Aircraft Engine Oil Separator Using Confuser Acceleration
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Solution Overview
Problem
Current aircraft engine oil separation devices are inefficient in separating oil from air-oil volume flows, particularly in creating larger droplets for effective separation, leading to residual oil emissions.
Innovation Solution
A device with a diffuser area upstream and a confuser area downstream, where the air-oil volume flow is introduced with oil via an outlet area, accelerating droplets to form larger droplets that deposit on the wall, combined with a cyclone for centrifugal separation, reducing oil content efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a conventional oil separator is used, then oil separation is achieved, but the separation performance is insufficient and residual oil emissions remain high
Solution Approach 1:
The conduit area is divided into distinct functional zones: a diffuser area for droplet coalescence and a confuser area for droplet acceleration and separation. This segmentation allows each zone to perform its specific function optimally, improving overall separation performance while reducing residual oil emissions.
Solution Approach 2:
The flow cross-section of the conduit area is varied along the flow direction: expanded in the diffuser area to reduce velocity and promote coalescence, then tapered in the confuser area to increase velocity and enhance separation. These parameter changes optimize the separation process and reduce harmful emissions.
2Productivity
If the flow cross-section is suddenly constricted to accelerate flow, then separation efficiency improves, but drag coefficients and pressure losses increase significantly
Solution Approach 1:
The diffuser area is positioned upstream to preliminarily prepare the flow by expanding the cross-section and reducing velocity, which promotes droplet coalescence before the confuser area accelerates the flow. This preliminary action reduces the adverse effects of sudden constriction on pressure losses.
Solution Approach 2:
The confuser area is designed with a gradual taper instead of sudden constriction, preliminarily accelerating the flow in a controlled manner. This preliminary acceleration reduces turbulence and drag coefficients while maintaining separation efficiency.
3Reliability
If small oil droplets are present in the air-oil volume flow, then oil is difficult to separate, but introducing oil to promote coalescence may increase oil loading temporarily
Solution Approach 1:
The diffuser area acts as an intermediary zone where introduced oil serves as a coalescence medium. Small oil droplets in the air-oil volume flow combine with the introduced oil in this low-velocity zone, forming larger droplets that are easier to separate in the subsequent confuser area.
Solution Approach 2:
Oil is introduced upstream in the diffuser area to perform preliminary coalescence with small droplets before the flow enters the confuser area. This preliminary action converts difficult-to-separate small droplets into easier-to-separate larger droplets, improving overall separation reliability.
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 device significantly reduces oil loading in air-oil volume flows by forming larger droplets for easier separation and using a cyclone for efficient oil removal, minimizing emissions and maintaining low pressure losses.
Implementation Method 1
a flow cross-section of an intermediate area of the closed line area, which extends at least between the outlet area of the device and the confuser area, is designed to prevent a positive acceleration of the air-oil volume flow and/or at least partially expand at least approximately like a diffuser
Implementation Method 2
an at least approximately laminar flow is formed in the intermediate area of the closed conduit area
Implementation Method 3
a flow cross-section of the conduit area downstream of the outlet area of the device tapers in a confuser area at least partially at least partially like a nozzle, the air-oil volume flow to which oil is applied via the outlet area of the device being accelerated in the confusion area
Implementation Method 4
a cyclone, in the area of which oil can be mechanically switched off from an air-oil volume flow which is to be introduced into the line area or is carried out from it
Implementation Method 5
the air, as the carrier of the oil, is set in rotation by its own flow speed and the corresponding structural design of the cyclone
Implementation Method 6
the introduction of oil into the air-oil volume flow creates oil droplets in this oil which are largely larger than oil droplets which, due to their small size, cannot be separated or can only be separated with great effort
Data Source
Figure 1a~1b
Figure 2
Figure 3~5
AI summary
A device (40) of an aircraft engine for separating oil from an air-oil flow is described, comprising a device (41) for introducing oil into the air-oil flow. An outlet region (42) of the device (41) is provided for introducing oil into a closed conduit region (43), into which the air-oil flow can be introduced via an inlet region (44). According to the invention, a flow cross-section of the conduit region (43) downstream of the outlet region (42) of the device (41) narrows, at least partially, in a nozzle-like manner within a confusing section (45).