Squeeze Film Damper Drain Layout for Smaller Oil Sumps

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Solution Overview

Problem

In rotating machines, the existing oil scavenge systems require large sumps to manage the volume of oil from both bearings and squeeze film dampers, leading to space inefficiencies, particularly in applications like gas turbine engines where space is limited, and there is a need to minimize sump volume without flooding components.

Innovation Solution

The oil scavenge system reduces the volume of oil collected in the sump by directly discharging pressurized oil from the squeeze film damper into a scavenge conduit, bypassing the sump, thereby reducing the scavenge requirements and improving oil management within the sump.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oil from both bearings and squeeze film dampers is discharged into the sump, then complete oil collection is achieved, but sump volume increases

Engineering Contradiction:
Improveoil collection completenessVSAvoidsump volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The oil collection system is segmented into two separate paths: one for bearing oil discharge to the sump, and another for squeeze film damper oil discharge directly to the scavenge line, bypassing the sump. This segmentation allows the sump to handle only bearing oil, reducing its required volume while ensuring complete oil collection from both sources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The squeeze film damper oil discharge path is extracted from the sump system and connected directly to the scavenge line. This extraction removes the squeeze film damper oil volume from the sump's collection burden, enabling a smaller sump design while maintaining complete oil management.

Inventive Principle:
Principle #2Taking out (Extraction)

2Volume of stationary object

If sump volume is reduced for space efficiency, then space utilization improves, but oil scavenge capability may be compromised

Engineering Contradiction:
Improvesump volumeVSAvoidoil scavenge capability
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The oil management system is divided into two independent collection paths: bearing oil collects in the sump while squeeze film damper oil discharges directly to the scavenge line. This segmentation allows the sump to be smaller while the scavenge system maintains full capability by receiving oil from both sources through separate pathways.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The scavenge line acts as an intermediary, receiving oil directly from the squeeze film damper discharge, bypassing the sump. This intermediary connection ensures that oil scavenge capability is maintained without requiring the sump to handle all oil volumes, enabling space-efficient design.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If discharge line is positioned to direct oil into the sump, then complete oil collection is ensured, but sump volume and complexity increase

Engineering Contradiction:
Improveoil collection completenessVSAvoidsump system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The squeeze film damper discharge line is extracted from the sump system and connected directly to the scavenge line. This extraction simplifies the sump system by removing the need to handle squeeze film damper oil, reducing both volume and complexity while maintaining complete oil collection through the dual-path approach.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of directing all oil into the sump and then scavenging, the system inverts the approach by having the squeeze film damper discharge directly to the scavenge line, bypassing the sump entirely. This inversion simplifies the sump's function and reduces its required size while maintaining complete oil management.

Inventive Principle:
Principle #13The other way round (Inversion)

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 approach allows for a smaller sump design while maintaining effective oil scavenging capabilities, as the sump only needs to collect and drain oil from the bearing, reducing the overall volume of oil to be managed and enhancing space efficiency in compact applications.

Implementation Method 1

The annular channel 12 filled with pressurized oil serves to dampen motion of the bearing 14

Methodology Applied
Scientific EffectHydrodynamic pressure: Pressure Increase

Implementation Method 2

squeeze film dampers comprise a thin film of oil, which may be sealed between a pair of annular members, such that movement of an associated bearing is dampened

Methodology Applied
Scientific EffectSqueeze film damping: Damping

Implementation Method 3

The discharge line 16 may discharge oil at a bottom dead center position. The discharged oil is collected in the sump 18 via a collection orifice 20 and recirculated to a lubrication and scavenge system via a scavenge conduit 30

Methodology Applied
Scientific EffectWindage: Drag

Data Source

PatentEP3628879B1Drain arrangement for a squeeze film damper
Publication Date: 2022.10.19 ROLLS ROYCE CORP
  • EP3628879B1 patent drawingFigure 1
  • EP3628879B1 patent drawingFigure 2
  • EP3628879B1 patent drawingFigure 3

AI summary

An oil scavenge system of a rotatable machine having an axis of rotation (240) is disclosed. The oil scavenge system comprises a sump housing (232), a scavenge conduit (230), a bearing (214), and a squeeze film damper (210). The sump housing (232) is arranged about the axis (240) and at least partly defining a sump (218). The sump housing (232) has a radially inner surface (234) for directing the flow of oil and defining a collection orifice (220). The scavenge conduit (230) is in fluid communication with the collection orifice (220) and a downstream location remote from the sump (218). The bearing (214) is disposed within the sump (218). The squeeze film damper (210) is positioned proximate the bearing (214). The squeeze film damper (210) comprises an annular channel (212) and a supply line. The supply line supplies oil to the annular channel (212). The squeeze film damper (210) further comprises a discharge line (216). The discharge line (216) is axially aligned with and discharges toward an inner wall (254) of the scavenge conduit (230).