Cabin Air Pressurisation Using Bypass Compression and Core Bleed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing air pressurisation systems for aircraft cabins using engine bleed air from turbofan engines reduce engine efficiency and increase fuel consumption, and alternative systems that use air from lower pressure sources require additional compression, which can be inefficient.
Innovation Solution
An air pressurisation system that includes a blower compressor coupled to a turbofan engine's spool, an air treatment apparatus with an air cycle line and a bypass line, and an engine core bleed line, allowing for mixing and temperature control of air flows from different sources to optimize air supply to the cabin, with a controller to switch between augmented and unaugmented modes based on demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If engine bleed air is used for cabin pressurisation, then air supply to the cabin is ensured, but engine efficiency is reduced and fuel consumption increases
Solution Approach 1:
The system divides the air supply function into two separate sources: a blower compressor for normal operation and an engine core bleed line for augmented supply. This segmentation allows the system to use the most efficient source (blower) while having a backup option (engine bleed) without constantly compromising engine efficiency.
Solution Approach 2:
The system dynamically switches between different air supply modes (unaugmented and augmented) based on operational requirements. The controller adjusts which air source is used, allowing the system to optimize for fuel efficiency during normal operation while ensuring adequate air supply when demand increases.
2Loss of energy
If air from lower pressure source is used, then engine efficiency is improved, but additional compression is required which reduces efficiency
Solution Approach 1:
The blower compressor acts as an intermediary device that takes low-pressure air from the bypass duct and compresses it to the required pressure for cabin supply. This intermediary approach allows the system to use low-pressure air sources without directly compromising engine efficiency, as the blower is a dedicated compression device optimized for this purpose.
3Quantity of substance
If engine core bleed air is used in augmented mode, then sufficient air supply is ensured, but system complexity increases
Solution Approach 1:
The air treatment apparatus is designed to handle multiple air sources universally. The same conditioning system processes air whether it comes from the blower compressor or the engine core bleed line, reducing the need for separate conditioning systems and thereby limiting the increase in overall system complexity despite the augmented supply capability.
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
Improves engine efficiency and reduces fuel consumption by utilizing air from lower pressure sources without additional compression, while ensuring sufficient air supply to the cabin, maintaining optimal temperature and pressure conditions.
Implementation Method 1
a blower compressor configured to be mechanically coupled to a spool of a turbofan engine and configured to receive a first inlet flow of air from a bypass duct of the turbofan engine
Implementation Method 2
an air cycle line configured to condition air received from the blower compressor
Implementation Method 3
the air treatment apparatus is configured to mix air from the air cycle line with air from the bypass line to control a temperature of air for discharge to an airframe system
Implementation Method 4
an engine core bleed line configured to provide a second inlet flow of air from a compressor of the turbofan engine to the air treatment apparatus in an augmented air supply mode
Data Source
Figure 1~2
Figure 3
Figure 4A
AI summary
There is provided an air pressurisation system 400 comprising: a blower compressor 420 configured to be mechanically coupled to a spool 440 of a gas turbine engine and configured to receive a first inlet flow of air from a bypass duct 22 of the gas turbine engine; an air treatment apparatus 460 comprising an air cycle line 470 configured to condition air received from the blower compressor 420, and a bypass line 480 for receiving air from the blower compressor, and configured to bypass the air cycle line 470, wherein the air treatment apparatus 460 is configured to mix air from the air cycle line 470 with air from the bypass line 480 to control a temperature of air for discharge to an airframe system 450; and a core bleed line 410 configured to provide a second inlet flow of air from a compressor 412 of the gas turbine engine to the air treatment apparatus 460 in an augmented air supply mode of the air pressurisation system 400; wherein the core bleed line 410 is configured to provide the second inlet flow of air directly to the bypass line 480 or mix the second inlet flow of air with air from the blower compressor 420 upstream of the bypass line 480.