Dual-Tap Compressor Bleed Air System for Aircraft
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Solution Overview
Problem
The existing gas turbine engine systems face inefficiencies due to high-pressure and high-temperature compressed air being tapped from the high-pressure compressor, leading to fuel loss and increased complexity in mid-turbine duct design, as the air needs to be cooled and pressure-lowered for aircraft use, which also heats the fan air used for propulsion.
Innovation Solution
A dual-tap system is introduced, with a low-pressure tap and a high-pressure tap, selectively communicating with an air handling system to supply air based on operational conditions, allowing for efficient air distribution and bypass cooling, reducing the load on the mid-turbine duct and simplifying its design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-pressure compressor air is tapped for aircraft use, then air supply for cabin and pressurization is ensured, but the air requires cooling and pressure reduction which causes energy loss and fuel consumption increase
Solution Approach 1:
The system dynamically selects between high-pressure and low-pressure compressor taps based on real-time engine operating conditions. A control system monitors engine power setting and automatically switches tap sources to optimize efficiency: using high-pressure tap when available, transitioning to low-pressure tap during high-power operations, and mixing both sources as needed.
Solution Approach 2:
The system changes the pressure parameter of the tapped air by selecting different compressor stages. The low-pressure tap provides air at lower pressure directly suitable for aircraft systems, eliminating the need for pressure reduction and associated energy losses, while the high-pressure tap provides air when higher pressure is available and efficient.
2Temperature
If high-pressure compressor air is cooled using fan air in the bypass duct, then the tapped air is conditioned for use, but the fan air used for propulsion is undesirably heated
Solution Approach 1:
The air cooling function is segmented into separate locations: high-pressure tap air is cooled in dedicated heat exchangers positioned in the core flow path, while low-pressure tap air is cooled in separate heat exchangers. This segmentation prevents mixing of cooling air with the bypass fan air stream, preserving propulsion efficiency while achieving the required temperature reduction for air supply systems.
Solution Approach 2:
Dedicated heat exchanger components act as intermediaries between the tapped air streams and the cooling air sources. These heat exchangers enable thermal energy transfer from the tapped air to appropriate cooling air streams without direct mixing, allowing efficient cooling of both high-pressure and low-pressure tap air while preserving the integrity and efficiency of the bypass fan air stream for propulsion.
3Quantity of substance
If high-pressure and high-temperature air is tapped from the high-pressure compressor, then air supply is available, but the mid-turbine duct requires highly engineered expensive materials to handle the thermal load
Solution Approach 1:
The system performs preliminary cooling of the tapped air in heat exchangers positioned upstream, before the air reaches the mid-turbine duct region. By pre-cooling the high-pressure and low-pressure tap air streams separately, the thermal load on the mid-turbine duct is significantly reduced, allowing the use of simpler, less expensive materials while maintaining air supply availability.
4Stress or pressure
If air is compressed and then its pressure is lowered for aircraft functions, then air is supplied at required pressure, but efficiency is lost
Solution Approach 1:
The system changes the pressure parameter by tapping air at two different compressor stages: the high-pressure tap provides air at high pressure for applications requiring it, while the low-pressure tap provides air at lower pressure directly suitable for most aircraft systems. This eliminates the energy-wasting cycle of compressing air and then reducing its pressure, as air is tapped at the appropriate pressure level for its intended use.
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 approach enhances engine efficiency, reduces fuel consumption, and lowers the cooling load on the mid-turbine duct, thereby simplifying its engineering and reducing material costs.
Implementation Method 1
it is known to pass the air from the high pressure compressor tap through a heat exchanger
Implementation Method 2
The air in the bypass duct is utilized to cool the tapped air
Implementation Method 3
The air in the bypass duct is utilized to cool the tapped air
Data Source
AI summary
A gas turbine engine comprises at least two compressor rotors, including a first lower pressure compressor rotor and a second higher pressure compressor rotor. At least two corresponding air taps include a low tap for tapping low pressure compressor air from a location downstream of a first stage of the lower pressure compressor rotor, and upstream of a first stage of the higher pressure compressor rotor, and a high tap to tap air downstream of the first stage of the higher pressure compressor rotor. an air handling system selectively communicates both the low tap and the high tap to an air use destination. Air is selectively supplied from the low tap to the air handling system at a high power operation and from the high tap to the air handling system at a low power operation.