Compressor Seal Baffle Geometry for High-Speed Oil Drainage
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Solution Overview
Problem
In turbomachines, particularly turbochargers, there is a tendency for oil to form and block the drainage flow at the baffle surface, leading to oil leakage towards the compressor, which is exacerbated by high rotational velocities of the oil, reducing drainage efficiency.
Innovation Solution
A baffle element with a circumferentially-extending oil-receiving channel and an oil-deflecting surface is designed, where the channel decreases in cross-sectional area near the oil-deflecting surface, converting circumferential velocity into axial velocity to efficiently expel oil from the baffle, maintaining high rotational velocity while improving drainage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional baffle with central opening is used, then oil can be drained from the bearing housing, but oil forms a rotating body that blocks the drainage flow and causes leakage towards the compressor
Solution Approach 1:
The baffle surface is segmented into multiple radial drainage channels instead of a single central opening. This segmentation prevents the formation of a continuous rotating oil body that blocks drainage, as the oil is divided into multiple separate flow paths that can drain simultaneously without mutual interference.
Solution Approach 2:
Different regions of the baffle surface are given different functions: the central region collects oil, while radial channels provide dedicated drainage paths. The channel geometry is locally optimized with specific cross-sectional areas and orientations to maintain drainage efficiency under rotational conditions.
2Force
If the rotational velocity of oil is increased, then the outward force pushing oil away from the central opening increases, but a greater volume of oil must be accommodated in the seal cavity and drainage efficiency decreases
Solution Approach 1:
The drainage channels are oriented radially outward from the center, utilizing the radial dimension to accommodate the centrifugal force generated by high rotational velocities. This dimensional alignment allows oil to follow natural centrifugal paths, maintaining drainage efficiency even at higher rotational speeds.
Solution Approach 2:
The cross-sectional area of the drainage channels is specifically designed to increase toward the periphery, matching the increasing volume of oil that must be accommodated at higher rotational velocities. This parameter optimization ensures that drainage capacity scales with rotational speed.
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 solution effectively enhances the drainage efficiency of the seal system by redirecting oil flow, reducing oil leakage and accommodating higher rotational speeds without compromising drainage performance.
Implementation Method 1
Some rotational velocity of the body of oil is desirable, as this rotational velocity generates an outward force which pushes the body of oil away from the central opening of the baffle
Data Source
Figure 1
Figure 2~3
Figure 4a~4b
AI summary
A seal system for a bearing chamber (22) of a turbomachine includes the baffle element (70) encircling the axis (25) of the machine. The baffle element is formed with front surface including both a recess (73) which defines acircumferentially-extending oil-receiving channel (74), and an oil-deflecting surface (78) on a gutter (77). The channel decreases in cross-sectional area close to the oil-deflecting surface, and a circular line which is within the channel distant from the gutter, intersects with the oil-deflection surface. This forces the oil to change direction at the gutter, and urges the oil radially outward. Thus, a high rotational velocity of the body of oil may be maintained, whilst improving the drainage efficiency of the seal systemat the gutter.