Aircraft Engine De-Aerator Rotor to Cut Oil Trapping
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Solution Overview
Problem
Aircraft engine lubrication systems face challenges in effectively separating air from oil due to the mixing of compressed air with lubricating oil, leading to increased air content in the oil, which existing de-aerators may not adequately address.
Innovation Solution
A de-aerator design for aircraft engines featuring a rotor with specific flow passages and annular flanges that redirect and separate air-oil mixtures through centrifugation, with features like fore and aft annular shoulders and conduits to limit oil trapping and enhance air extraction, including a blow conduit for compressed air injection and drain conduits to manage oil flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If compressed air is used to pressurize the bearing cavity, then the bearing cavity is effectively pressurized, but air becomes mixed with the lubricating oil increasing air content
Solution Approach 1:
The de-aerator extracts air from the air-oil mixture using centrifugal force generated by the rotating rotor. The flow passages and annular flanges separate the air-oil mixture, with air being removed through the air outlet while oil exits through the oil outlet, thus taking out the harmful air component from the lubricating oil
Solution Approach 2:
The de-aerator utilizes the pneumatic properties of the air-oil mixture by employing centrifugal separation. The rotating rotor creates centrifugal forces that exploit the density difference between air and oil, with air being lighter and moving toward the center while oil moves outward, enabling effective separation of the two phases
2Quantity of substance
If conventional centrifugal separators are used, then air-oil separation is achieved, but oil trapping in the gap between rotor and housing occurs
Solution Approach 1:
The rotor is segmented with multiple flow passages and annular flanges that divide the air-oil mixture into separate flow paths. This segmentation prevents oil from becoming trapped in the gap by creating defined flow channels that guide oil away from the rotor-housing interface while maintaining effective air separation
Solution Approach 2:
The de-aerator introduces axial and radial dimensions to the separation process through the three-dimensional flow passages and annular flanges. Oil is directed axially through the flow passages and radially outward by centrifugal force, while air moves axially inward, creating multi-dimensional flow patterns that prevent oil trapping in the radial gap
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 de-aerator efficiently separates air from oil, reducing air content and minimizing oil trapping, thereby improving the lubrication system's performance by ensuring cleaner oil circulation and effective air expulsion.
Implementation Method 1
A de-aerator design for aircraft engines featuring a rotor with specific flow passages and annular flanges that redirect and separate air-oil mixtures through centrifugation
Data Source
Figure 1~1a
Figure 2~3
Figure 4~5
AI summary
A de-aerator (30) for a lubrication system (100), has: a housing (34) defining an air-oil inlet (30a), an oil outlet (30B), and an air outlet (30c) of the de-aerator (30); a rotor (32) received within the housing (34) and rotatable relative to the housing (34) about a central axis (A), the rotor (32) having blades (32c) distributed about the central axis (A) and extending at least partially radially relative to the central axis (A), flow passages (P) extending between the blades (32c), the rotor (32) having a hub (32b) circumferentially extending around the central axis (A) and around the blades (32c), the hub (32b) having a peripheral wall (32j2) oriented radially inwardly and defining a fore opening (32j) leading to the flow passages (P); and a gap (G) between the housing (34) and the hub (32b) of the rotor (32a), a portion of the housing (34) received within the fore opening (32j) and axially overlapping the peripheral wall (32j2) of the hub (32b), the gap (G) having a fore gap inlet (G1) between the portion of the housing (34) and the peripheral wall (32j2) of the hub (32b).