then engine efficiency is improved, but material limits are exceeded requiring improved cooling
Solution Approach 1:
The cooling system applies local quality by delivering cooled air specifically to the turbine sections that require cooling, rather than cooling the entire engine uniformly. The multi-stage cooling approach allows different regions of the cooling system to operate at different temperatures and pressures, optimizing cooling effectiveness at the turbine while maintaining engine efficiency
Solution Approach 2:
The system changes the parameters of the cooling air through the multi-stage process: the first cooling stage reduces temperature, the pump increases pressure, and the second cooling stage further reduces temperature. These parameter changes transform the bleed air into an effective cooling medium that can lower turbine section temperatures to within material limits while preserving engine efficiency
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 intercooled cooling system effectively reduces turbine section temperatures, enhancing engine efficiency and operational safety by providing pressurized, cooled air, while also powering aircraft systems and maintaining desired pump speeds.
Implementation Method 1
A first cooling stage of the plurality of cooling stages is fluidly coupled to a bleed port of a compressor of the gas turbine engine to receive and cool bleed air with the air stream
Implementation Method 2
A cooling pump is fluidly coupled to the first cooling stage to receive and increase a pressure of the cool bleed air
Implementation Method 3
A second cooling stage of the plurality of cooling stages is fluidly coupled to the pump to receive and cool the pressurized cool bleed air
Implementation Method 4
the valve selectively delivering air into a mixing chamber where it is mixed with air from a tap that is compressed to a higher pressure than the air from the bleed port
Data Source
AI summary
A first cooling stage is fluidly coupled to a bleed port of a compressor to receive and cool bleed air with the air stream to produce a cool bleed air. A cooling pump receives and increases a pressure of the cool bleed air to produce a pressurized cool bleed air. A second cooling stage is fluidly coupled to the pump to receive and cool the pressurized cool bleed air to produce an intercooled cooling air. A valve is downstream of the first cooling stage, the valve selectively delivering air into a mixing chamber where it is mixed with air from a tap that is compressed to a higher pressure than the air from the bleed port, and the valve also selectively supplying air from the first cooling stage to a use on an aircraft associated with the gas turbine engine. A method is also disclosed.