Bearing Cooling Flow Isolation for Aircraft Cabin Air Purity
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Solution Overview
Problem
In air cycle machines, the cooling airflow for bearings can entrain smoke, odors, or other impurities, which are then discharged into the compressor flow or turbine airflow and can reach the aircraft cabin, posing an undesirable contamination risk.
Innovation Solution
The cooling airflow is maintained separate from the main airflow by directing leakage paths across seals to an ambient pressure outlet, preventing contamination of the aircraft cabin by ensuring the cooling air does not mix with the compressor or turbine airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is discharged into the compressor flow or turbine airflow to cool bearings, then the bearings are cooled effectively, but smoke, odors, or other impurities are entrained and reach the aircraft cabin
Solution Approach 1:
The patent divides the airflow system into separate segments: a first airflow path for bearing cooling that discharges to ambient pressure, and a second airflow path for cabin air supply. This segmentation prevents the mixing of potentially contaminated bearing cooling air with the clean air intended for the cabin, while still allowing effective cooling of the bearings through the dedicated first path.
2Object-affected harmful factors
If cooling airflow is separated from main airflow to prevent contamination, then air cabin purity is improved, but the complexity of the airflow system increases
Solution Approach 1:
The patent merges the bearing cooling function with the ambient pressure discharge system by utilizing the existing pressure differential. The first airflow path for bearing cooling is combined with the ambient pressure outlet that already exists in the system, eliminating the need for separate cooling mechanisms and reducing overall system complexity while maintaining air purity.
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 effectively isolates the bearing cooling airflow from the cabin air supply, preventing the introduction of smoke, odors, or impurities into the aircraft cabin, thereby ensuring a cleaner and safer air delivery system.
Implementation Method 1
Cooling airflow is supplied along the thrust bearings and radially inwardly to cool the thrust bearings and drive shaft
Implementation Method 2
A second connection is provided at ambient pressure and is separate from the first connection
Data Source
Figure 1
Figure 2
AI summary
A machine for use in an environmental control system has a turbine impeller (125). A turbine inlet (124) is connected to supply compressed air to drive the turbine impeller. There is a compressor impeller (122) and a compressor inlet (121) connected to supply air to be compressed to the compressor impeller. The compressor impeller delivers air to a compressor outlet (25). The compressor outlet is connected to the turbine inlet. A turbine outlet is connected to a first connection (131) connected to an aircraft. The turbine impeller is connected to the compressor impeller by a drive shaft (141). The drive shaft includes a radially outwardly extending thrust disk, and thrust bearings provided on each of two axial sides of the thrust disk (128). A cooling air inlet (130) is connected to pass air along the thrust bearings, then radially inwardly and then axially along the shaft. The cooling air is directed to a cooling air outlet (214). The cooling air outlet is connected to a second connection (215) maintained separate from the first connection. An environmental control system is also disclosed.