Cabin Air Compressor Housing Cooling Design
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Solution Overview
Problem
Aircraft cabin air compressors face challenges in maintaining adequate cooling for bearings while efficiently directing compressed air flows, as existing designs often result in overheating due to inefficient airflow distribution and leakage around the compressor rotor seal.
Innovation Solution
The cabin air compressor housing features a compressor volute and journal bearing support with a specific ratio of cooling airflow hole diameters, forming a mixing chamber that combines bearing cooling flow with leaked air to create a cooling outlet flow through strategically positioned airflow holes, ensuring effective cooling and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling airflow holes are made larger to improve bearing cooling, then cooling efficiency improves, but structural integrity and compression efficiency deteriorate due to excessive leakage around the rotor seal
Solution Approach 1:
The patent applies parameter changes by optimizing the diameter ratio of cooling airflow holes to journal bearing bore within a specific range (0.22-0.27) to balance cooling efficiency and compression efficiency. This quantitative parameter optimization resolves the contradiction by finding the optimal middle ground where bearing cooling is sufficient while leakage-induced compression efficiency loss is minimized
2Productivity
If cooling airflow holes are made smaller to maintain compression efficiency, then leakage around rotor seal is reduced, but bearing cooling efficiency deteriorates
Solution Approach 1:
The patent uses parameter changes by establishing a minimum diameter ratio threshold (0.22) for cooling airflow holes to ensure adequate bearing cooling while maintaining compression efficiency. This quantitative boundary resolves the contradiction by defining the smallest acceptable hole size that still provides sufficient cooling
3Temperature
If the diameter ratio of cooling airflow holes to journal bearing bore is increased beyond the optimal range, then bearing cooling improves, but structural integrity deteriorates
Solution Approach 1:
The patent applies parameter changes by setting an upper bound (0.27) on the diameter ratio of cooling airflow holes to journal bearing bore to maintain structural integrity while providing adequate cooling. This quantitative constraint resolves the contradiction by preventing excessive hole sizes that would compromise structural strength
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 design enhances cooling efficiency by maintaining structural integrity and directing airflow effectively, preventing overheating of bearings and ensuring optimal performance of the compressor assembly.
Implementation Method 1
a bearing cooling flow is supplied to the bearings. The bearing cooling flow proceeds across the bearings to remove thermal energy from the bearings
Implementation Method 2
The mixing chamber is configured to receive a bearing cooling flow through the journal bearing bore and a portion of air flow that leaks past the compressor rotor seal
Data Source
AI summary
A cabin air compressor housing for a cabin air compressor assembly includes a compressor volute configured to direct a compressed flow to a compressor outlet. The cabin air compressor housing also includes a journal bearing support having a journal bearing bore. The cabin air compressor housing further includes an interior portion between the compressor volute and the journal bearing support. The interior portion includes a plurality of cooling airflow holes having a ratio of a diameter of the journal bearing bore to a diameter of one of the cooling airflow holes between 3.64 and 4.52.