Chamber Fluid Removal Pump and Ejector System

Solution Overview

Problem

Gas turbine engine bearing chambers experience oil leakage due to pressure differential reversals, posing safety hazards and contaminating cabin air, and existing methods using compressor bleed air are inadequate, especially at low power operations or high temperature conditions.

Innovation Solution

A chamber fluid removal system utilizing a pump and ejector, where the pump generates a motive fluid from the chamber to entrain fluid using the ejector, eliminating the need for an external high-pressure source and allowing controlled pressure management within the chamber, with optional fluid bypass for additional flow capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If compressor bleed air is used to maintain positive pressure differential in bearing chambers, then oil leakage is prevented under normal conditions, but the system becomes inadequate at low power operations and high temperature conditions, and requires external high-pressure sources

Engineering Contradiction:

Improveoil leakage preventionVSAvoidperformance across varying engine conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system uses a pump to extract fluid from the bearing chamber itself and uses this extracted fluid as the motive fluid for the ejector, creating a self-sustaining system that does not require external high-pressure sources. The pump is driven by the rotation of the shaft, converting mechanical energy already present in the system into useful work for fluid removal.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically adjusts the pressure differential by using a pump whose speed can be controlled to maintain optimal conditions. The pump speed can be varied to ensure the chamber remains at lower pressure than surroundings across varying engine operating conditions, adapting to both low power and high power operations.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If compressor bleed air is used as motive fluid for ejector, then fluid removal is achieved, but the high temperature of the air poses a fire hazard

Engineering Contradiction:

Improvefluid removal capabilityVSAvoidfire hazard

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses a pump to extract fluid from the bearing chamber itself and uses this extracted fluid as the motive fluid for the ejector, creating a self-sustaining system that does not require external high-pressure sources. The pump is driven by the rotation of the shaft, converting mechanical energy already present in the system into useful work for fluid removal.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system converts the mechanical energy of the rotating shaft, which would otherwise be wasted, into useful work to drive the pump. This mechanical energy is transformed into kinetic energy of the motive fluid, which then drives the ejector to remove leaked oil, turning a potential hazard into a beneficial function.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Stress or pressure

If external high-pressure source is used to provide motive fluid, then adequate pressure is available, but the piping complexity increases and safety is reduced

Engineering Contradiction:

Improvemotive fluid pressureVSAvoidpiping requirements

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

The system uses a pump to extract fluid from the bearing chamber itself and uses this extracted fluid as the motive fluid for the ejector, creating a self-sustaining system that does not require external high-pressure sources. The pump is driven by the rotation of the shaft, converting mechanical energy already present in the system into useful work for fluid removal.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system extracts fluid from the bearing chamber and uses this extracted fluid as the motive fluid for the ejector. This eliminates the need for external high-pressure piping systems and reduces complexity by using the chamber's own contents as the driving fluid.

Inventive Principle:

Principle #2Taking out (Extraction)

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 system effectively reduces oil leakage by maintaining a lower internal pressure than the surroundings, enhancing safety and reducing piping needs, while providing consistent fluid removal without external high-pressure sources, even at varying engine conditions.

Implementation Method 1

This may be achieved using an ejector utilising compressor bled air as a motive fluid to entrain fluid from the bearing chamber

Methodology Applied

Scientific EffectEjector entrainment: Entrainment

Implementation Method 2

the pump therefore has dual functions, pumping a quantity of fluid from the chamber and providing high pressure fluid to draw further fluid from the chamber

Methodology Applied

Scientific EffectPumping: Pump

Data Source

PatentUS9567987B2Chamber fluid removal system

Publication Date: 2017.02.14 ROLLS ROYCE PLC

AI summary

A chamber fluid removal system including a pump and an ejector is disclosed. The system is arranged in use to pump fluid from a chamber using the pump and deliver it to the ejector as a motive fluid and the system being further arranged to draw fluid from the chamber or from a second chamber as an entrained fluid by entraining it using the ejector and the motive fluid.