Journal Bearing Feed Slots for Rotor Lubrication and Cavitation Control

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Solution Overview

Problem

Current journal bearing configurations in rotational equipment, such as gas turbine engines, face challenges in effectively lubricating the interface between the rotor and the journal bearing, leading to issues like lubricant cavitation and potential damage to the rotor surfaces.

Innovation Solution

The proposed solution involves a lubrication system with a journal bearing that includes a lubricant circuit with grooves and slots, providing a controlled distribution of lubricant to the interface between the rotor and the journal bearing, which helps in forming a thin lubricant film and mitigating cavitation by directing lubricant to regions prone to damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional journal bearing configurations are used, then the structure is simple, but lubrication effectiveness at the rotor-bearing interface is insufficient leading to cavitation and potential rotor surface damage

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidbearing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The journal bearing is segmented with multiple lubricant feed circuits, grooves, and slots distributed around its circumference. These segmented features divide the lubrication function into multiple zones, allowing targeted lubricant delivery to specific high-risk areas at the rotor-bearing interface, thereby improving overall lubrication effectiveness without requiring a complete redesign of the bearing structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bearing incorporates localized grooves and slots at specific positions where lubrication is most critical. The lubricant feed circuits are strategically positioned to deliver lubricant precisely to regions prone to cavitation and rotor surface damage. This localized approach concentrates lubrication resources where needed most, improving reliability without uniformly increasing complexity across the entire bearing

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If lubricant is distributed to prevent cavitation, then rotor surface protection is improved, but lubricant consumption increases

Engineering Contradiction:
Improvecavitation damageVSAvoidlubricant consumption
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The lubricant feed circuits deliver lubricant to the rotor-bearing interface in advance, before cavitation can occur. The grooves and slots are positioned to provide preliminary lubrication protection at critical zones where cavitation is most likely to develop during rotor operation, preventing damage before it happens rather than reacting to it afterward

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Rather than applying lubricant uniformly across the entire bearing surface, the system uses localized grooves and slots to deliver lubricant only to specific regions where cavitation risk exists. This targeted approach protects the rotor surface from cavitation damage while minimizing unnecessary lubricant consumption in areas where protection is not needed

Inventive Principle:
Principle #3Local quality

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 configuration enhances the lubrication efficiency, reduces the risk of cavitation, and provides consistent lubrication to the sliding contact surfaces, thereby improving the operational reliability and longevity of the rotational equipment.

Implementation Method 1

a lubrication system with a journal bearing that includes a lubricant circuit with grooves and slots, providing a controlled distribution of lubricant to the interface between the rotor and the journal bearing, which helps in forming a thin lubricant film

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

providing a controlled distribution of lubricant to the interface between the rotor and the journal bearing, which helps in forming a thin lubricant film and mitigating cavitation by directing lubricant to regions prone to damage

Methodology Applied
Scientific EffectCavitation: Cavitation

Data Source

PatentEP4137675B1Feed circuit with slot(s) at interface between journal bearing and rotor
Publication Date: 2024.05.01 PRATT & WHITNEY CANADA CORP
  • EP4137675B1 patent drawingFigure 1
  • EP4137675B1 patent drawingFigure 2~3
  • EP4137675B1 patent drawingFigure 4~5

AI summary

An apparatus is provided for a turbine engine. This turbine engine apparatus includes a journal bearing extending axially along and circumferentially about an axis. The journal bearing extends radially between a bearing inner side and a bearing outer side. The journal bearing includes a bore, a passage, a groove and a slot. The bore extends axially within the journal bearing and along the bearing inner side. The passage extends radially within the journal bearing and is fluidly coupled with the bore and the groove. The groove extends longitudinally within the journal bearing at the bearing outer side between a groove first end and a groove second end. At least a portion of the slot extends circumferentially about the axis within the journal bearing at the bearing outer side from the groove first end to the groove second end.